Volume 4, Supplement 1

Transcription

G
LOBAL
GAJ ANTIVIRAL
JOURNAL
™
2008
HIV
December 9-12, 2008
Wyndham Grand Rio Mar Hotel
Puerto Rico
Final Program and Abstract Book
This program is sponsored by Emory University School of Medicine
GAJ
Volume 4, Supplement 1
GAJ
GLOBAL
ANTIVIRAL
JOURNAL
Aims and Scope
Global Antiviral Journal publishes peer-reviewed original works related to international efforts to advance antiviral
discovery and development, including full-length articles and short papers, as well as solicited review articles, conference
reports, letters and book reviews. Occasional supplements contain conference abstracts, presentations and/or posters
from international meetings in the fields of virology and antiviral research. The scope of the journal encompasses
chemistry and biological advances in the fundamental and clinical study of antiviral diseases and their treatment. Areas
covered include HIV, hepatitis B, hepatitis C and emerging viruses, co-infections, vaccines, animal models, pharmacology,
microbicides, alternative therapies, viral dynamics and resistance issues.
The journal is published online by IHL Press at www.ihlpress.com/gaj.html.
All printed supplements are also made available online.
Publication Policy
Global Antiviral Journal publishes only original, documented research of high scientific quality, following accepted ethical
standards of research. Submission of a manuscript signifies that it has been neither copyrighted, published, nor submitted
or accepted for publication elsewhere.
Editor-in-Chief
Raymond F. Schinazi, Emory University School of Medicine and Veterans Affairs Medical Center, Department of Pediatrics,
Medical Research 151H, 1670 Clairmont Road, Decatur, Georgia, 30033, USA
Editorial Office
IHL Press, 26 Bailey Road, Arlington, MA, 02476, USA
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Copyright
© 2008 IHL Press. All rights reserved.
No part of this work may be reproduced, stored in a retrieval system or transmitted in any form or by any means,
electronic, mechanical, photocopying, recording or otherwise, without prior written permission of the Publisher.
Notice
No responsibility is assumed by the Publisher for any injury and/or damage to persons or property as a matter of products
liability, negligence or otherwise, or from any use or operation of any methods, products, diagnoses, drug dosages,
instructions or ideas contained in the material herein.
ISSN (print): 1556-9047
ISSN (online): 1556-9055
™
HIV
2008
December 9-12, 2008 • Wyndham Grand Rio Mar Hotel • Puerto Rico
Final Program
and Abstract Book
HIV DART 2008 - Frontiers in Drug Development for Antiretroviral Therapies
i
Table of Contents Page
Corporate Supporters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Continuing Medical Education. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Scholarships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Conference Committees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Social Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Scientific Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Abstracts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
Pathogenesis and Targeted Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Toward HIV Eradication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Prevention and Drug Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
HIV Therapy in Developing Countries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
HIV/Hepatitis and Other Co-infections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Novel Therapeutic Approaches: Antiviral Mechanism and Predictive Toxicology. . . . . . . . . . 47
Pharmacology and Drug Metabolism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Author Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Appendix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Late Breaker Abtracts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
CME Program Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
iii
HIV DART 2008 is supported by independent educational grants from the following:
Gold Support
Silver Support
Bronze Support
RFS Pharma, LLC • Samchully Pharm. Co., Ltd
Additional Support
ACLIRES International Ltd. • American Academy of HIV Medicine
Department of Veterans Affairs • Presidio Pharmaceuticals, Inc.
HIV DART 2008 is also supported in part by Grant Number 5R13AI065203 from the National Institute of
Allergy and Infectious Diseases. The views expressed in written conference materials or publications and by
speakers and moderators do not necessarily reflect the official policies of the Department of Health and Human
Services; nor does mention of trade names, commercial practices, or organizations imply endorsement by the
U.S. Government.
The Organizers would like to thank The NAMES Project Foundation for partnering with HIV DART 2008
to display sections of the AIDS Quilt memorializing Puerto Ricans who lost their lives to AIDS.
“A memorial, a tool for education and a work of art, the Quilt is a unique creation, an uncommon and
uplifting response to the tragic loss of human life.” –The NAMES Project, www.aidsquilt.org
iv
Global Antiviral Journal Volume 4, Supplement 1
Continuing Medical Education
HIV DART 2008 is sponsored by Emory University School of Medicine.
Conference Objectives
HIV DART was designed to interest physicians, clinicians, scientists and clinical researchers in the
HIV/co-infection arena. The educational objectives of this program are as follows:
• Understand the role of viral targets in the drug discovery and development process
• Identify novel therapeutic agents and viral targets
• Develop improved strategies to reduce or eliminate drug-resistance and toxicity
• Provide insights on novel immunological approaches compatible with clinical drug development
• Develop approaches to eliminate or eradicate HIV from viral reservoirs
• Understand the consequences of co-infection with hepatitis B & C on the management of subjects
with HIV infection
Continuing Medical Education
Accreditation Statement: Emory University School of Medicine is accredited by the Accreditation
Council for Continuing Medical Education to provide continuing medical education for physicians.
Credit Designation Statement: Emory University School of Medicine designates this educational
activity for a maximum of 17 AMA PRA Category 1 Credit(s)TM. Physicians should only claim credit
commensurate with the extent of their participation in the activity.
Scholarships
Conference scholarships were provided for post-doctoral fellows, nurses, assistant professors,
underrepresented minorities, and residents of developing countries.
2008 Scholarship Recipients
Jules Levin, NATAP, USA
Terence McPhaul, National AIDS Education & Services for Minorities, USA
Andy Mtambo, BC Centre for Excellence in AIDS/HIV, Canada
Mrunalee Patil, Emory University School of Medicine, USA
Maria Sandu, Clinical Hospital for Infectious Diseases, Romania
Tracy Swan, Treatment Action Group, USA
v
Organizing Committee
David Cooper, Co-chair
José Rodriguez-Orengo, Local Chair
Joep Lange, Co-chair
Raymond F. Schinazi, Chair
Robert Murphy, Chair
Jean-Pierre Sommadossi, Emeritus Chair
University of New South Wales, Australia
University of Amsterdam, the Netherlands
Northwestern University, USA
Instituto de Ciencias Forenses, Puerto Rico, USA
Emory University/VA Medical Center, USA
Idenix Pharmaceuticals, USA
Scientific Committee
Françoise Brun-Vézinet
Alain Lafeuillade
Sal Butera
Hiroaki Mitsuya
Pedro Cahn
Julio Montaner
Bonaventura Clotet
Alan Perelson
Steven Deeks
Praphan Phanuphak
Courtney Fletcher
Richard Pollard
Joel Gallant
Bruce Polsky
José Gatell
François Raffi
Brian Gazzard
Douglas Richman
Matthias Götte
Ian Sanne
Eric Hunter
Charles van der Horst
John Idoko
Stefano Vella
Christine Katlama
Mark Wainberg
Hôpital Bichat Claude Bernard, France
Centers for Disease Control and Prevention, USA
Fundación Huesped, Argentina
Fundacio IRSI Caixa, Spain
University of California, San Francisco, USA
University of Nebraska Medical Center, USA
Johns Hopkins University School of Medicine, USA
Hospital Clinic, Spain
Chelsea & Westminster Hospital, UK
McGill University, Canada
Emory Vaccine Center, USA
Jos University Teaching Hospital, Nigeria
Groupe Hospitalier Pitié-Salpêtrière, France
Chalucet Hospital, France
Kumamoto University School of Medicine, Japan
BC Centre for Excellence in HIV/AIDS, Canada
Los Alamos National Laboratory, USA
Thai Red Cross AIDS Research Centre, Thailand
University of California, Davis Medical Center, USA
St. Luke’s-Roosevelt Hospital Center, USA
Centre Hospitalier Universitaire de Nantes, France
University of California, San Diego/VA Medical Center, USA
Wits Health Consortium, South Africa
University of North Carolina at Chapel Hill, USA
Istituto Superiore di Sanità, Italy
McGill AIDS Centre, Canada
Paolo La Colla
Università degli Studi di Cagliari, Italy
vi
Social Functions
Welcome Reception
Tuesday, December 9, 2008
18:00
Pool Patio East, Wyndham Grand Rio Mar
Poster Session Reception
Wednesday, December 10, 2008
16:00 - 18:30
Caribbean Ballroom
Gala Party
Thursday, December 11, 2008
20:00
Vista Verde Garden, Wyndham Grand Rio Mar
Conference Secretariat
1631 Phoenix Boulevard, Suite 4
College Park, Georgia 30349 USA
Telephone: +1 770 997 2484
Facsimile: +1 770 997 2488
E-mail: info@informedhorizons.com
Website: www.informedhorizons.com
vii
HIV DART 2008
Frontiers in Drug Development for Antiretroviral Therapies
Scientific Program
Tuesday, December 9, 2008
Abstract
18:00 Welcome Reception
Wednesday, December 10, 2008
8:00
Opening Remarks and Presentation of the Gertrude Elion Distinguished Lecturer Award
Raymond F. Schinazi
Emory University/Veterans Affairs Medical Center, USA
Robert Murphy
8:15
Gertrude Elion Distinguished Lecturer Award
Approaches towards HIV-1 Eradication: Harnessing Cellular Restrictions Mario Stevenson
University of Massachusetts Medical School, USA
Pathogenesis and Targeted Design
Chairs: Daria Hazuda Leonid Margolis
01
Merck Research Labs, USA
National Institute of Child Health and Human Development, USA
8:55 Understanding HIV Maturation using Electron Cryotomography Elizabeth Wright
California Institute of Technology, USA
02
9:15
Vpu and its Cellular Targets Paul Spearman
Emory University School of Medicine, USA
03
9:35
Cell Penetrating Peptides: From Molecular Mechanisms to Therapeutics Gilles Divita CNRS, France
04
9:55
Panel Discussion
10:15 Break
Toward HIV Eradication I
Chairs: Bruce Polsky
Matthias Götte
St. Luke's Roosevelt Hospital Center, USA
10:35 Complementary Mechanisms of Nucleoside Analog Resistance from Structural Studies of HIV-1 Reverse Transcriptase
Eddy Arnold Rutgers University, USA
06
10:55 Dose Response Curve Slope Sets Class Specific Limits on Inhibitory Potential of Anti-HIV Drugs
Robert Siliciano Johns Hopkins University School of Medicine and
Howard Hughes Medical Institute, USA
07
11:15 Pharmacology, Metabolism and Transport of HIV Drugs into Viral Reservoirs
Saye Khoo University of Liverpool, UK
08
11:35 Panel Discussion
ix
Abstract
Oral Abstract Session I
Chairs: Charles Boucher Adrian Ray Erasmus Medical Center Rotterdam and
University Medical Centre Utrecht, the Netherlands
Gilead Sciences, Inc., USA
11:55 Immunotoxins to Selectively Deplete Reservoirs of HIV-infected Cells that Persist in the
Face of Highly Suppressive Antiretroviral Therapy
Edward Berger National Institutes of Health, USA
09
12:05 Development of Pyrimidinedione NNRTIs with a High Genetic Barrier to Resistance
Robert Buckheit ImQuest BioSciences, USA
10
12:15 Development of VS411, a Virostatic Drug Fixed Dose Combination (FDC) Designed to Inhibit both HIV and Immune Hyperactivation
Franco Lori ViroStatics Srl, Italy
11
12:25 Inhibiting Vpu Function with the Novel Compound BIT225, Results in Inhibition of HIV-1 Release from Human Macrophage Reservoirs
John Wilkinson Biotron Limited, Australia
12
12:35 Lunch
14:00 – 16:00
Free Afternoon
16:00 – 18:30
Poster Session
Toward HIV Eradication II
Chairs: Raymond F. Schinazi
Emory University/Veterans Affairs Medical Center, USA
Ian Sanne
18:30
State of the Art Lecture
Integrase Inhibitors: New Insights into Mechanism of Action and Pharmacology with
Implications for Treatment and Prevention Strategies
Daria Hazuda Merck Research Labs, USA
13
19:00 A Non-human Primate Model for Development of AIDS Eradication Strategies
Thomas North University of California, Davis, USA
14
19:20 Diminution of HIV Latency through Blockage of Arginine Methylation of Viral Proteins
Mark Wainberg McGill University AIDS Centre, Canada
15
x
THURSDAY, DECEMBER 11, 2008
Prevention and Drug Resistance
Chairs: Mark Wainberg
Douglas Mayers
Abstract
McGill University AIDS Centre, Canada
Idenix Pharmaceuticals, Inc., USA
8:00
Presentation of David Barry DART Achievement Award
Robert Murphy Northwestern University, USA
The Award will be given to Dr. Larder by Mrs. Gracia Barry
8:10
David Barry DART Achievement Award
Milestones in HIV Drug Resistance: From in Vitro to in Silico
19
Brendan Larder
HIV Resistance Response Database Initiative (RDI), UK
8:50
STOP HIV/AIDS: Seek and Treat for Optimal Prevention of HIV/AIDS
Julio Montaner British Columbia Centre for Excellence in HIV/AIDS, Canada
9:10 Transmission of Drug Resistant HIV: Patterns of Resistance to New Antiretroviral Agents and their Clinical Relevance
Charles Boucher Erasmus Medical Center Rotterdam and University Medical
Centre Utrecht, the Netherlands
9:30 Panel Discussion 9:50
Break
HIV Therapy in Developing Countries
Chairs: Christine Katlama José Gatell
20
21
Hôpital Pitié-Salpêtrière, France
University of Barcelona, Spain
10:10 Experiences in HIV Treatment in Developing Countries
Ian Sanne
10:30 To Wean or not to Wean: Prevention of Mother-to-child Transmission through Breast Milk
Charles van der Horst
30
10:50 Topical Microbicides: Moving towards Topical Pre-exposure Prophylaxis (PrEP)
Sharon Hillier
University of Pittsburgh School of Medicine, USA
31
Oral Abstract Session II
Chairs: Charles van der Horst
Paul Spearman 11:30
Emory University, USA
Glycan Deletions in the HIV-1 gp120 V1/V2 Domain Compromise Viral Infectivity, Sensitize the Mutant Virus Strains to Carbohydrate Binding Agents and Represent a Specific Target
for Therapeutic Intervention
Joeri Auwerx K.U. Leuven, Rega Institute for Medical Research, Belgium
11:40 Gag NC/p1 Protease Resistance Mutations can cause Selection of Additional NC/p1 Changes to Optimize Cleavage Efficiency and Replicative Capacity
Monique Nijhuis University Medical Centre Utrecht, the Netherlands
32
33
xi
Abstract
11:50 Safety, Tolerability and Efficacy of Darunavir/ritonavir in Treatment-experienced Women with HIV Infection: Interim Analysis of GRACE (Gender, Race, And Clinical Experience)
Carmen Zorrilla University of Puerto Rico School of Medicine, USA
34
12:00 96-Week (wk) Efficacy and Safety of Raltegravir (RAL) in Treatment-experienced Patients José Gatell
University of Barcelona, Spain
35
12:10 Lunch on your own
13:30 – 17:00
Free Afternoon
HIV/Hepatitis and Other Co-infections
Chairs: Tracy Swan
Treatment Action Group, USA
Joep Lange
17:00 State of the Art Lecture
The Aging Liver in the HIV Population Douglas Dieterich Mount Sinai School of Medicine, USA
17:30 Co-infection with HCV and HBV: When and How to Treat? Bruce Polsky St. Luke's Roosevelt Hospital Center, USA
Poster Discussion
17:50 Poster Review, Part I
Joep Lange
18:20 Poster Review, Part II
Adrian Ray
37
38
20:00 Gala Party
FRIDAY, DECEMBER 12, 2008
Novel Therapeutic Approaches: Antiviral Mechanism and Predictive Toxicology
Chairs: Carmen Zorrilla
University of Puerto Rico School of Medicine, USA
Richard Pollard
University of California, Davis Medical Center, USA
8:00
State of the Art Lecture
Optimizing HAART Therapy in the Era of Integrase and Entry Inhibitors Christine Katlama Hôpital Pitié-Salpêtrière, France
8:30
IDX-899 -- A Novel Once-a-day Second Generation NNRTI for the Treatment of HIV/AIDS Douglas Mayers
Idenix Pharmaceuticals, Inc., USA
43
8:50
Vicriviroc: A Next Generation CCR5 Antagonist for Treatment of HIV Lisa Dunkle Schering-Plough Research Institute, USA
44
9:10
Amdoxovir Combined with Low Dose AZT for HIV-1 Therapy Robert Murphy
45
9:30
Break
9:50
A New Era in HIV-antiretroviral Therapy: Darunavir, Etravirine and TMC278 Eric Lefebvre
Tibotec, the Netherlands
xii
42
46
Abstract
10:10 Low Potential for Class Related Toxicity of Next Generation Nucleotide Analog GS-9148 Adrian Ray
47
10:30 Mechanisms Associated with Delayed HIV RT Chain-termination Matthias Götte
48
11:10 Break
11:30 Special Lecture
Acyclovir as an HIV-1 RT Inhibitor in Herpesvirus-infected Human Tissues Leonid Margolis
National Institute of Child Health and
Human Development, USA
Oral Abstract Session III
Chairs: Lisa Dunkle
José Rodriguez-Orengo
49
Schering-Plough Research Institute, USA
Instituto de Ciencias Forenses, Puerto Rico, USA
11:50 Comparison of Two Human Pancreatic Cell Lines for Predicting Mitochondrial Toxicity by Nucleoside Analogs
Leda Bassit Emory University School of Medicine and
VA Medical Center, USA
50
12:00 ARTEMIS: Efficacy and Safety of Darunavir/ritonavir (DRV/r) 800/100 mg Once-daily vs. Lopinavir/ritonavir (LPV/r) in Treatment-naïve, HIV-1-infected Patients at 96 Weeks
Dushyantha Jayaweera University of Miami, USA
51
12:10 Etravirine (ETR; TMC125) Demonstrates Favorable Efficacy and Safety in the Phase III DUET Trials Regardless of Geographic Location
Christine Katlama
Hôpital Pitié-Salpêtrière, France
52
12:20 Pharmacokinetics and Short-term Safety and Efficacy of Once-daily Etravirine Without and With Once-daily Darunavir/ritonavir in Antiretroviral-naïve HIV-1 Infected Adults
James Witek
Tibotec Therapeutics, USA
53
12:30 Late Breaker Presentations
12:50 Closing Remarks
Raymond F. Schinazi Emory University/Veterans Affairs Medical Center, USA
13:10 Lunch
xiii
Abstracts
page
session
title and author
abstract
1
Pathogenesis and Targeted Design
3
Approaches towards HIV-1 Eradication: Harnessing Cellular Restrictions
01
M Stevenson
3
Understanding HIV Maturation using Electron Cryotomography
02
ER Wright
4
Vpu and Its Cellular Targets
P Spearman
03
5
Cell Penetrating Peptides: From Molecular Mechanisms to Therapeutics
G Divita
04
6
Foot Fractures in HIV-infected Patients Previously Treated with Tenofovir (TDF)- versus Non-TDF-containing Highly Active Antiretroviral
Therapy (HAART)
G Pakes
05
9
Toward HIV Eradication
11
Complementary Mechanisms of Nucleoside Analog Resistance from 06
Structural Studies of HIV-1 Reverse Transcriptase
E Arnold
11
Dose Response Curve Slope Sets Class Specific Limits on Inhibitory Potential of Anti-HIV Drugs
RF Siliciano
07
12
Pharmacology, Metabolism and Transport of HIV Drugs into Viral Reservoirs
S Khoo
08
13
Immunotoxins to Selectively Deplete Reservoirs of HIV-infected Cells that Persist in the Face of Highly Suppressive Antiretroviral Therapy
EA Berger
09
14
Development of Pyrimidinedione NNRTIs with a High Genetic Barrier to Resistance
RW Buckheit Jr.
10
14
Development of VS411, a Virostatic Drug Fixed Dose Combination (FDC) Designed to Inhibit both HIV and Immune Hyperactivation
F Lori
11
15
Inhibiting Vpu Function with the Novel Compound BIT225, Results in Inhibition of HIV-1 Release from Human Macrophage Reservoirs
J Wilkinson
12
xv
page
session
title and author
abstract
16
Integrase Inhibitors: New Insights into Mechanism of Action and Pharmacology with Implications for Treatment and Prevention Strategies
D Hazuda
13
17
A Non-human Primate Model for Development of AIDS Eradication Strategies
TW North
14
17
Diminution of HIV Latency through Blockage of Arginine Methylation of Viral Proteins
MA Wainberg
15
18
Combination Therapy for Treating HIV Latency
TP Castor
16
19
Inhibition of Late Stage Events in HIV-1 Replication: Discovery and Development of Therapeutic Compounds with Effects on Viral RNA Synthesis
Which Potentially Target Rev Function
TL Hartman
17
20
HIV Infected Refugees: ART Therapy and Its Affect on CD4 Counts at 3 and 6 Months
M Patil
18
21
Prevention and Drug Resistance
23
Milestones in HIV Drug Resistance: From In Vitro to In Silico
B Larder
19
23
STOP HIV/AIDS: Seek and Treat for Optimal Prevention of HIV/AIDS
J Montaner
20
24
Transmission of Drug Resistant HIV: Patterns of Resistance to New Antiretroviral Agents and their Clinical Relevance
CAB Boucher
21
25
Ninety-nine Is Not Enough: Kinetic, Structural and Thermodynamic Characterization of HIV Protease with Insertion in the Flap Region Isolated
from an HIV-positive Patient
M Kožíšek
22
25
TOPO Cloning and Pyrosequencing Revealed a Novel S68 Deletion in HIV-1 Reverse Transcriptase Selected by Dexelvucitabine in Human Lymphocytes
I Massud
23
26
Operation Sweet Tooth: Effective Use of Social Marketing Campaigns in Non-Traditional Social Settings
T McPhaul
24
xvi
page
session
title and author
abstract
27
Utilizing Mental Health Counseling in African American Men who have Sex with Men Minority Populations as a Primary and Secondary HIV
Prevention Tool
T McPhaul
25
28
Sex is Good: An Investigation into the Quality of Life and Sexual Practices Among Individuals on HAART in British Columbia
A Mtambo
26
29
Vertical Transmission of HIV Infection in Western Romania
M Sandu
27
29
Development of the Dual Acting Pyrimidinedione IQP-0528 as a Vaginal Topical Anti-HIV Microbicide
KM Watson
28
30
Development of Resistance to Enfuvirtide in Cerebrospinal Fluid in a Patient with Suppressed Plasma HIV-1 RNA
AMJ Wensing
29
33
HIV Therapy in Developing Countries
35
To Wean or Not to Wean: Prevention of Mother-to-child Transmission through Breast Milk
C van der Horst
30
36
Topical Microbicides: Moving Towards Topical Pre-exposure Prophylaxis (PrEP)
S Hillier
31
36
37
Glycan Deletions in the HIV-1 gp120 V1/V2 Domain Compromise Viral Infectivity, Sensitize the Mutant Virus Strains to Carbohydrate Binding
Agents and Represent a Specific Target for Therapeutic Intervention
J Auwerx
32
Gag NC/p1 Protease Resistance Mutations can cause Selection of Additional NC/p1 Changes to Optimize Cleavage Efficiency and Replicative Capacity
M Nijhuis
33
38
Safety, Tolerability and Efficacy of Darunavir/ritonavir in Treatment-
experienced Women with HIV Infection: Interim Analysis of GRACE
(Gender, Race, And Clinical Experience)
C Zorrilla
34
39
96-Week (wk) Efficacy and Safety of Raltegravir (RAL) in Treatment-
experienced Patients
J Gatell
35
40
Valacyclovir as Antiretroviral Therapy
M Pop
36
xvii
page
session
title and author
abstract
41
HIV/Hepatitis and Other Co-infections
43
The Aging Liver in the HIV Population
D Dieterich
37
43
Co-infection with HCV and HBV: When and How to Treat?
B Polsky
38
44
Antimicrobial Molecules for Treatment of Multi-drug Resistant (MDR) and Extensively Drug Resistant (XDR) Strains of Mycobacterium Tuberculosis
D Miller
39
45
Progressive Multifocal Leukoencephalopathy – A Case Report
M Pop
40
45
Accelerated Approval and Post-marketing Commitments: A Delicate Balance T Swan
41
47
Novel Therapeutic Approaches: Antiviral Mechanism and Predictive Toxicology
49
Optimizing HAART Therapy in the Era of Integrase and Entry Inhibitors
C Katlama
42
50
IDX899 - A Novel Once-a-day Second Generation NNRTI for the Treatment of HIV/AIDS
D Mayers
43
51
Vicriciroc: A Next-generation CCR5 Antagonist for Treatment of HIV
LM Dunkle
44
51
Amdoxovir Combined with Low Dose AZT for HIV-1 Therapy
RL Murphy
45
52
A New Era in HIV-antiretroviral Therapy: Darunavir, Etravirine and TMC278
E Lefebvre
46
53
Low Potential for Class Related Toxicity of Next Generation Nucleotide Analog GS-9148
AS Ray
47
54
Mechanisms Associated with Delayed HIV RT Chain-termination
M Götte
48
55
Acyclovir as an HIV-RT Inhibitor in Herpesvirus-infected Human Tissues
L Margolis
49
56
Comparison of Two Human Pancreatic Cell Lines for Predicting Mitochondrial Toxicity by Nucleoside Analogs
L Bassit
50
xviii
page
session
title and author
abstract
57
ARTEMIS: Efficacy and Safety of Darunavir/ritonavir (DRV/r) 800/100 mg Once-daily vs Lopinavir/ritonavir (LPV/r) in Treatment-naïve, HIV-1-infected
Patients at 96 Weeks
D Jayaweera
51
58
Etravirine (ETR; TMC125) Demonstrates Favorable Efficacy and Safety in the Phase III DUET Trials Regardless of Geographic Location
C Katlama
52
59
Pharmacokinetics and Short-term Safety and Efficacy of Once-daily Etravirine Without and With Once-daily Darunavir/ritonavir in Antiretroviral-naïve
HIV-1 Infected Adults
J Witek
53
60
Activation of Different Cell Death Pathways in Patients on Antiretroviral Therapy with Long-term Viral Suppression but Unfavorable Immunologic
Response
J Blanco
54
61
Safety and Tolerability of the Lopinavir/ritonavir (LPV/r) Tablet in Comparison to other Protease Inhibitors (PIs): The SAPIKAT trial
UF Bredeek
55
62
Analysis of Virologic Endpoints Versus Standard Intent to Treat, in ARTEMIS and TITAN Trials
L Chen
56
63
Improvement of the Transglycosylation Reaction for the Synthesis of β-D-3’-Azido-2’,3’-Dideoxypurine Nucleoside Analogs by Conventional and
Microwave Assisted Heating
S Coats
57
64
The Phtalocyanine Prototype Derivative Alcian Blue: The First Synthetic Agent with Selective Anti-human Immunodeficiency Virus Activity Due to Its
Lectin-like Properties
KO François
58
64
Long-time Virologic Efficacy of Boosted Double Protease Inhibitor Therapy H Knechten
59
65
Etravirine Demonstrates a Favorable Safety and Tolerability Profile at Week 48 in the Pooled DUET Trials Irrespective of Gender, Age, Ethnicity and Weight
E Lefebvre
60
67
Adherence to Darunavir/ritonavir (DRV/r) and Lopinavir/r (LPV/r) in Treatment-naïve HIV Patients in ARTEMIS
E Lefebvre
61
xix
page
session
title and author
abstract
67
Irreversible Pepsin Fraction (IPF) Displays Significant Antiretroviral Activity via Specific Novel Cytokine Stimulation In Vitro Investigation of Activity on
Human Lymphocytes
D Miller
62
68
Successful Use of Dual Therapy with Etravirine and Raltegravir in Patients with HIV Infection
G Pierone
63
69
HIV-1 Co-receptor Use in Heavily Treatment-experienced Spanish Patients
R Sanchez-de la Rosa
64
70
Cost-effectiveness of Maraviroc plus Optimized Background Therapy in Treatment-experienced Patients with R5 HIV-1 in Spain
R Sánchez-de la Rosa
65
71
Once Daily Darunavir/ritonavir: A Single Centre Cohort Experience
C Scott
66
73
Pharmacology and Drug Metabolism
75
Etravirine (ETV, TMC-125) Plasma Levels in Decompensated Liver Disease:
67
A Case Report
M Aboud
75
Virologic Efficacy of Dual-boosted Once-daily (QD) Atazanavir, Fosamprenavir, and Ritonavir (ATV/FPV/RTV): 48 Week Results
UF Bredeek
68
76
A Kinetic Simulation of In Vitro Pharmacodynamics for HIV Drugs HL De Bondt
69
77
Lower Levels of Nucleoside Analog Triphosphates in Primary Human Macrophages Compared to Human Lymphocytes Could Impair Potency of
Antiretroviral Drugs in Human Viral Reservoirs
C Gavegnano
70
78
Lack of Pharmacokinetic Interaction for Low and Normal Dose Zidovudine with Amdoxovir in HIV-1 Infected Individuals
SJ Hurwitz
71
79
Metabolism of Highly Active and Selective 3’-Azido-2’,3’-Dideoxypurine Nucleosides in Primary Human Lymphocytes and MT-2 Cells
A Obikhod
72
xx
Pathogenesis and
Targeted Design
1
Abstract 01
Approaches towards HIV-1
Eradication: Harnessing Cellular
Restrictions
M Stevenson
University of Massachusetts Medical School, Worcester,
MA, USA
The replication of primate lentiviruses is dependent
upon their ability to commandeer cellular factors
at various stages in the replication cycle. Research
over the past several years however, has revealed
the presence of “cellular restrictions” that potently
antagonize viral replication. For example, the Apobec
3 proteins are cytidine deaminases that compromise
the formation and integrity of viral cDNA while Bst2/
tetherin prevents detachment of budding viruses
from the surface of the infected cell. In order to
counteract these restrictions, primate lentiviruses
have evolved accessory proteins: the Vif protein
targets Apobec 3 for proteasomal destruction while
Vpu mislocalizes Bst2/tetherin away from sites of
virus budding. We have recently obtained evidence
for a novel restriction that is expressed in cells
of macrophage lineage. This restriction potently
antagonizes the replication of primate lentiviruses
including HIV-1/2 and SIV as well as retroviruses
such as MLV. We have evidence that this restriction
is counteracted by the viral accessory proteins Vpx/
Vpr. These proteins commandeer a damaged DNA
response protein (DDB1) to target the restriction to
the proteasome. We have further obtained evidence
that this restriction dictates the cell cycle dependence
of lentivirus and retrovirus infection. Therefore when
the restriction is neutralized, macrophages, which are
normally refractory to MLV infection, are rendered
permissive to MLV transduction. With a view to
targeting accessory proteins for drug discovery, we
have identified small molecule inhibitors of HIV-1
Vif. These Vif antagonists exhibit antiviral effects only
in cells that express Apobec 3 proteins and increase
the extent of cytidine deamination in nascent viral
cDNA. Given our increasing understanding of the
function of the viral accessory proteins, they remain
highly attractive targets for therapeutic intervention
in HIV/AIDS.
Abstract 02
Understanding HIV Maturation
using Electron Cryotomography
ER Wright1, JB Schooler1, HJ Ding1, C Kieffer2,
C Fillmore2, WI Sundquist2, and GJ Jensen1
1 Division of Biology, California Institute of Technology,
Pasadena, CA, USA; 2 Department of Biochemistry,
University of Utah, Salt Lake City, UT, USA
BACKGROUND: HIV maturation is a dynamic process,
which occurs once the virus buds and is released from
the infected cell. The unprocessed Gag polyprotein
is composed of polypeptide segments, termed MA,
CA, SP1, NC, SP2, and p6 that are arranged radially,
with the N-terminal MA region at the membrane
and the C-terminal NC-SP2-p6 region nearest the
center [1, 2]. Maturation involves the proteolytic
processing of Gag and Gag-Pol polyproteins by
protease (PR). During maturation, MA remains
bound to the membrane, while the processed CA
subunits condense to form a central conical capsid
that encases NC, the RNA genome, and other viral
enzymes. The structures of nearly every component
of HIV have been determined, but it is still unclear
how individual subunits come together to form the
intact virion. We are studying the maturation process
of HIV-1 by electron cryotomography (cryo-ET) in
order to understand the structural changes that occur
within the virus.
METHODS: HIV-1 virions were made non-infectious
and/or halted in the immature state by the inactivation
of the proteins PR, RT, and RNase H [3, 4]. Solutions
of the purified HIV-1 virions were flash-frozen onto
EM grids in liquid ethane. The frozen-hydrated grids
were imaged in a 300 kV “G2 Polara” FEI TEM under
low dose conditions. Single and dual-axis tilt series
were collected using the predictive UCSF tomography
package [5]. All images were energy-filtered, recorded
3
with a defocus ranging from -4 to -8 μm, and with
CCD pixels representing 0.46 or 0.56 nm on the
specimen. Images were binned by a factor of 2, and
three-dimensional reconstructions of the virions
were calculated with IMOD [6]. Individual virions
were selected and denoised by non-linear anisotropic
diffusion in the BSOFT program [7, 8]. Additional
processing and analysis steps were performed using
either the Amira software package (Visage Imaging,
Inc.) or UCSF Chimera [9].
RESULTS: The capsid of the mature virus can have
numerous morphologies, the most common being a
somewhat asymmetrical cone. Cryo-ET examinations
of mature HIV-1 virions revealed that the conical
cores were unique in structure and position (Fig. 1),
but they also demonstrated certain similarities with
respect to size and shape, the distance of the cone’s
base from the envelope/MA layer, the range of the
cone angle. It was also observed that the conical capsid
shape was preferred in vivo, which argues in favor
of the template-directed model of capsid formation
[4]. Examinations of immature virions revealed the
concentric shells of the Gag polyprotein (Fig. 1). Upon
further analysis, only the CA and SP1 shells contained
patches of hexagonal order. Averaging well-ordered
unit cells led us to propose a model for the immature
lattice in which each CA hexamer is stabilized by a
bundle of six SP1 helices (Fig. 2).
References:
[1] S. D. Fuller et al., Curr. Biol. 7 (1997) 729.
[2] T. Wilk et al., J. Virol. 75 (2001) 759.
[3] D. J. Wyma et al., J. Virol. 74 (2000) 9381.
[4] J. Benjamin et al., J. Mol. Biol. 346 (2005) 577.
[5] Q. S. Zheng et al., J. Struct. Biol. 147 (2004) 91.
[6] J. R. Kremer et al., J. Struct. Biol. 116 (1996) 71.
[7] J. B. Heymann, J. Struct. Biol. 133 (2001) 156.
[8] A. S. Frangakis and R. Hegerl, J. Struct. Biol. 138
(2002) 105.
[9] E. F. Pettersen et al., J. Comput. Chem. 25 (2004)
1605.
4
Fig 1. Tomographic reconstruction of two isolated HIV-1 virions
(top, immature; bottom, mature) preserved in vitreous ice. Scale
bar 100 nm.
Fig 2. Model for the roles of Gag subunits in the immature and
mature lattices. Top and side views (top and bottom, respectively)
of low-pass filtered atomic models of the immature (left) and
mature (right) lattices. Scale bar 8 nm.
Abstract 03
Vpu and Its Cellular Targets
P Spearman, J Hammonds, S Ali, D Shaw, L Ding, and
JJ Wang
Emory University School of Medicine, Atlanta, GA, USA
BACKGROUND: Vpu is a small accessory protein
that functions in the downregulation of CD4
and enhances particle release. The mechanism by
which Vpu enhances particle release has remained
mysterious until recent years, when it was shown
that there is a dominant host cell restriction in many
human cells that is not present in simian cells. In the
past year, tetherin (BST2, CD137) has been identified
as the molecule responsible for particle tethering at
the plasma membrane of cells. Calcium modulating
cyclophilin ligand (CAML) was also identified by our
group as a host restriction factor overcome by Vpu.
Additional studies are uncovering the mechanism of
action of these restriction factors, and should provide
insights into how host restriction may be turned to
therapeutic advantage.
METHODS: We identified CAML as a direct interactor
of Vpu by yeast 2-hybrid screen, and confirmed
the interaction by co-immunoprecipitation from
mammalian cells. African green monkey CAML
was then cloned from Cos-7 cells, sequenced, and
expressed for comparisons with human CAML.
Tetherin was expressed from its cDNA in tagged form.
Both CAML and tetherin were analyzed for the ability
to restrict particle release, using p24 antigen assay,
Western blot, and electron microscopy as endpoints.
The subcellular distribution of both molecules in the
presence or absence of Vpu was compared using laser
confocal fluorescence microscopy.
RESULTS: Both CAML and tetherin restricted particle
release, and were able to convert permissive cells to a
restrictive phenotype. Tetherin was more potent in
this effect on the basis of amount of cDNA required
in transfection to confer restriction. Overexpression
of either molecule resulted in a particle tethering that
was apparent by electron microscopy. Tetherin more
dramatically colocalized with Vpu in coexpression
studies, and Vpu redistributed tetherin from the
plasma membrane to intracellular sites. An African
green monkey CAML molecule failed to confer
restriction, and the difference in function of human
and AGM CAML was mapped to a single residue
change in the cytoplasmic domain.
CONCLUSIONS: Vpu overcomes host cell restriction
that is characterized by particle tethering at the
membrane. Therapeutic strategies that target Vpu
would result in a potent block to viral replication
occurring after viral budding.
Abstract 04
Cell Penetrating Peptides:
From Molecular Mechanisms to
Therapeutics
A Agopian1, E Gros1, P Clayette2, MC Morris1,
G Aldrian-Herrada1, and G Divita1
1 CRBM, CNRS, UMR5237, Montpellier, France;
2 SPI-BIO CEA, Fontenais aux roses, France
The rapid emergence of drug-resistant viruses against
approved drugs together with their side effects limits
the potency of existing anti-HIV-1 therapeutics.
Therefore, there is an urgent demand for new and
safer drugs and extensive efforts have been made
in the design of molecules that specifically target
protein/protein interfaces required during HIV-viral
replication. Nowadays, delivery constitutes a major
piece of the therapeutic puzzle, and the success of
future therapies requiring large molecules will be
conditioned by access to potent delivery systems.
With the aim of designing specific antiviral molecules,
we have validated a new concept that combines
peptide-based nanoparticle delivery system with
short peptides that target protein-protein interfaces
required for reverse transcription.
The whole process of reverse transcription is driven
by different protein/protein interactions involving
mainly reverse transcriptase (RT). RT is a heterodimer
p51/p66, each consisting of distinct sub-domains:
fingers, palm, connection, thumb and RNAse H,
the latter only present in p66. The formation of
the biologically active RT is a two-step mechanism,
including a rapid protein/protein interaction
“dimerization”, followed by conformational changes
“maturation”. We have designed two families of short
peptides targeting either dimerization or maturation
steps. Pep-71 (9-mer) derived from the Trp-rich
cluster of the connection subdomain blocks RTdimerization. Pep-71 interacts preferentially with
Trp24 and Phe61, in a cleft between the connection
and fingers domains of the small p51 within
5
heterodimeric-RT, and destabilizes the dimeric
conformation, thereby triggering dissociation. Paw
(15-mer) derived from the thumb domain prevents
the dynamics of the fingers/thumb domains of p66,
thereby inhibiting maturation of heterodimeric-RT
and its association with Integrase. In order to evaluate
these inhibitors in vivo, we have developed a peptidebased nanoparticle-system NANO-VEPEP, which
forms stable complexes with peptides and improves
their cellular uptake, as well as their in vivo stability/
biodistribution. NANO-VEPEP particles can be
functionalized, which constitutes a major advantage
for in vivo targeting. When delivered into cells using
NANO-VEPEP, both Pep-71 and Paw dramatically
abolish replication of HIV-1LAI with IC50 of 0.5 and
0.32 nM respectively, and a selectivity index of about
4000. Moreover, sub-nanomolar concentrations of
both peptides block the replication of either multidrug resistant strains or primary HIV isolates from
subtypes A to G. Preliminary evaluation of Pep71 in an HIV susceptible transgenic rat model has
confirmed the potency of the NANO-VEPEP-Pep-71
particles in vivo.
We have established a proof-of-concept that targeting
conformational changes required for RT flexibility
can lead to highly potent specific new antiviral drugs
that can bypass resistance limitation. We believe that
combining large molecules with modulable delivery
systems will provide new perspectives for inhibitors
of the “niche” of highly resistant strains and more
generally raise new hope for more specific drugs to
reach clinical evaluation.
Abstract 05
Foot Fractures in HIV-infected
Patients Previously Treated with
Tenofovir (TDF)- versus NonTDF-containing Highly Active
Antiretroviral Therapy (HAART)
R Joseph1, A Horizon1, Q Liao2, S Ross2, and G Pakes2
1 Cedars-Sinai Health System, Los Angeles, CA, USA;
2 GlaxoSmithKline, Research Triangle Park, NC, USA
BACKGROUND:
Among HIV-infected patients,
osteopenia has been reported in 22-50% and
osteoporosis in 3-21%. Both conditions notably
increase the risk of bone fractures, especially of hip and
spine. However, little is known about the incidence of
foot fractures in HIV-infected patients or about the
association of particular antiretroviral drugs in the
pathogenesis of these fractures. We characterized
foot fractures diagnosed in HIV+ patients in the Los
Angeles Cedars-Sinai Health System.
METHODS: In this retrospective case series study,
medical records of all male HIV-infected patients
with MRI-confirmed foot fractures (n=30) were
examined.
Data regarding demographics, HIV
history, co-morbidities, HAART/non-HIV drug
prescription history, DEXA bone mineral density
scores, and fracture type were collected on Excel
sheets and analyzed by logistic regression with
stepwise selection.
RESULTS: Proportionally more foot fracture patients
had received TDF-containing HAART (17 [57%])
than non-TDF-containing HAART (13 [43%]) prefracture. At fracture diagnosis, these 2 groups
were similar regarding median age (49y/48y), HIV1RNA (both 1.7 log10c/mL), time between HIV
diagnosis and foot fracture (both 17.0y); incidence
of metatarsophalangial fracture (12%/15%) and
vertebral fracture (12%/15%); family history of bone
diseases (24% vs 23%); frequency of malabsorption
syndrome, renal failure, calcium deficiency, and vitamin
D deficiency; and concurrent use of bisphosphonates
6
(65%/69%), calcitonin, and diuretics. However, the
TDF-treated group had more osteoporosis (35%/8%),
stress-type fractures (53%/31%), other concurrent
fractures (12%/0%), wasting syndrome (29%/15%),
centripetal obesity (18%/8%), chronic cigarette
smoking of >1pack/day (35%/8%), DEXA T-scores
<-2.4 (denoting osteoporosis) in femur (24%/9%)
and spine (47%/36%), and a lower frequency of
alcoholism (12%/31%) and anemia of chronic
disease (0%/23%). More TDF-treated patients
concurrently received protease inhibitors (71%/46%),
NNRTIs (24%/0%), prednisone (24%/0%), calcium
supplements (100%/85%), vitamin D (100%/85%),
testosterone (47%/23%), and teriparatide (29%/8%).
Median time from TDF initiation until fracture was
2.57y (range,1.17-5.69y). Logistic regression analysis
showed relationships between femur DEXA T-scores
<1.5 and body weight (p=0.036) and serum glucose
(p=0.034).
CONCLUSIONS: This small pilot study suggests a
greater incidence of foot fractures in HIV-infected
patients on TDF- than non-TDF-containing HAART.
Co-morbidities and/or co-administered drugs may
have influenced the occurrence of these fractures.
7
Toward HIV Eradication
9
Abstract 06
Complementary Mechanisms of
Nucleoside Analog Resistance
from Structural Studies of HIV-1
Reverse Transcriptase
E Arnold1,2, K Das1,2, X Tu1,2, R Bandwar1,2,
S Sarafianos1,2, S Tuske1,2, AD Clark, Jr.1,2, J Bauman1,2,
PL Boyer3, Q Han2, B Gaffney2, RA Jones2, K White4,
J Feng4, M Miller4, and SH Hughes3
1 Center for Advanced Biotechnology and Medicine;
2 Rutgers University Department of Chemistry and
Chemical Biology, Piscataway, NJ, USA; 3 NCI Drug
Resistance Program, Frederick, MD, USA; 4 Gilead
Sciences, Foster City, CA, USA
Nucleoside inhibitors (NRTIs) of HIV-1 reverse
transcriptase (RT) are among the most important antiAIDS drugs and are prescribed in nearly all treatment
regimens. We have used X-ray crystallography to
study the structural basis for the mechanisms of
resistance to AZT (zidovudine) and PMPA (tenofovir).
A detailed understanding of the distinct mechanisms
of resistance to the two drugs and their antagonistic
relationship is critical for understanding the
complexity of NRTI resistance and for designing new
and broadly effective NRTIs.
Resistance of HIV-1 RT to AZT has been shown to
involve an ATP-mediated excision reaction in which
AZTMP is removed from the terminated primer,
forming a dinucleoside tetraphosphate product,
AZTppppA. We have solved and analyzed a series of
AZT-resistant HIV-1 RT structures, including ternary
complexes with a template-primer and the excision
product AZTppppA. The structures define the roles
played by the major AZT-resistance mutations in the
mechanism of AZT resistance. Primary mutations
K70R and Y215Y help in binding the ATP molecule
to the mutant RT and therefore can be classified as
excision-enhancing mutations (EEMs).
The mutation K65R causes resistance to tenofovir and
has complex relationships with other NRTI-resistance
mutations. We have analyzed structures of K65R HIV1 RT in ternary complexes with tenofovir diphosphate
and dATP. We propose that differential stacking of
the guanidinium groups of K65R and R72 creates
a “checkpoint” that reduces dNTP incorporation
and allows the mutant RT to discriminate between
tenofovir diphosphate and the normal substrate,
dATP. The structural results also suggest potential
mechanisms of complex relationships of K65R
mutation with other NRTI-resistance mutations
including the antagonistic relationship with EEMs.
Abstract 07
Dose Response Curve Slope Sets
Class Specific Limits on Inhibitory
Potential of Anti-HIV Drugs
L Shen1, S Peterson1, AR Sedaghat1, MA McMahon1,
M Callender1, H Zhang1, Y Zhou1, KS Anderson2,
EP Acosta3, and RF Siliciano1, 4
1 Johns Hopkins University School of Medicine,
Baltimore, MD, USA; 2 Yale University School of
Medicine, New Haven, CT, USA; 3 University of Alabama
at Birmingham School of Medicine, Birmingham, AL,
USA; 4 Howard Hughes Medical Institute, Baltimore, MD,
USA
Background: Preventing disease progression
for HIV-1 infected patients requires regimens that
maximally suppress virus replication. A comparative
measure of antiviral activity under clinically relevant
conditions would guide drug development and regimen
selection but is currently lacking. We hypothesized
that the slope parameter (or Hill coefficient), which
is neglected in current measures of antiviral activity,
might have a dramatic effect on antiviral activity of
anti-HIV-1 drugs. To account for the effect of slope,
we developed a new index, instantaneous inhibitory
potential (IIP), as a new in vitro measure of antiviral
activity.
Method: A single round infectivity assay with wide
dynamic range in primary CD4+ lymphoblasts was
used to obtain dose response curves for anti-HIV-1
11
drugs. IC50 and slope parameters were determined
by fitting the curves into the median effect model
with least square regression analysis. IIP equals the
number of logs by which single round infectivity is
reduced at clinically relevant drug concentrations and
was calculated based on the median effect equation.
Result: We show that current measures of antiviral
activity, IC50 and inhibitory quotient, neglect a
critical dimension - the dose response curve slope,
which has a dramatic effect on antiviral activity.
Strikingly, slope values are class-specific for antiviral
drugs and define intrinsic limitations on antiviral
activity for some drug classes. Nucleoside reverse
transcriptase inhibitors and integrase inhibitors
have slopes of ~1, characteristic of non-cooperative
reactions, while nonnucleoside reverse transcriptase
inhibitors, protease inhibitors, and fusion inhibitors
unexpectedly show slopes >1. IIP is strongly
influenced by slope, varies by >8 logs for current
anti-HIV drugs and provides a more accurate in vitro
pharmacodynamic measure of antiviral activity than
traditional IC50 or inhibitory quotient measures.
Conclusion: Antiretroviral drugs acting through
different mechanisms have different value for the
slope parameter which has crucial influence on
antiviral activity under clinically relevant conditions,
as reflected in IIP. Only agents with slopes >1 achieve
high level inhibition of single round infectivity, a
finding with profound implications for drug and
vaccine development.
Abstract 08
Pharmacology, Metabolism and
Transport of HIV Drugs into Viral
Reservoirs
S Khoo
University of Liverpool, UK
Failure of antiretroviral therapy (ART) to suppress
viral replication within a reservoir of HIV infection
12
establishes a sanctuary. These sanctuaries arise in
part because of physiochemical characteristics of
drugs which limit their penetration into cells and
tissue compartments, and also because of anatomical,
biochemical and physiological barriers inherent to
compartments. The brain and testes are recognised
sanctuaries where discordance in viral load or viral
quasispecies may arise in some individuals (although
in most individuals, viral kinetics mimics that of
peripheral blood). PIs (being lipophilic and highly
protein bound) are most likely to be affected by
processes which establish drug sanctuaries, and
NRTIs least (although differences exist within this
class). Significant differences have also been observed
between nevirapine and efavirenz, with the latter
accumulating to a lesser degree within brain and
genital tract. Accumulating evidence also points
to possible sanctuaries within the female genital
tract, breast milk and placenta. The evidence for
drug sanctuaries within cellular subsets is much less
strong- due in large part to technical difficulties that
these studies have encountered.
A hierarchy of intracellular accumulation of HIV
PIs has been observed but the clinical relevance is
uncertain. Major questions remain around localisation
(cell membrane-associated, or truly intracellular?) and
intracellular free fraction of drug. Whilst the major
determinants of this hierarchy are the physiochemical
characteristics of PIs (lipophilicity, protein binding),
the large inter-individual variability observed may
be in part due to differences in drug transporters.
Transporters may not only affect drug disposition
in gut, liver and kidney, but also within anatomical
compartments and cells. PIs are substrates for efflux
(ABCB1, ABCC1/2, ABCG) transporters and recent
data suggest they may also be substrates for influx
(SLCO 1A2, 1B1) transporters. N(t)RTIs also undergo
carrier-mediated transport (ABCC4/5; hCNT, hENT).
The clinical relevance of these findings to drug
sanctuaries depends on cell surface expression of
these molecules within specific tissues, and also
pharmacogenetic variability which may alter drug
disposition between individuals. Although the
liver and gut are major sites of drug metabolism by
cytochrome P450 enzymes, some P450 isoforms may
also be present within the cytosol of PBMCs, adding
another dimension of complexity to the study of
intracellular pharmacology.
New generations of existing classes, and new classes
of anti-HIV compounds increase opportunities for
maximising penetration of all components of the
regimen into sanctuaries. Conventional clinical trial
endpoints lack sensitivity to tease out differences in
regimen potency outside of plasma, and although the
effects of drug sanctuaries may not be immediately
apparent, the fact that they exist at all gives cause for
concern.
Abstract 09
Immunotoxins to Selectively
Deplete Reservoirs of HIVinfected Cells that Persist in
the Face of Highly Suppressive
Antiretroviral Therapy
EA Berger1, PE Kennedy1, TK Bera2, M Gallo2, and
I Pastan2
1 Laboratory of Viral Diseases, NIAID; 2 Laboratory of
Molecular Biology, NCI, NIH, Bethesda, MD, USA
Background: Highly sensitive assays have
revealed the presence of extremely low levels of
HIV-1 RNA in plasma despite highly suppressive
HAART. This residual viremia is non-evolving, does
not accumulate additional drug resistance mutations,
and is non-responsive to intensification with new
therapeutic agents targeting additional steps in the
virus replication cycle. These findings have raised the
notion that the residual viremia might come from
long-lived productively infected cells, perhaps capable
of proliferation. If true, this model would suggest
the importance of therapeutic regimens aimed at
selectively killing the HIV-producing cells that persist
in the face of HAART.
Methods: We have developed immunotoxins
targeted to the HIV-1 Env as an approach to deplete
infected cell reservoirs persisting after HAART. Each
immunotoxin is a recombinant single-chain chimeric
protein containing the translocation and cytotoxic
domains of Pseudomonas aeruginosa exotoxin A linked
to a specific protein that binds Env. The first agent
(CD4-PE40) employs sCD4 as the Env-targeting
moiety; a newer, more potent agent (3B3-PE38)
employs an SCFv of the high affinity 3B3 MAb against
the highly conserved CD4 binding site.
Results: Each protein killed chronically HIVinfected cells with very high potency (IC50 ≈ 2 nM for
CD4-PE40, 0.03 nM for 3B3-PE38), while showing
negligible activity against the uninfected parental
cells. Each protein inhibited spreading infection by
diverse primary HIV-1 isolates in both PBMCs and
primary macrophages; again 3B3-PE38 proved more
potent than CD4-PE40. Combined treatment of
acutely infected T cell cultures with toxin plus an RT
inhibitor completely eliminated infectious virus, a
result not achieved with either agent alone. Similarly
in collaborative studies using a murine model, HAART
alone strongly suppressed HIV-1 replication, but the
viral load rebounded after treatment was stopped;
when an immunotoxin was included with HAART
during the treatment phase, viral rebound was not
observed after treatment cessation. These results
highlight the particular value of combining HAART
drugs that block HIV replication with immunotoxins
that kill already-infected cells. Collaborative
experiments have demonstrated immunotoxin
efficacy in combination with activating agents that
induce HIV expression from latently infected cells. In
rhesus macaques, high levels of CD4-PE40 displayed
some hepatotoxicity, in keeping with the dose-limiting
hepatotoxicity observed in earlier Phase I trials in the
pre-HAART era. By contrast, high levels of 3B3-PE38
displayed no hepatotoxicity in macaques, consistent
with recent human clinical trial results with anticancer PE-based immunotoxins that have induced
major remissions of leukemias and lymphomas
without serious liver toxicity.
Conclusion: These results suggest that Envtargeted immunotoxins might prove critical for
depleting the HIV-infected cell reservoirs persisting
in the face of HAART. Clinical trials are planned
13
to evaluate whether combining such agents with
suppressive HAART might deplete infected reservoirs
sufficiently to enable prolonged cessation of therapy
without viral rebound.
Abstract 10
Development of Pyrimidinedione
NNRTIs with a High Genetic
Barrier to Resistance
RW Buckheit Jr., TL Hartman, L Yang, and KM Watson
ImQuest BioSciences, Frederick, MD, USA
With the increasing incidence of HIV drug-resistant
viruses in the HIV-infected population, it is critical
that a new generation of highly safe and potent drugs
be developed to address this issue. Within the NNRTI
class of inhibitors, the dual-acting pyrimidinediones
offer an opportunity to provide a new alternative for
both HAART and salvage therapy regimens. Among
a SAR series of 68 pyrimidinedione compounds, a
number were found to potently inhibit viruses with
typical NNRT-resistance engendering mutations,
such as Y181C, L100I, and K103N, in both cell-based
and biochemical RT inhibition assays, suggesting
that the molecules may interact with the binding
pocket in a manner which would result in a higher
genetic barrier to resistance. In addition, the series
of compounds possess wild type levels of activity
when tested against multi-drug resistant viruses
obtained from patients failing prolonged courses of
RT and PI therapies. In order to further evaluate this
hypothesis, viruses resistant to the antiviral effects
of the lead compounds were selected in cell culture
using both serial dose escalation and fixed dose
resistance selection methods, as well as through the
evaluation of the activity of the pyrimidinediones
against biologically selected and site-directed viruses
with defined NNRTI-resistance mutations. These
studies confirmed that the pyrimidinediones required
the accumulation of multiple mutations in the RT in
order to develop high level NNRTI resistance. Further
mutations in envelope and/or core HIV-1 proteins
14
were required in order to achieve complete resistance.
Antiviral assays with drug resistant and multi-drug
resistant viruses indicated that the compounds
were able to effectively inhibit viruses with NNRTIresistance mutations and exhibited enhanced
sensitivity to multi-drug resistant viruses obtained
from patients failing long courses of PI therapy as well
as RT/PI therapy. Additional studies were performed
with NNRTI- resistant viruses with the entire SAR
series of molecules in an effort to define molecules
with specific capability of inhibiting highly resistant
viruses such as those with the Y181C, L100I, K103N
(alone and in combination) as well as with MDRs with
resistance phenotypes/genotypes to RT inhibitors,
PI inhibitors and both RT and PI inhibitors. These
molecules now represent leads for the continued
development of a new SAR to identify clinical
candidates with extremely high genetic barriers to
resistance. The results of our in vitro studies would
indicate that the pyrimidinediones possess a high
genetic barrier to resistance based on both their dual
mechanism of action as well as their low intrinsic
level of resistance to individual RT amino changes.
Their activity against MDRs suggests the compounds
may be highly effective in primary or salvage therapy
regimens.
Abstract 11
Development of VS411, a
Virostatic Drug Fixed Dose
Combination (FDC) Designed to
Inhibit both HIV and Immune
Hyperactivation
F Lori and M Stevens
ViroStatics Srl, Sassari, Pavia, Italy, and Princeton, NJ,
USA
BACKGROUND: No available anti-HIV product is
designed to down-modulate the immune system
hyperactivation now recognized as a key component
of HIV/AIDS pathogenesis and disease progression.
METHODS: VS411, a two-drug FDC, is designed
to suppress HIV both directly and indirectly: one
drug interferes with HIV reverse transcription, the
other decreases availability of HIV natural targets
(activated/proliferating T-cells) thus reducing the
growth rates of wild-type viruses and drug-resistant
escape mutants. This novel class of anti-HIV drugs
has been named “virostatics” (antiviral+cytostatic).
We have concluded a pilot Phase I (12 individuals),
open label, randomized, single dose, 4-way crossover
trial investigating the fasted and non-fasted oral
bioavailability of didanosine (ddI) and hydroxyurea
(HU), co-formulated and administered as two different
FDC formulations, with the goal of decreasing
ddI Cmax compared to commercially available ddI
beadlets. An ongoing Phase II, multinational dosefinding study is exploring decreasing both HU and
ddI dosages in 60 chronically infected, drug-naïve
patients.
RESULTS: VS411 has been designed as a QD capsule
containing both an antiviral (ddI) and a cytostatic
(HU) compound with synergistic HIV-suppressing
activity. Phase I study results indicated 30% lower
Cmax and similar AUC of ddI for both the VS4112 and VS411-4 test formulations compared to the
commercial ddI formulation. The test formulations’
HU Cmax and AUC were virtually identical to
commercial HU. As the absorption of ddI was less
predictable for the VS411-4 formulation and intersubject variability of ddI concentrations was higher,
the VS411-2 formulation was selected for further
development. Food significantly decreased ddI and,
unexpectedly, HU exposure, and increased intersubject variability. Since randomized, controlled
clinical studies using the two components of VS411
in separate pills administered simultaneously have
indicated that decreasing the hydroxyurea dose by
50% reduced the incidence of previously observed
toxicity by 40% while preserving antiviral efficacy,
the Phase II study explores decreasing the HU dosage
to as little as 300 mg daily, 3- to 5 fold less than
previously explored in HIV-infected individuals, and
ddI dosage to as little as 200 mg daily, 2-fold less than
routinely used. New experiments confirmed previous
results identifying the G1/S (activation/commitment
to division) phase transition checkpoint as the cell
cycle progression point that is critical for maximal
HIV-1 replication. By limiting, without blocking, cell
cycle progression through this checkpoint both cell
proliferation and viral replication were significantly
restricted, supporting the use of cytostatic drugs in
HIV-infected individuals.
CONCLUSIONS: VS411 represents the first drug
combination targeting both components (HIV
replication and immune system hyperactivation)
responsible for disease progression. A VS411 capsule
has been formulated for QD administration. A Phase
I VS411 study supported QD administration and met
the goal of lowering ddI Cmax while retaining total
drug exposure. An ongoing Phase II, dose-finding
VS411 study is exploring decreasing both HU and ddI
dosages.
Abstract 12
Inhibiting Vpu Function with
the Novel Compound BIT225,
Results in Inhibition of HIV-1
Release from Human Macrophage
Reservoirs
G Khoury1, G Ewart2, C Luscombe2, M Miller2 and
J Wilkinson1
Biotron Limited, 1 Centre for Immunology, St Vincent’s
Hospital; 2 Suite 1.9, 56 Delhi Road, North Ryde, Sydney,
Australia
Background: Biotron Limited is focused on the
development of inhibitors for two viroporins; Vpu
(HIV-1) and p7 (HCV). Our lead compound, BIT225,
demonstrates good anti-HIV-1 activity (IC50=1.1±0.4
µM) with minimal cellular toxicity in macrophages
(Mφ). Cells of the monocyte lineage are key reservoirs
of HIV-1 and disseminate virus to the peripheral
tissues. Here we further define the extent of BIT225’s
novel antiviral activity that may represent a new class
of antiviral therapeutics.
15
Methods: Monocytes isolated from seronegative
donors were infected with HIV-1 or HIV-2 (No vpu) at
day 14 of Mφ differentiation. Antiviral activity with
BIT225 was determined in both ‘acute’ (HIV-1BaL at
MOI of 0.05 for 3h) and ‘chronic’ (7d infection prior
to treatment) infection assays. Virus was quantitated
using real-time PCR, reverse transcriptase activity and
the indicator cell line TZMb1. Additionally, samples
were processed for confocal and electron microscopy
and protein analysis by western blot.
Abstract 13
Results: BIT225 at 10 uM resulted in >99% inhibition of HIV-1 integration and >95% inhibition of
HIV-1 release in our acute assay and >92% inhibition
of virus release in our chronic assay. Additionally, in
co-culture BIT225 significantly inhibits HIV-1 transfer
from Mφ to more permissive CD4+ T cells. Supporting
our initial anti-vpu drug-screening program, BIT225
demonstrated no antiviral activity on two HIV-2
strains, HIV-2CBL-20 (rapid) and HIV-2CBL-23 (slow);
further suggesting the activity is targeted against the
vpu accessory protein of HIV-1. Infecting TZMbl’s
in the presence of BIT225 confirmed that BIT225
activity occurs post-integration. Unlike RT inhibitors,
infection was not inhibited by BIT225, which was
comparable to protease inhibitor activity. Similarly,
BIT225 had no direct affect upon the HIV-1 RT or
protease enzymes further alluding to a novel mode
of action. Visualisation of HIV-1 de novo synthesis
by EM demonstrated that Mφ treated with BIT225
resulted in a morphological appearance suggestive of
abnormal packaging compared to that of the control.
Characterisation of these abnormalities has begun
through preliminary protein analysis.
Merck Research Labs, West Point, PA, USA
Conclusions: This study shows that BIT225 is a
late-phase inhibitor that significantly inhibits HIV1 release from human Mφ’s. BIT225’s activity is not
directed at the HIV-1 enzymes RT or protease with
evidence to date suggesting its antiviral activity is
via vpu. The abnormal morphology observed by EM
within the intracellular compartments hints toward a
mechanism of action.
16
Integrase Inhibitors: New
Insights into Mechanism of
Action and Pharmacology with
Implications for Treatment and
Prevention Strategies
D Hazuda for the HIV Drug Discovery Team
With the approval of raltegravir in 2007, integrase
inhibitors now offer an entirely new option for
the treatment of HIV-1 infection. An increased
understanding of this class is important to maximize
their clinical utility and drive future drug discovery
and development efforts.
Studies by us as well as others have recently suggested
that the mechanism of action inhibitors such a
raltgravir which affect integrase strand transfer
activity may offer a unique advantage over other
ARVs. Because these inhibitors bind to the enzyme
after reverse transciption and formation of the preintegration complex, they are fully effective in cell
culture even when addition is delayed for as a long
as eight to ten hours following infection. Moreover,
raltegravir and “second generation” molecules which
have been selected for their ability to inhibit resistant
variants have a long residence time on the integrase/
DNA complex. While the off rate of different
integrase inhibitors can range from several hours to
days, in many cases this exceeds the half life of the
pre-integration complex resulting in a functionally
irreversible inhibition of integration and HIV-1
infection in cells. For raltegravir, in particular, these
properties likely contribute to the observation that
efficacy is not linked to trough concentrations in vivo.
These insights into the mechanism of action and
unique intracellular pharmacology of these agents
have important implications for understanding
the clinical pharmacology of this class and suggest
integrase inhibitors could play an important role
in eradication strategies as well as post-exposure
prophylaxis to prevent the acquisition of HIV-1
infection.
Abstract 14
A Non-human Primate Model for
Development of AIDS Eradication
Strategies
TW North, J Higgins, J Deere, TL Hayes, A Villalobos,
LA Adamson, BL Shacklett, and PA Luciw
University of California, Davis, CA, USA
BACKGROUND: The long-term goal of this project is
to develop and evaluate strategies for eradication of
HIV-1 from infected individuals. These studies will
be performed with an animal model that enables
comprehensive analyses of viral reservoirs and
replication dynamics during HAART. This model
utilizes rhesus macaques infected by a chimeric
virus of SIVmac239 containing the HIV-1 reverse
transcriptase (RT) in place of the SIV RT (RT-SHIV).
METHODS: In order to study eradication strategies
in the RT-SHIV/macaque model, we have developed
a sensitive virus load (VL) assay with a limit of
detection of 1-2 copies of viral RNA (vRNA) per ml
of plasma, and have also developed sensitive RT-PCR
and PCR assays to measure vRNA and viral DNA
(vDNA) in tissues. These methods have been used for
a comprehensive analysis of RT-SHIV RNA and DNA
in tissues, cells and fluids of infected macaques. For
this study, nine HAART-treated macaques were used
for analyses of cells and tissues collected at necropsy
(5 macaques), and for rebound of VL after cessation
of therapy (4 macaques).
RESULTS: In this model a three-drug combination
that is widely used in humans (efavirenz + FTC +
PMPA) mimics HAART in HIV-1-infected individuals
with respect to virus load (VL) suppression and rebound
upon cessation of drug therapy. A comprehensive
analysis of 28 different tissues collected at necropsy
from a no-drug control and five HAART-treated, RTHIV DART 2008 - Frontiers in Drug Development for Antiretroviral Therapies
SHIV-infected macaques was completed. Viral DNA
and RNA were detected in nearly all tissues of the
control macaque examined including all lymphoid
tissues, all regions of the gastrointestinal (GI) tract,
several sites from brain and genital tissues. In the
HAART-treated animals we detected RT-SHIV DNA
and RNA in lymphoid tissues from all five of the
animals. RT-SHIV DNA was detected in the thymus
from all 5 HAART-treated animals, but vRNA was
detected in only three. RT-SHIV DNA was detectable
in most of the GI tissues from all HAART-treated
animals, but vRNA was less prevalent (undetected in
some samples) and was lower than in lymph nodes.
In all other tissues, RT-SHIV RNA and DNA were
undetectable or very low in HAART-treated macaques.
Resting CD4+ T-lymphocytes obtained from spleen,
lymph nodes, jejunum and PBMC had higher levels of
RT-SHIV DNA than total cell suspensions from which
they were obtained.
CONCLUSIONS: These studies have identified
potential sites of virus replication and latency during
suppressive HAART. This model will be useful for
determination of the relative contributions of residual
replication and latency to residual viremia during
HAART. It will also be valuable for testing eradication
strategies to eliminate residual replication and/or
reactivate latent virus during HAART.
Abstract 15
Diminution of HIV Latency
through Blockage of Arginine
Methylation of Viral Proteins
MA Wainberg, CF Invernizzi, S Rita, S Schildknecht,
S Colby-Germinario, K Dahl, B Spira, and
BG Brenner
McGill University AIDS Centre, Jewish General Hospital,
Montréal, Québec, Canada
Background: We have shown that the HIV-1
proteins Tat, Rev, and NC are substrates for protein
arginine methyltransferase 6 (PRMT6). Such arginine
17
methylation interferes with protein function, i.e. Tat
transactivation activity is reduced and RNA export
mediated by Rev is impaired. We have now further
studied PRMT6 function in the HIV-1 life cycle: 1)
involvement in establishing latency, 2) role as part of
an antiviral host defense, and/or 3) participation in
fine-tuning and optimization of localization patterns
and functions of Tat and Rev.
Conclusions: Intracellular PRMT6 levels primarily
fine-tune the HIV-1 life cycle by subtly altering the
localization patterns of Tat and Rev. This may slow
down the switch from the early to the late phase of
the viral life cycle in order to enhance overall viral
replication.
Abstract 16
Methods: Latency induction: We assessed RT activity
in the supernatant of U1 cells treated with different
drugs (NVP, PMA, Arginine Methyltransferase
Inhibitors AMI1/AMI3.4) after 48 and 96 h. PRMT6
levels in PBMCs: Purified peripheral blood mononuclear
cells (PBMCs) from individual donors were lysed with
RIPA buffer. Cell lysates were analyzed for PRMT6
by western blotting and either normalized to total
protein amounts or β-actin. Localization of Tat and
Rev: HeLa cells were transfected with Tat (wt)/Tat
(mut) or Rev (wt)/Rev (mut) and/or PRMT6 (wt
or mut) or siRNA against PRMT6. Fixed cells were
analyzed by confocal microscopy (Tat and Rev with
fluorescent tag, PRMT6 with antibody).
Results: U1 cells were readily inducible with PMA,
which produced 10- to 40-fold increases in RT activity
in the supernatants. In contrast, neither of the two
PRMT6 inhibitors were able to significantly increase
RT activity. Therefore, PRMT6 may not be fully
involved in establishing latency. Intrinsic levels of
PRMT6 in PBMCs were very low. Yet, PRMT6 may
be able to play an important role in antiviral cellular
host defense. Localization experiments showed an
altered pattern of Tat and Rev when PRMT6 was
cotransfected. While Tat alone mainly localized in the
nucleoli, Tat was more evenly distributed within the
nucleoplasm when PRMT6 was present. This was also
true for mutated Tat that cannot be methylated. Rev,
located in the nucleoli, was entirely relocalized to the
cytoplasm in the presence of PRMT6, as also occurred
with mutated non methylatable Rev. Furthermore,
total amounts of Rev seemed reduced in the presence
of PRMT6.
18
Combination Therapy for Treating
HIV Latency
TP Castor1, MA Munoz2, S Moreno2, E Munoz2
1 Aphios Corporation, Woburn, MA, USA; 2 University of
Cordoba, Cordoba, Spain
Background: HIV infects several cell types during
the course of infection and progression to acquired
immune deficiency syndrome (AIDS). The persistence
of latent HIV-infected cellular reservoirs represents
the major hurdle to virus eradication with highly
active anti-retroviral therapy (HAART). Reactivation
of the latent reservoirs could allow effective targeting
and possible eradication of the virus. Experiments
with relatively specific PKCs inhibitors suggest that
bryostatin-1, a potent PKC modulator, re-activates
HIV-1 latency thorough the PKC pathway. We thus
investigated biochemical targets downstream of
PKC.
Methods: Bryostatin 1 was extracted and purified
from Bugula neritina utilizing a supercritical fluid
with a polar co-solvent followed by downstream
chromatographic purification and crystallization.
Jurkat-LAT-GFP cells were stimulated with
increasing concentrations of bryostatin-1 and the
phosphorylation and degradation of the NF-κB
inhibitor IκBα. The phosphorylation (activation)
of the MAPKs, ERK and JNK, were investigated by
Western blot using specific mAbs. The percentage of
GFP+ cells was analyzed by flow cytometry in an EPIC
XL flow cytometer (Beckman-Coulter Inc. CA, USA).
Jurkat LAT-GFP cells were pretreated with inhibitors
for 30 min at the indicated dose and then stimulated
with bryostatin-1 (10 nM) for 6h.
Results: Bryostatin-1 induced phosphorylation
and degradation of IκBα, and also the activation of
the MAPKs, ERK1+2 and JNK1+2 in a concentration
dependent manner. Bryostatin-1 at the concentration
of 10 nM does not induce IκBα phosphorylation
and degradation and JNK activation but fully
reactivates HIV-1 latency. Therefore, therapeutic
activity of bryostatin-1 for HIV-1 latency can be
achieved at concentrations that do not activate signal
transduction pathways (i.e. NF-κB and AP-1) that
may result in negative side effects.
Abstract 17
In addition to its HIV-1-latency antagonizing
activity, bryostatin-1 also down-regulates, at 10 nM
concentration, the expression of the human HIV-1
receptors CD4 and CXCR4 and prevents de novo HIV1 infection as measured by virus-induced cytotoxicity
assays (EC50 of 26 nM).
1 ImQuest Biosciences, Frederick, MD, USA; 2 Arisyn
Therapeutics, Frederick, MD, USA
Bryostatin-1 also synergizes with Histone
Deacetylases (HDAC) inhibitors (valproic acid and
TSA) to antagonise HIV-1 latency. HDAC inhibitors
alone do not significantly reactivate HIV-1 latency
but reduces the concentration of bryostatin-1 (at
least one order of magnitude). Bryostatin-1 at 1 nM
concentration can induce HIV-1 reactivation in the
presence of therapeutically relevant concentrations
of valproic acid. Thus, the therapeutic activity of
bryostatin-1 can be drastically improved in humans by
utilizing a HDAC inhibitor in combination therapy.
Conclusions: Bryostatin-1 and their derivatives
with HDAC inhibitors can be used for the treatment
of HIV-1 latency. Combination therapy for the
treatment of HIV-1 latency can employ bryostatin-1
(and derivatives) and one of the following HDAC
inhibitors; valproic acid, butyrate derivatives,
hydroxamic acids and benzamides. While HDACs can
be used in continuous dosing protocol, bryostatins
can be used following a cyclical dosing protocol.
Inhibition of Late Stage Events
in HIV-1 Replication: Discovery
and Development of Therapeutic
Compounds with Effects on Viral
RNA Synthesis Which Potentially
Target Rev Function
TL Hartman1 and RW Buckheit, Jr.1,2
Although the effective use of highly active antiretroviral therapy results in the suppression of virus
production in infected individuals, it does not eliminate
low level virus production in cells harboring virus in
sanctuary sites or result in the elimination of infection.
Thus, the continued search for new antiretroviral
agents with unique and different mechanisms of
HIV inhibition remains critical, and compounds that
can reduce the level of virus production from cells
already infected with HIV, as opposed to preventing
de novo infection, would be of great benefit. We have
discovered and evaluated a series of compounds that
suppress HIV replication in cells which are chronically
infected with and constitutively produce HIV. ATI0917 (formerly FB636 from The Proctor & Gamble
Company) prevents virus replication by inhibiting the
production of viral messenger RNA in HIV-1 infected
cells. Mechanistic data suggests that the compound
acts as a transcriptional inhibitor with a biochemical
phenotype suggesting inhibition of Rev function
in the infected cell. The compound may interfere
with a cellular protein required for RNA synthesis
but the antiviral effects of ATI-0917 can be clearly
distinguished from any toxic effects on the target
cells. ATI-0917 yields a reduction in the quantity of
singly spliced and unspliced HIV RNA transcripts and
a corresponding increase in the quantity of multiply
spliced RNA species, resulting in a reduction in the
production of virus proteins and progeny virus. ATI0917 interacted in an additive fashion with all other
tested anti-HIV agents in both acute and chronic
19
in vitro antiviral assays. Resistant virus could not be
selected even after three years of passage of virus in
the presence of the compounds. Safety pharmacology
and toxicology studies have been performed with
ATI-0917 based on its original use as a systemic antifungal agent and these studies have demonstrated its
safety for use in humans. ATI-0917 has been initially
evaluated in a Phase 1 human clinical trial and shown
to be safe. Based on the results obtained, additional
formulation studies are in progress to improve the
pharmacokinetic profile of ATI-0917 to allow once
per day oral dosing. ATI-0917 is one of a series of
molecules that have been discovered which target
HIV transcription and which represent a novel new
treatment strategy as an addition to existing HAART
therapies and for the treatment of highly drug
resistant viruses as a salvage therapy.
Results: 42 patients had HIV/AIDS upon arrival,
14 were excluded secondary to lack of followup and
information about CD4 counts; 73% were female,
58% were black, mean age was 40.5, mean initial CD4
count upon arrival was 483.7 and 54% of the people
were started on ARTs initially. 75% of the patients
with initial CD4 counts less than 200 were started
on antiretroviral therapy versus 50% of those with
CD4 counts greater than 200 who were started on
antiretroviral therapy. Of the 14 patients who were
initially started on ARTs, 71% had an increase their
CD4 counts at 3 months and 64% had an increase at
6 months. Although there was an increase at both
intervals there was not a greater increase at 6 months
than 3 months. This could be a factor of compliance
as well as stress due to environmental changes.
Conclusion: Our study shows CD4 cell counts are
increased with the use of ART.
Abstract 18
HIV Infected Refugees: ART
Therapy and Its Affect on CD4
Counts at 3 and 6 Months
M Patil1, A Oladele2, and S Cookson1
1 Emory University School of Medicine, GA, USA;
2 DeKalb County Refugee Clinic, GA, USA
Objective: To determine if CD4 cell counts are
affected by travel and antiretroviral therapy (ART) in
HIV infected refugees.
Methods: This study was a retrospective chart
review conducted at a HIV refugee clinic from
January 2004 to December 2005. Patient factors
recorded included: age, sex, race, country of origin,
date of arrival, initial CD4 counts and those at 3 and
6 months and the initiation of ART. The patients were
also placed into categories based on whether or not
their CD4 counts were greater or less than 200. The
initiation of ART was compared to the initial CD4
counts and those at 3 and 6 month visits. Variable
were compared by T-test and chi-square analysis.
20
Prevention and
Drug Resistance
21
Abstract 19
Milestones in HIV Drug
Resistance: From In Vitro to
In Silico
B Larder
HIV Resistance Response Database Initiative (RDI),
Cambridge, UK
This presentation will review over 20 years of HIV
drug resistance research. Genetic characterisation
of herpes simplex virus DNA polymerase genes
with drug resistance mutations initially stimulated
early exploration of HIV-1 reverse transcriptase
(RT) functional domains. These in vitro site-directed
mutagenesis studies, reported in 1987, highlighted
potential RT residues that might mutate to confer
drug resistance. Seminal studies in 1988 with HIV
isolates from AZT-treated individuals led to the
finding that AZT resistance developed progressively
to high levels during monotherapy. Subsequently, a
specific group of four RT mutations was identified as
the genetic basis of this resistance. Further studies
revealed that at least two additional RT mutations
could combine with this group to confer varying
degrees of AZT resistance. Resistance to other drugs
was later discovered and characterised. In 1991, the
surprise observation was reported that as a patient’s
virus became resistant to ddI, pre-existing phenotypic
AZT-resistance actually reversed. This was also the
case for NNRTI-resistance conferred by RT mutation
Y181C. By 1995, it was shown that when combined,
AZT and 3TC significantly suppressed viral load
even though the M184V signature 3TC-resistance
mutation developed. An attractive explanation for
the observed sustained response was that the M184V
mutation suppressed the development of AZT
resistance. In parallel to the mechanistic studies of
drug resistance, new diagnostic tests and assays were
being developed. Specific resistance mutations could
be pinpointed using allele-specific PCR or automated
DNA sequencing. The drug susceptibility phenotype
could also be determined with accuracy using a new
standardised recombinant assay. Scale-up of these
assays led to a rapid expansion of individualised
drug resistance testing and the accumulation of
large amounts of phenotype data linked to genotype.
This culminated in the development of the ‘virtual
phenotype’ in 2000. This was a new tool to predict
phenotype from genotype by matching mutation
patterns and deriving an average phenotype from
the matched group.
Computational modelling
techniques, such as Artificial Neural Networks, were
subsequently employed to refine the quantitative
prediction of drug susceptibility from genotype. The
HIV Resistance Response Database Initiative (RDI)
was formed in 2003. This is a not-for-profit initiative
that has collated large amounts of HIV patient clinical
data and used computational modelling techniques
to predict a patients’ quantitative response to drug
combinations relative to viral resistance status.
Results of a small prospective clinical pilot study,
based on use of the latest models, will be presented.
Abstract 20
STOP HIV/AIDS: Seek and
Treat for Optimal Prevention of
HIV/AIDS
J Montaner
British Columbia Centre for Excellence in HIV/AIDS (BCCfE), Vancouver, Canada and International AIDS Society
Since 1996, widespread availability of HAART
has dramatically decreased rates of AIDS-related
morbidity and mortality among those engaged in
care. The overall success of HAART, however, has been
limited because of uneven access to therapy among
various groups of HIV infected individuals and across
geographical areas of the world. In British Columbia
(BC), Canada, despite a universal health care system
(which includes free provision of antiretrovirals)
HAART coverage remains suboptimal, particularly
among young men who have sex with men (MSM),
Aboriginal individuals, the homeless, the poor, the
mentally ill, and injection drug users (IDUs). As a
23
result, marginalized and hard-to-reach individuals
continue to bear a disproportionate burden of
HIV/AIDS related morbidity and mortality in the
province.
Over the last decade, increasing evidence has
become available indicating that HAART can impact
transmission of HIV (Montaner et al, Lancet,
2006;368:531-36). In brief, HAART rapidly and
effectively renders HIV-1-RNA undetectable in blood
and genital secretions and this is associated with
decreased risk of transmission. We recently developed
a mathematical model to predict the potential impact
of expanding HAART coverage among those in
medical need on the spread of HIV in BC (Lima et al,
JID, July 1, 2008;198:59-67). The model used data
on the natural history of HIV infection, risk factors,
HIV-1-RNA and CD4 cell counts, and the sources of
transmission to derive the probable incidence of HIV
in the coming years. Based on the available BC data,
the model indicates that the status quo (ie: initiation of
HAART at CD4 counts of 200 cells/mm3 or less, with
coverage levels of 50% among those in medical need,
and current compliance levels of 79%) will result in a
continued increase in new HIV infections somewhere
between 400 and 600 per year. In contrast, the model
predicts that an increase in HAART coverage to 75%,
90% and 100% among those in medical need would
result in a decline in the annual new HIV cases in the
range of 40%, 50% and 60%, respectively, resulting in
very significant savings over the long term.
Therefore, the BC-CfE proposes to expand HAART
coverage in BC specifically among hard-to-reach HIV
infected individuals. This program labelled “Seek
and Treat for Optimal Prevention of HIV & AIDS”
(STOP HIV & AIDS), will aim to further decrease
AIDS-related morbidity and mortality among those
already infected with HIV and to decrease new HIV
infections.
24
Abstract 21
Transmission of Drug Resistant
HIV: Patterns of Resistance to
New Antiretroviral Agents and
their Clinical Relevance
CAB Boucher
Department of Virology, Erasmus Medical Centre,
Erasmus University Rotterdam and Department of
Medical Microbiology, University Medical Centre Utrecht,
the Netherlands
Transmission of drug resistant HIV has been reported
from all parts of the world. Most available data come
from countries or region based surveillance studies
and convenient sample testing. The variation in
sampling strategies, technologies and definitions
limits the possibility to perform meta-analysis to
investigate the factors influencing transmission.
Nevertheless, the incidence of transmission of drug
resistant HIV ranges in areas where treatment is in
place between 5-15%. The patterns of resistance vary
from single mutations in one target gene to multiple
mutations in two target genes (protease and RT).
Initially it was believed that transmitted drug resistant variants (TDR) would revert over time to a fully
sensitive wild type virus. This because frequently the
replication capacity of drug resistant virus is reduced
as compared to wild type virus. We have shown that
frequently TDR can persist for years in the absence of
therapy even when their replication capacity is lower
than wild type. This is explained by compensatory
fixation e.g. the virus cannot evolute to wild type
viruses. Loosing compensatory mutations would
drive the virus in fitness valleys, which represent
dead end streets.
No systemic prospective studies looking into
the clinical relevance of TDR variants have been
performed. However a couple of retrospective studies
indicate that TDR mutations can affect outcome
adversely. In this respect the drugs most sensitive to
TDR are the one with a low genetic barrier specifically
the NNRTI class. Most regions with significant TDR
now have base line screening introduced. Baseline
resistant testing is most often done by population
sequencing, which can miss minority population of
TDR variants. In some retrospective studies minority
populations resistant to NNRTI were shown to be
clinically relevant. The implications of these findings
for clinical practice remain to be determined.
Abstract 22
Ninety-nine Is Not Enough:
Kinetic, Structural and
Thermodynamic Characterization
of HIV Protease with Insertion in
the Flap Region Isolated from an
HIV-positive Patient
M Kožíšek1,2, K Šašková1,2, P Řezáčová3, J Brynda3,
NM van Maarseveen4, M Nijhuis4, and J Konvalinka1,2
1 Institute of Organic Chemistry and Biochemistry,
Academy of Sciences of the Czech Republic, Prague,
Czech Republic; 2 Department of Biochemistry, School of
Science, Charles University, Prague, Czech Republic;
3 Institute of Molecular Genetics, Academy of Sciences of
the Czech Republic, Prague, Czech Republic; 4 EijkmanWinkler Institute, Department of Virology, University
Medical Center, Utrecht, the Netherlands
Background: HIV protease represents a prime
target for rational drug design, and protease
inhibitors are powerful antiviral drugs that
significantly decrease patient mortality. However,
they exert a powerful selection pressure on the
virus, which results in appearance of viral strains less
sensitive to the inhibitors. Resistance to virostatics
is regarded a major obstacle in the treatment of HIV
positive patients. In addition to resistant mutations,
insertions in the genes encoding reverse transcriptase
and protease were described. It is well known that the
inserts in RT play an important role in development
of drug resistance; their function in PR has been
described recently (Kožíšek et al., J. Virol. 2008).
Results: We identified an amino acid insertion
at position 35 of HIV PR isolated from a patient
treated by protease inhibitors for a prolonged
period of time, and we set out to characterize the
contribution of this insertion to viral resistance on
the molecular level. Resistant PR variants with or
without the insertion at position 35 were cloned in
E.coli, purified and enzymologically characterized
using a chromogenic peptide substrate and a panel of
inhibitors. We found that the E35EE insertion does
not significantly decrease the catalytic activity of the
enzyme but brings about an approximately tenfold
increase in the relative inhibition constant for some
protease inhibitors. X-ray structures of the resistant
PR-inhibitor complexes were determined to 1.8 Å
resolution with very good structural factors. Thermal
analysis by differential scanning calorimetry (DSC)
was applied to determine the thermal stability of
proteases with and without insertion. Stabilization
effect of insertion on structure was comparable to
active site mutations.
Conclusion: We conclude that amino acid
insertions into the PR sequence in the vicinity of
the binding cleft represent novel mechanism of HIV
resistance development.
Abstract 23
TOPO Cloning and
Pyrosequencing Revealed a
Novel S68 Deletion in HIV-1
Reverse Transcriptase Selected
by Dexelvucitabine in Human
Lymphocytes
I Massud, M Ruckstuhl, K Rapp, M Detorio, and
RF Schinazi
Center for AIDS Research, Emory University School of
Medicine/VA Med Center, Atlanta, GA, USA
Introduction: Antiviral resistance is a major
threat to successful anti-HIV treatment and the
presence of low frequency mutations can facilitate
viral escape. Resistance to multiple nucleoside RT
25
inhibitors (NRTI) has been associated with an amino
acid substitution at the nucleoside binding site of the
enzyme and with the insertions or deletions in the β3β4 hairpin loop in the finger subdomain of the HIV-1
RT. Our research has identified a novel deletion of the
S68 codon in HIV-1 RT that reduces the effectiveness
β-D-2’,3’-dideoxy-2’,3’-didehydro-5-fluorocytidine
(Dexelvucitabine, DFC) and other NRTI in infected
human PBM cells.
Methods: Primary human PBM cells were treated
with DFC at 0.1 µM for one hr prior to inoculation
with HIV-1LAI (WT). Virus was passaged every 6 days
with a fresh treatment of DFC, ranging from 0.1 µM to
6 µM over 52 weeks. RT activity was measured weekly
and used to determine percent inhibition by DFC.
HIV-1 from PBM cells supernatants was amplified
and cloned using TOPO cloning (Invitrogen, Carlsbad,
CA). Sequencing of HIV-1 RT amino acids 1-300 was
performed in parallel between the control virus and
DFC treated virus to uncover mutations selected
from the applied drug pressure. Amplicons generated
were pyrosequenced by Research and Testing
Laboratory (RTL, Lubbock, TX) using the Roche
FLX pyrosequencer (Roche Diagnostic Corporation,
Indianapolis, IN). Pyrosequencing was performed
using standard amplicon protocols as suggested by
manufactures instruction. Each library was sequenced
in both the forward and reverse direction.
Results: In vitro testing of HIV-1 infected primary
human lymphocytes (PBM cells) treated with DFC
selected for a novel deletion of AGT at codon 68 (S68∆).
Utilizing TOPO cloning, the S68∆ and K65R appeared
at week 14 as 70 % and 10% of the total population,
respectively and they continued to be present until
week 52 were they appeared as a mixture with K65R
(63%). Four of these samples were sequenced using
the Roche FLX system. Pyrosequencing identified
the S68∆ and 15 extra mutations of potential clinical
significance with an occurrence higher that 1% and
lower than 9%. At week 14, the frequency of S68∆
and K65R was 0.85% and 0.01%, respectively. By
week 52, the frequency had increased to 22.3%
and 24% respectively. For scoring drug resistance
mutations, the HIV Drug Resistance Database at
26
Stanford University was used. The S68∆ selected virus
was phenotyped against various NRTI and NNRTI
to obtain a resistance profile by drug susceptibility
and an enzymatic assay. Drug susceptibility results
suggest that virus with the S68∆ displayed greater
than 30-fold increase resistance to DFC, 3TC,
(-)-FTC, TDF, ABC, and DAPD, but remained
susceptible to ZDV, ddI, ddC, d4T, D-FDOC, or DOT.
Conclusion: These studies revealed the significance
of a novel deletion in the HIV-1 hairpin loop and
demonstrated the feasibility of using pyrosequencing
for efficient genotyping. The novel S68∆ may prove
to be an important variable to be considered in NRTI
multi-drug resistance (MDR) treatment strategies.
Abstract 24
Operation Sweet Tooth:
Effective Use of Social Marketing
Campaigns in Non-Traditional
Social Settings
T McPhaul
National AIDS Education & Services for Minorities, Inc.,
Atlanta, GA, USA
OBJECTIVE: Operation “Sweet Tooth” is a social
marketing campaign designed to capture the
attention of African American MSMs. The campaign
is designed to draw attention to some of the potential
HIV/STD exposure risks associated with oral sex. The
organization’s goal for this campaign is to distribute
10,000 condoms during the Black Gay Pride Labor
Day Weekend, and to have quality education sessions
regarding oral sex risks with at least 1000 eventgoers.
METHODS: The subtheme for 2008 was “Team
Survival” Your Mission: To Stay Safe. Staff and
volunteers wore T-Shirts bearing the “Team Survival”
slogan; also they wore hats, khaki shorts, boots, a
canteen and dog tags. Candy is associated with candy
flavored condoms (i.e. cherry candy with cherry
flavored condoms). Individuals are encouraged
not to brush teeth just prior to performing oral
sex, but instead to use mints, gum and candy as an
alternative. Safer sex kits were packaged in 2.5” X 4.5”
manila envelopes. There was a label on the exterior
of the package displaying “Your Mission: To Stay
Safe”. Condom kits contained condoms, lubrication,
and a piece of candy. Social marketing campaigns
can appear less threatening while adding clarity;
often they provide brevity and sometimes levity. The
advertisements are catchy even to non-gay identified
men; this can lead to a diffusion of “guilt.”
RESULTS: NAESM provided education in 1500
encounters in 2007. Even with the outreach efforts
being lead by a different core group in 2008, more
than 1000 education encounters was achieved. The
message was visible at all of the larger and more
popular gatherings from educational to merely social.
Individuals were seeking out condoms and information
on their own rather than being aggressively pursued;
a likely result of more effective education.
CONCLUSIONS: A significant amount of “health
education” was provided during this opportunity. It
was a chance to do more than just hand out condoms,
which alone would have still proven beneficial. In total
NAESM distributed over 10,000 condoms in 2007
and 9,000 condoms in 2008. The “Operation Sweet
Tooth” images help reflect that healthier behavior
is the “in” thing. This particular campaign is one
whereby immediate and consistent positive feedback
was provided from event-goers. A large number of
those who came in direct contact with the images in
“Operation Sweet Tooth” advertisements expressed
that they enjoyed the images and the accompanying
information which often prompted more STD/HIV
related questions by guests. The questions even
extended to medical care requests and social services
inquiries beyond those provided by the NAESM.
However, the staff was knowledgeable about the full
range of resources available.
Abstract 25
Utilizing Mental Health
Counseling in African American
Men who have Sex with Men
Minority Populations as a Primary
and Secondary HIV Prevention
Tool
T McPhaul
National AIDS Education & Services for Minorities
(NAESM), Atlanta, GA, USA
OBJECTIVE: Persons receive an HIV positive
diagnosis, and often do not have adequate tools for
processing this information in a healthy manner.
Counseling can be extremely helpful as an HIV
Prevention tool from the framework that often people
engage in either risky or self-destructive behaviors due
to a variety of other factors such as depression , low
self-esteem, as well as a lifetime of neglect, deprivation
and abuse. As a secondary prevention tool mental
health counseling will address underlying causes for
self-destructive behavior in HIV+ individuals and
lead to less risk taking, and healthy disclosure. The
U.S. Surgeon General has reported that overall only
one-third of Americans with a mental illness or a
mental health problem get care. Yet, the percentage
of African Americans receiving needed care is only
half that of non-Hispanic whites.
METHODS: In this model counseling services will
be provided by a Licensed Professional Counselor,
or Licensed Clinical Social Worker. In addition to
collaborations with various agencies providing
services to at-risk populations, social marketing
campaigns aimed at venues frequented by at risk
populations will be employed; resulting in HIV+, and
high risk HIV- individuals accessing mental health
services. Individuals accepted into care will have a
plan developed with a counselor, which will include
a course of counseling ranging from 3 months to one
year.
27
RESULTS: Limited data is available at this time
because this program has been recently funded.
Individuals clearly falling within critical values will
then go on for an intake and assessment where
depth and complexity of issues are examined. At
the conclusion of the counseling term, an additional
assessment will be provided to evaluate counseling
effectiveness. Data will be analyzed and scored to
chart success of the counseling term.
CONCLUSIONS: African American Men who have
Sex with Men, those hardest hit by the HIV/AIDS
epidemic, have complex psychological underpinnings
that are often augmented by racism, homophobia,
familial and societal rejection, physical and emotional
abuse, self-loathing and a struggle for identity.
Culturally competent mental health counseling can
help to prevent HIV transmission, and contribute to
improved quality of life for HIV positive individuals.
There exists research identifying that African
Americans from various walks of life do not seek
mental health treatment as often as is warranted,
or as regular as their Caucasian counterparts. There
may be no one cause defined for this phenomenon,
however, historically African Americans and other
people of color have had similar resistance and/or
obstacles to receiving care for physical health as well.
Studies show that counseling for African Americans
can be effective when accessed in a timely pattern.
Knowing at the outset certain factors that have
influenced an individual’s mental health foundation,
such as level of stability of the family structure that
a person experienced as a child, can yield valuable
insight into behavior patterns that if known by those
providing HIV prevention services could yield quite
different results. Thus, it is critical that the necessity
for good mental health be realized and utilized as a tool
to aid in both primary and secondary HIV prevention.
Fully embracing this idea may be the most formidable
approach to the eradication of HIV/AIDS.
28
Abstract 26
Sex is Good: An Investigation into
the Quality of Life and Sexual
Practices Among Individuals on
HAART in British Columbia
A Mtambo1, EK Brandson2, A Kaida2,4, KA Fernandes2,
T Orchard2, JSG Montaner2,3, and RS Hogg1,2
1 Faculty of Health Sciences, Simon Fraser University,
BC, Canada; 2 BC Center for Excellence in HIV/AIDS, BC,
Canada; 3 Department of Medicine, University of British
Columbia, BC, Canada; 4 School of Population and Public
Health, University of British Columbia, BC, Canada
Objective: We measured the prevalence of sexual
activity among a cohort of HIV+ individuals on
HAART to identify quality of life measures and
socio-demographic predictors by gender and sexual
orientation.
Methods: Individuals enrolled in the longitudinal
investigations into support and ancillary health
services (LISA) cohort (N=457) answered questions
about oral, anal or vaginal sexual intercourse and
the HIV-targeted quality of life. Fifty five percent
of participants (70% of gay and bisexual, 47%
of heterosexual males and 49% of heterosexual
women) indicated that they were sexually active in
the six months prior to participating in the survey.
Multivariate models were used to measure the
associations.
Results: The study found that individuals who
were sexually active performed better on most of the
quality of life measures than those who abstained.
Consistent with other research, multivariate analyses
for the whole cohort showed that being sexually
active was associated with being in a relationship
(OR: 0.26 (CI: 0.15,0.43)), having better body image
(OR: 0.82 (CI: 0.70,0.95)), and higher scores on
sexual function(OR: 1.39 (CI: 1.22, 1.58)). Among
gay and bisexual men, being sexually active was also
associated with higher life satisfaction (OR: 1.36 (CI:
1.02, 1.82)). In heterosexual females, being sexually
active was associated with being depressed and having
less disclosure worries (OR: 1.28 (CI: 1.02, 1.61)).
Conclusion: We need to further engage with
people on HAART, their service providers, and other
relevant community organizations to ensure that
“sex” is on the agenda, supported in ways that are
healthy and appropriate to these different groups
and creatively incorporated into long-term HIV
management programs and strategies in order to
maximize function and wellbeing in individuals living
with HIV.
Abstract 27
Vertical Transmission of HIV
Infection in Western Romania
M Sandu, M Pop, R Costa, C Laudacescu, J John, and
M Şerban
“Louis Turcanu” Children’s Emergency Hospital, IIIrd
Pediatrics Clinic, Timişoara, Romania
Background: During the years 1995-1998
Romania became infamous making a sad European
record - that of having the most number of HIV/AIDS
children with horizontal transmission. Since the
epidemic was discovered (1990), the number of cases
with vertical transmission at the national level was
5%. During the course of time, the little girls infected
with HIV in the late 80’s have become adolescents
now and a part of them mothers to babies.
Materials and methods: A retrospective
analysis of vertical transmission of HIV infection in
the western region of Romania. A total of 720 cases
of HIV infection admitted during the period 19902007. Out of this lot, 41 cases (5.7%) transmitted
from seropositive mothers. These cases have been
analyzed based on their evolution, with or without
HAART, clinically and immunologically.
Results: Of the 41 children born to seropositive
mothers, 6 are uninfected (14.63%). 23 cases were
diagnosed until the year 2000, while the mothers
have been diagnosed after the child’s diagnosis.
Only 5 mothers (since 2000) did the prophylaxis for
vertical transmission. 6 mothers were infected during
88-90 while 3 (also born in 89) were diagnosed
during their pregnancy. After 2000, 5 mothers were
diagnosed post-child delivery. 41.2% of children
infected through vertical transmission have died.
HAART was introduced in 28 cases (starting since
1996). Currently, 7 patients are in Stage B, 9 in Stage
C and 2 in Stage EB.
Conclusions: 1. Low frequency of vertically
transmitted HIV infection, 2. High mortality rate.
Death occurred in smaller aged children and they
did not benefit the HAART, 3. As the patients of the
1989-90 generations were known to be pregnant,
prophylactic measures were initiated, while since
2000 majority of the newborns received prophylactic
ARV’s (and were not breastfed).
Abstract 28
Development of the Dual Acting
Pyrimidinedione IQP-0528
as a Vaginal Topical Anti-HIV
Microbicide
KM Watson, L Yang, CE Buckheit, and RW Buckheit, Jr.
ImQuest BioSciences, Inc., Frederick, MD, USA
IQP-0528 is a highly potent dual-acting HIV inhibitor
targeting both reverse transcription and virus entry.
The compound is non-toxic to all tested cell lines in
vitro, including primary human cells, and the normal
vaginal flora Lactobacillus. In standard assays, IQP0528 was active against all clinical strains of virus in
the nanomolar to sub-nanomolar concentration range
in PBMCs, dendritic cells and monocytes macrophages
with therapeutic indices greater than one million.
Equivalent or greater activity was observed when
IQP-0528 was evaluated in the presence of additives
such as mucopolysaccharides or simulated vaginal
29
and seminal fluids. The activity of the compound
was not affected in cell-based entry assays mimicking
the transition from low to neutral pH that occurs
at the time of ejaculation. IQP-0528 inhibited both
cell-free and cell-associated virus transmission to
CD4 expressing cells in virus transmission inhibition
assays and was highly active in the microbicide
transmission and sterilization assay (MTSA). IQP0528 was not active against several viral, bacterial or
fungal STI-causing organisms. In pre-formulation
studies using standard methodology, IQP-0528 was
soluble in a variety of solvents and was stable at
ambient temperature and at pH’s less than 8. Acute
toxicology evaluations determined the compound
to be non-toxic up to 1000 mg/kg/day when dosed
intravenously. Genotoxicology evaluations were all
negative. IQP-0528 is a novel candidate for a vaginal
topical microbicide based on its dual mechanism
of action, high level of potency, lack of toxicity,
compatible formulation profile and toxicology profile.
As a microbicide, IQP-0528 would potentially inhibit
two steps in virus replication which occur prior to
reverse transcription and could be effectively used in
combination with other microbicide products. IQP0528 is currently being formulated in a gel and an
intravaginal ring for delivery of the compound.
both entry inhibitors in the central nervous system
and potential development of resistance. We report
low level penetration of both entry inhibitors and
selection of enfuvirtide resistance in cerebrospinal
fluid (CSF) of a patient with suppressed plasma HIVRNA levels.
Abstract 29
Although adequate serum concentrations of
enfuvirtide (3,74 µg/ml) could be detected in the
plasma, only marginal enfuvirtide concentrations
were observed in CSF (0,055 µg/ml). Furthermore,
the maraviroc level in plasma was 0,146 µg/ml, while
only traces below the limit of quantification were
detected in CSF.
Development of Resistance to
Enfuvirtide in Cerebrospinal
Fluid in a Patient with Suppressed
Plasma HIV-1 RNA
SFL van Lelyveld1, M Nijhuis1, I Wilting1, F Baatz2,
M Kurowski3, WM van den Bergh1, D de Jong1,
IM Hoepelman1, and AMJ Wensing1
1 University Medical Center Utrecht, Utrecht, the
Netherlands; 2 Retrovirology Laboratory, Luxembourg,
Luxembourg; 3 Therapia GmbH, Berlin, Germany
Background: Currently, enfuvirtide and maraviroc
are available for infections with multi-drug resistant
HIV-1. Limited data are available on penetration of
30
Methods: Longitudinal plasma and CSF samples
were analyzed. Population genotypic resistance
analysis was performed (protease, RT and env). CSF
and plasma drug levels were measured by liquid
chromatography tandem mass spectrometry.
Results: Salvage therapy with maraviroc,
enfuvirtide, combivir and tenofovir was initiated
in a 50 year old male with a long treatment history.
After an initial slow decay, plasma HIV-RNA was
suppressed below the limit of detection for 8 months.
Then, lumbar punctions were performed because of
neurological complaints. While plasma viremia was
still suppressed, HIV RNA levels in CSF appeared to
be 2780 and 1490 copies/ml. Subsequent addition of
darunavir/r resulted in suppression of CSF HIV-RNA
levels. Subacute combined degeneration of the spinal
cord due to vitamin B12 deficiency was identified
as the most probable cause of his symptoms and
suppletion was started.
Genotypic analysis of the virus population in CSF
showed no changes in the viral protease and RT
sequences compared to viral populations detected
in plasma before initiation of salvage therapy. Also
sequence analysis of the gp120 V3-loop of the
CSF sample showed no differences compared with
baseline, suggesting that no change in HIV-1 tropism
had occurred. Interestingly, analysis of gp41 revealed
the enfuvirtide-associated V38A mutation in CSF.
Conclusions: We observed detectable HIV-RNA
levels in CSF in absence of plasma viremia. Addition
of a boosted protease inhibitor suppressed HIVRNA levels in CSF, suggesting that the detected
virus originated from viral replication and not from
production of integrated virus only.
Low enfuvirtide concentrations might have enabled
low level viral replication in CSF and subsequent
selection
of
drug-resistance.
Alternatively,
enfuvirtide-resistant virus could have been selected
in the plasma population during the slow initial
viral decay after start of the salvage regimen. In this
scenario, replication of enfuvirtide-resistant virus
was effectively inhibited by the other components of
the antiviral regimen in the plasma but not in CSF.
This case study stresses the potential risk of selection
of resistant HIV-1 virus by low level penetration of
antiretroviral drugs into the central nervous system.
Further research on this topic is necessary to fully
understand the clinical implications.
31
HIV Therapy in
Developing Countries
33
Abstract 30
To Wean or Not to Wean:
Prevention of Mother-to-child
Transmission through Breast Milk
C van der Horst
In 2005, 360,000 infants were infected with HIV
through breastfeeding. Breastfeeding confers
nutritional,
immunologic,
developmental,
psychologic, social, and economic benefits including
overall lower infant morbidity and mortality,
particularly in the first six months of life. The greatest
benefits accrue to exclusively breastfed infants, who
are less likely to become infected with HIV than
infants who receive both breast milk and other liquids
or solid. Breastfeeding also provides benefits to the
mother including a delay in resumption of ovulation,
resulting in increased child spacing. In addition
to individual health benefits, there are economic
and social benefits due to savings from formula
purchases.
Due to scarce or unsafe breast milk substitutes,
the issue of HIV transmission to the infant via
breastfeeding is unique to resource-poor countries.
While formula feeding does decrease the risk of HIV
transmission to the infant and may be associated with
decreased maternal mortality, it is also associated with
a higher number of early deaths among HIV-negative
infants due to diarrheal disease and pneumonia
although there is recent conflicting data on the latter.
In those countries where breastfeeding is the norm,
use of formula marks women as being HIV-positive.
weight loss may place HIV-infected mothers at greater
risk of succumbing to opportunistic infections,
indirectly increasing their disease progression and
risk of death.
HIV-infected women in resource-limited settings are
faced with a tragic dilemma. Either they breastfeed
their infants with its associated risk of HIV
transmission, or they protect their children from
HIV by replacement feeding, which, while it may
also be nutritionally less demanding for themselves increases the infant’s risk of malnutrition and death
if replacement feeding is not affordable, feasible,
and safe. Recent studies have begun to provide
some possible solutions to this dilemma and will be
reviewed.
References:
1. Kilewo C, et al., J Acquir Immune Defic Syndr. 2008
Jul 1;48(3):315-23.
2. Kuhn L, et al., N Engl J Med. 2008 Jul 10;359(2):
130-41.
3. Kumwenda NI, et al., N Engl J Med. 2008 Jul
10;359(2):119-29.
4. Leroy V, et al., PLoS ONE. 2008 Feb 20;3(2):e1645.
5. Six Week Extended-Dose Nevirapine (SWEN) Study
Team, et al., Lancet. 2008 Jul 26;372(9635):30013.
6.Thomas T, et al., 15th Conference on Retroviruses and
Opportunistic Infections 2008. Abstract 45aLB.
7. van der Horst CV, et al., Contemp Clin Trials. 2008
Sep 7.
Among breastfeeding populations, the transmission
rates from 6 weeks to 6 months in the various
non-formula arms ranged from 2.9% to 8.1%, and
from 5.3% to 12.4% over the 6-week to 12-month. Producing breast milk of adequate quantity and
quality is, however, nutritionally demanding for
mothers, particularly for those who have chronic
infections.. Maternal depletion leading to rapid
35
Abstract 31
Topical Microbicides: Moving
Towards Topical Pre-exposure
Prophylaxis (PrEP)
S Hillier
University of Pittsburgh School of Medicine, Department
of Obstetrics, Gynecology and Reproductive Sciences,
Pittsburgh, PA, USA
Sexual intercourse is the primary mode of HIV
transmission worldwide. Topical microbicides are new
products being developed for the prevention of the
sexual transmission of HIV, and are part of the HIV
prevention toolbox. First generation microbicides
were developed based on the premise that HIV could
be inactivated in the vaginal lumen by acidifying the
vagina (BufferGel), disrupting the viral membrane
(Savvy) or by interrupting the fusion of HIV with
host cells (Carraguard, PRO2000/5(P) and cellulose
sulfate). Products which have completed effectiveness
testing include cellulose sulfate, Carraguard and
Savvy, but none were found to be effective in reducing
the rate of male to female transmission of HIV. Two
other nonspecific microbicides, BufferGel and 0.5%
PRO2000/5 (P), are being evaluated for the prevention
of HIV in women in studies which will be completed
in 2008-9. Antiretroviral (ARV) agents having high
potency against HIV are now being evaluted as
topical microbicides. Tenofovir has been formulated
for vaginal application in a water-based gel and has
been evaluated for safety, pharmacokinetcs and
acceptability in phase 1 and 2 studies. The results of
these studies suggest that 1% tenofovir gel is safe
and acceptable for use by women at the time of coitus
or on a daily basis. Women who have applied 1%
tenofovir gel vaginally have higher levels of tenofovir
in the genital tissue compared to women using oral
tenofovir, with a fraction of the systemic levels as
compared with oral tenofovir. Thus, topically applied
tenofovir may provide higher drug levels at the site
of infection, with a lower risk of systemic toxicity,
than oral PrEP. A phase 2B study of 1% tenofovir
used before and after coitus for prevention of HIV
36
is underway (CAPRISA-004). A second study in
4200 women comparing oral tenofovir, Truvada, 1%
tenofovir gel and placebo controls (the VOICE trial) is
planned to start in 2009. This study will provide data
on the relative effectiveness of orally and vaginally
administered tenofovir for prevention of HIV. Nonnucleoside reverse transcriptase inhibitors, including
UC781, dapivirine (TMC 120) and MIV 150, are
also being developed for topical administration in
the form of drug impregnated rings (which would
be inserted into the vagina for 1-3 months), quickdissolve films, fast dissolving tablets and gels. A
number of entry inhibitors, CCR5 analogs and
combination approaches are currently in preclinical
development as microbicides. Because receptive anal
intercourse is common among both heterosexual
women and MSM, the safety of vaginal microbicide
products when applied rectally is being evaluated. In
addition, some novel product formulations are being
developed specifically for rectal application. The field
of microbicides has transitioned from the use of nonspecific agents to the topical application of ARV’s for
the prevention of HIV.
Abstract 32
Glycan Deletions in the HIV-1
gp120 V1/V2 Domain
Compromise Viral Infectivity,
Sensitize the Mutant Virus Strains
to Carbohydrate Binding Agents
and Represent a Specific Target for
Therapeutic Intervention
J Auwerx1, KO François1, K Covens2, K Van Laethem2,
and J Balzarini1
1 Laboratory of Virology and Chemotherapy, Rega
Institute for Medical Research, K.U. Leuven, B-3000
Leuven, Belgium; 2 Laboratory of Clinical Virology and
Epidemiology, Rega Institute for Medical Research, K.U.
Leuven, B-3000 Leuven, Belgium
Background: The glycoprotein gp120 of HIV1(IIIb) contains 24 utilised N-linked glycosylation sites
that contain oligosaccharides of the complex type,
hybrid type and high-mannose type. Carbohydratebinding agents (CBAs), such as the mannose-specific
Hippeastrum hybrid agglutinin (HHA) and the GlcNAcspecific Urtica dioica agglutinin (UDA), frequently
select for glycan deletions in all different domains
of HIV-1 gp120, except in the V1/V2 domain. To
reveal the underlying mechanisms, a broad variety
of 31 different virus strains containing one or several
N-glycan deletions in V1/V2 of the gp120 of the X4tropic HIV-1NL4.3 were constructed by chimeric virus
technology.
Materials and methods: The NXS/T
glycosylation recognition sites were converted into
a QXS/T amino acid sequence by Multi Site-directed
Mutagenesis (Stratagene). About 30 combinations
of glycan deletions in V1/V2 were successfully
introduced into pBlue-env (a plasmid containing the
env-sequence) and amplified by PCR. After applying
chimeric virus technology in 293T cells for this
PCR product with a molecular HIV-1/NL4.3 clone
containing the eGFP gene, we used the resulting
recombinant virus strains to infect U87.CD4+.CXCR4+.
CCR5+ cells and to prepare virus stocks. Afterwards,
these virus stocks were used in co-receptor tropism
determination, replication fitness and antiviral
assays using HHA, UDA and pradimicin A (PRM-A)
as CBAs.
Results: A broad variety of virus strains containing
one or several N-glycan deletions in V1/V2 of gp120
were obtained. The mutant virus strains analysed for
co-receptor usage consistently used CXCR4. A coreceptor switch to CCR5 or dual co-receptor tropism
was not observed.
With a few exceptions, the more glycans were deleted
in the gp120 V1/V2 domain, the more the replication
capacity of the mutant viruses became compromised.
As there was no difference between the mutant viruses
in CD4 binding efficiency and their sensitivity to the
inhibitory activity of soluble CD4 and the CXCR4
antagonist AMD3100, we concluded that the loss of
replication capacity was not due to major structural
envelope changes that would compromise CD4 or
CXCR4 binding.
None of the mutant virus strains showed a markedly
decreased sensitivity to the inhibitory activity of
HHA and UDA. Instead, an up to 2- to 10-fold higher
sensitivity to the inhibitory activity of these CBAs
was consistently observed.
Conclusions: Our data provide an explanation
why glycan deletions in the gp120 V1/V2 domain
rarely occur under CBA pressure and confirm the
important functional role of the glycans in the HIV-1
gp120 V1/V2 domain. The detailed data are reported
and discussed in J. Auwerx et al., Virology, in press
(2008).
Abstract 33
Gag NC/p1 Protease Resistance
Mutations can cause Selection
of Additional NC/p1 Changes to
Optimize Cleavage Efficiency and
Replicative Capacity
NM van Maarseveen1, PJ Schipper1, D de Jong1,
CAB Boucher1,2 and M Nijhuis1
1 Department of Medical Microbiology, University
Medical Centre Utrecht, Utrecht, the Netherlands;
2 Department of Virology, Erasmus Medical Centre,
Rotterdam, the Netherlands
BACKGROUND: Substrate based protease inhibitor
(PI) resistance due to mutations in NC/p1 is caused
by an enhanced processing of the gag protein. We
investigated the impact of enhanced gag processing
due to NC/p1 resistance mutations on replicative
capacity (RC) and the consequences for evolution in
absence of protease inhibitor pressure.
METHODS: A set of four recombinant viruses
containing NC/p1 mutations conferring different
levels of PI resistance were generated: HXB2431V,
HXB2437V, HXB2437T and HXB2436E+437T. To investigate
the effect of enhanced gag processing on RC, viral
replication curves were generated. To investigate
the potential evolutionary pathways in absence of
37
PI pressure, multiple individual in vitro evolution
experiments were performed, after which complete
Gag and protease were sequenced. From the viruses
that were selected RC, gag processing (quantitative
immunoblot analysis) and PI susceptibility (MTT
assay) were assessed.
RESULTS: Single NC/p1 mutants which displayed
only a slight increase in PI resistance didn’t show an
obvious change in RC compared to wild type. This was
also reflected in the in vitro evolution experiments
where the single NC/p1 mutants showed no signs
of evolution, with the exception of the selection of
A429K in 1/5 experiments for HXB2431V. In contrast,
the double NC/p1 mutant (HXB2436E+437T) which
displayed a clear increase in processing efficiency and
PI resistance, also demonstrated a clear reduction
in RC. Interestingly, in all evolution experiments,
amino acid changes in/near the NC/p1 site were
observed (2/5: -436E; 2/5: +435R; 1/5: +438R). These
selected changes restored the processing efficiency
and RC. Furthermore, it was observed that due to the
normalisation of gag processing efficiency, in parallel
PI susceptibility returned to wild type level.
CONCLUSIONS: The results from this study clearly
demonstrate that there is an optimum rate for HIV-1
gag cleavage. When enhanced gag processing due to PI
resistance mutations in NC/p1 reduces RC, HIV-1 can
modulate the NC/p1 sequence by selection additional
changes to restore gag cleavage and RC.
Abstract 34
Safety, Tolerability and Efficacy of
Darunavir/ritonavir in Treatmentexperienced Women with HIV
Infection: Interim Analysis
of GRACE (Gender, Race, And
Clinical Experience)
C Zorrilla1, J Currier2, K Squires3, D Averitt Bridge4,
R Ryan5, A Mazikewich6, and J Mrus6 on behalf of the
GRACE Study Group
1 University of Puerto Rico School of Medicine, San Juan,
PR, USA; 2 University of California, Los Angeles, School
of Medicine, Los Angeles, CA, USA; 3 Jefferson Medical
College of Thomas Jefferson University, Philadelphia, PA,
USA; 4 The Well Project, Inc., Atlanta, GA, USA; 5 Tibotec,
Inc, Yardley, PA, USA; 6Tibotec Therapeutics, Bridgewater,
NJ, USA
Background: GRACE, the largest trial to date of
antiretroviral treatment-experienced women in North
America, is a multi-center, open-label phase IIIb trial
designed to assess sex and race differences in efficacy,
safety, and tolerability of darunavir/ritonavir (DRV/r)
over 48 weeks. The study was designed to enroll a
predominantly female, racially diverse population,
with 65 GRACE study sites selected to meet this
objective. We report a pre-planned interim analysis
of the first 203 patients (of a total of 429 enrolled) to
complete Week 24 or discontinue sooner.
Methods: Adults with prior antiretroviral treatment experience and HIV-1 RNA ≥1000 copies/
mL were enrolled. All patients received DRV/r
600/100mg bid plus an investigator-selected
optimized background regimen (OBR). Select NRTIs
and etravirine were provided. This pre-planned
interim analysis was conducted to assess safety and
tolerability. We also present preliminary efficacy
results using ITT-TLOVR (intention-to-treat-timeto-loss-of-virologic-response) and TLOVR-non-VF
(non-virologic failure) censored algorithms; the latter
excludes patients who discontinued for reasons other
than virologic failure (VF).
38
Results: 180 women and 23 men were included
in the interim analysis; safety and efficacy are not
presented separately for men due to small sample
size. The mean age of women was 42 years (range
19-78). 65% of women were African American, and
22% were Hispanic/Latino. The mean baseline viral
load and median baseline CD4 count for women were
4.67 log10 copies/mL (SD 0.86) and 206 cells/mm3
(range 1-868), respectively. More than half (59.4%)
of women had prior treatment experience with ≥2
protease inhibitors at the time of study entry. Overall,
22.7% of patients (44 women and 2 men) discontinued
the study; 7.4% of patients (14 women and 1 man)
discontinued due to adverse events (AEs) and 0.5%
of patients (1 woman and no men) discontinued for
VF. Among all patients, the most common (≥2%)
grade 2-4 AEs at least possibly related to study drug
were nausea (5.9%), diarrhea (5.4%), rash (3.0%),
weight gain (3.0%), increased transaminases (2.0%),
dizziness (2.0%), and dyspepsia (2.0%). Serious AEs
(SAEs) were reported in 18.2% of patients, and the
most common SAE was pneumonia (3.9%). At 24
weeks, 50.6% (ITT-TLOVR) and 65.5% (TLOVR-nonVF censored) of women achieved HIV-1 RNA <50
copies/mL. The mean increase in CD4 count from
baseline [ITT-non-completer = failure] for women
was 86 cells/mm3.
Conclusions: The GRACE study is fully enrolled
(287 women, 142 men), demonstrating that women
from North America, including women of color, can be
successfully recruited to participate in clinical trials of
antiretrovirals in HIV infection. No unexpected AEs
were noted in this interim analysis. Approximately
one-quarter of women discontinued the study prior
to Week 24; reasons were generally unrelated to AEs
or VF. Response rates were within the expected range
from previous clinical trials of DRV/r in treatmentexperienced patients.
Abstract 35
96-Week (wk) Efficacy and Safety
of Raltegravir (RAL) in Treatmentexperienced Patients
J Gatell1, B-Y Nguyen2, B Grinsztejn3 , C Katlama4,
J Eron5, A Lazzarin6, D Vittecoq7, C Gonzalez8,
M Miller2, H Wan2, J Zhao2, C Harvey2, R Isaacs2, and
The Protocol 005 Team
1 University of Barcelona, Barcelona, Spain; 2 Merck
Research Labs, West Point, PA, USA; 3 Evandro Chagas
Clin Res Inst/Oswaldo Cruz Fndn, Rio de Janerio, Brazil;
4 Hosp Pitie Salpetriere, Paris, France; 5 University of
North Carolina, NC, USA; 6 San Raffaele Sci Inst, Milan,
Italy; 7 Hosp Paul Brousse, Villejuif, France; 8 New York
State Department of Health AIDS Institute, NY, USA
Background: RAL, a HIV integrase inhibitor,
demonstrated potent efficacy in combination with
optimized background therapy (OBT) during the
double-blind (DB) phase of Protocol 005, a phase II
study in patient (pts) failing therapy with triple-class
resistant virus. The study extension provides longterm data on RAL.
Methods: After ≥ 24 wk of DB therapy (RAL 200,
400, or 600 mg bid or placebo (pbo)), all pts were
offered open-label (OL) RAL 400 mg b.i.d. Efficacy
measurements included % pts with HIV RNA (vRNA)
<400 and <50 copies/mL, and change from baseline
in CD4 cells.
Results: 133 pts received RAL and 45 pbo. Baseline
characteristics demonstrated heavily pretreated
patients (~9 years prior ARTs); > 60% of pts had OBT
with limited activity (GSS = 0). All RAL dose groups,
including 94 pts (71%) who entered OL extension,
were combined since all doses were efficacious during
DB therapy; pbo groups data are not reported since
only 6 pts (13%) entered OL. Efficacy is summarized:
39
Week 48
vRNA <400 copies/mL
(95% CI) 2
vRNA <50 copies/mL
(95% CI) 2
Mean ∆CD4 (cells/
mm3) ¶
68% (59, 76)
55% (46, 64)
96 ( 71, 121)
Week 96
55% (46,
64)
48% (40,
57)
104 ( 76,
131)
2
Non-Completer=Failure. N = 133 pts receiving RAL.
¶
Baseline values carried forward for virologic failures
After wk 48, only 9 pts failed with vRNA >50 copies/
mL; 5 of 6 tested had signature integrase mutations
at either Q148 or N155 in combination with other
secondary mutations. RAL was generally well tolerated
with few discontinuations (5 pts) due to AEs.
Conclusions: In pts with limited treatment
options, RAL in combination with OBT had potent
and durable antiretroviral effect through wk 96, and
was generally well tolerated.
Abstract 36
Valacyclovir as Antiretroviral
Therapy
L Negruţiu1, O Roşca1, and M Pop2
1 University of Medicine and Pharmacy “V. Babeş”
Timişoara, Romania, Department of Infectious Diseases I;
2 University of Medicine and Pharmacy “V. Babeş”
Timişoara, Romania, Department of Pediatrics
BACKGROUND: Acyclovir and its prodrug –
valacyclovir – were recently tested in 3 clinical trials
studying their effect on HIV, from the genital fluid of
African persons coinfected with HIV and HSV-2. The
results of these studies were contradictory; two of
them confirming a decrease of HIV concentration in
the seminal fluid, but not in the vaginal fluid; one of
the studies confirmed the decrease of HIV viral load
in plasma and rectal mucous.
with cutaneo-mucous herpetic lesions. We followed
the evolution of the HIV-1 VL in 8 patients (5 females,
3 males) with age between 21-36, HIV+, coinfected
with cutaneo-mucous herpes (first episode): 5 genital
and 3 labial. The patients were under clinic-biological
monitoring for introduction of ART. We monitorised
them repeatedly, before and after Valacyclovir therapy
by:
• quantification of TCD4+ cells by flow cytometry
• VL assessment by PCR-Cobas-Amplicor
• complete blood count: normal
• Elisa HIV-1= +; Elisa HSV2= +; Western-Blot for
HIV-1 +.
The viral load and CD4+ count were repeated 2
months after the interruption of valacyclovir therapy.
The valacyclovir dose: 2x1g/.zi, p.o., 7 days in genital
herpes and 2g ,bid, for 2 days in labial herpes.
RESULTS:
Baseline: - CD4+ cells count: 420-512 cells/mm3
- plasma HIV-1 ARN was: 5000-8500 copies/ml
Repetead: - CD4+ cells count: 620-840 cells/mm3
- plasma HIV-1 ARN: under 50 copies/
ml(undetectable) in 6 cases; 4450-5000 copies/ml in 2 cases with genital herpes
that afterwards presented 3 recurences
under TARV (instituted afterwards)
CONCLUSION: It seems that in some patients
coinfected with HIV-1 and HSV-2 the acyclovir
administered as valinated prodrog can to induce
a decrease in HIV replication, probably by the
phosphorilation of acyclovir by HSV-2 that can
directly inhibit the HIV reverse transcriptase.
Our number of cases is small, representing only some
preliminary results, but our data is in concordance
with older and newer results from the literature.
METHODS: The aim of our research is to study the
reductive effect of valacyclovir on HIV plasmatic viral
load (VL) in 8 HIV-1 positive patients, ARV-naïve,
40
HIV/Hepatitis and
Other Co-infections
41
Abstract 37
The Aging Liver in the HIV
Population
D Dieterich
Mount Sinai School of Medicine, USA
HIV was recognized more than 25 years ago. Since
then, the survival of HIV-infected patients has
increased due to highly active antiretroviral therapy
(HAART) and we now face the long-term complications
of HIV and its treatment. Cardiovascular disease,
bone loss, renal disease, cancer development and liver
disease are recognized more frequently in the HIV
aging population and disease course is accelerated.
(1) The usual causes of liver disease in HIVinfected individuals include chronic viral hepatitis,
steatosis and steatohepatitis, alcohol abuse, drug
hepatotoxicity and cryptogenic cirrhosis. Recently, a
new entity in HIV has been identified: non-cirrhotic
portal hypertension. (2-4) The more frequent clinical
presentation is variceal bleeding and histology is
characterized by hepatoportal sclerosis (HPS) and/
or nodular regenerative hyperplasia (NRH). Prior
exposure to the antiretroviral drug didanosine (ddI)
seems to be the common denominator among the
majority of cases. Pathophysiology of the injury is still
unclear but endothelial lesions of the portal system,
mitochodrial toxicity and microbial translocation
have been suggested. (4) We seek to characterize
liver disease in our HIV aging population, specifically
non-cirrhotic portal hypertension. We plan to
thoroughly assess risk factors and the temporal
relationship between ART exposure / removal and
liver disease, describe clinical presentation, evaluate
diagnostic approaches including liver biopsy and
characterize evolution of liver disease. With the
increasing population of aging HIV, we will encounter
multiple and possibly severe complications of HIV
itself or its treatment, such as non-cirrhotic portal
hypertension.
References:
1. Effros RB, et al. Clin Infect Dis. 2008 Aug
15;47(4):542-53.
2. Maida I, et al. J Acquir Immune Defic Syndr. 2006
Jun;42(2):177-82.
3. Schiano TD, et al. Am J Gastroenterol. 2007
Nov;102(11):2536-40.
4. Maida I, et al. Antivir Ther. 2008;13(1):103-7.
Abstract 38
Co-infection with HCV and HBV:
When and How to Treat?
B Polsky
St. Luke’s-Roosevelt Hospital Center and Columbia
University College of Physicians & Surgeons, New York,
USA
Liver disease has become a leading cause of serious
morbidity and mortality in patients infected with
HIV. The prevalence of HIV/HBV coinfection varies
according to geography and risk category with global
figures estimated in the 8-11% range. In contrast, the
Centers for Disease Control estimates that at least
25% of HIV-infected individuals in the United States
are coinfected with HCV. The occurrence of HCV
coinfection is particularly high (>50%) among HIVinfected injection drug users. Previously, treatment
of HBV and HCV in HIV-infected individuals was not
recommended but with the advent of highly active
antiretroviral therapy (HAART), the prognosis of
HIV-related diseases has dramatically improved.
Thus, the National Institutes of Health has issued
a consensus statement that treatment of HCV
infection in HIV-infected persons is not only possible
but is recommended. Similarly, treatment of HBV
infection in HIV-infected persons is recommended
as progression to cirrhosis in the presence of HBV
is hastened in the context of HIV infection. The
availability of multiple approved agents with and
without overlapping activity against HIV has increased options for physicians and patients and
opened the way for combination therapy for HBV in the
43
context of HIV coinfection. In fact, the most common
nucleos(t)ide backbone (tenofovir/emtricitabine) for
initial HAART is now recommended when treating
HIV/HBV coinfection. Likewise, new investigational
agents against HCV, particularly genotype 1, hold
similar promise and await clinical trial in coinfected
patients.
Abstract 39
Antimicrobial Molecules for
Treatment of Multi-drug
Resistant (MDR) and Extensively
Drug Resistant (XDR) Strains of
Mycobacterium Tuberculosis
R Scott1, D Liu1, M Selbovitz, D Miller2, G Cruz, and
W DeGrado3
1 PolyMedix, Inc., Radnor, PA, USA; 2 AIDS Institute, NY,
USA; 3 University of Pennsylvania School of Medicine,
Philadelphia, PA, USA
BACKGROUND: Pandemic levels of multi-drug
resistant tuberculosis (MDR-TB) and extensively drug
resistant tuberculosis (XDR-TB), with 90% mortality
rate among HIV/MDR-/XDR-TB co-infected, as record
levels of infection occurred in 2007 with 45 countries
reporting at least one case of XDR-TB. A series of
small, stable, synthetically-produced arylamide
antimicrobials has been developed which mimic the
activity of the host defense proteins and represent a
novel class of therapeutics for the clinical treatment of
MDR-/XRD-TB. These small molecules inhibit semidormant tubercule bacilli not inhibited by other TB
drugs. The compounds work by directly lysing bacterial
cell membranes, the same mechanism utilized by the
host defense proteins. As a result, resistance to these
compounds is highly unlikely to develop. Previous
attempts to develop host defense proteins have failed
due to inactivity in vivo, manufacturing problems,
poor stability, and immunogenic responses; but these
non-protein drugs avoid such limitations.
44
METHODS: Six molecules spanning several structural series were screened by the Tuberculosis
Antimicrobial Acquisition and Coordinating Facility
using in vitro assays to measure susceptibility against
H37Rv strain of M. tuberculosis and cytotoxicity to
monkey VERO cells. RESULTS: Three of the tested antimicrobial compounds exhibited high antimicrobial activity
(IC90 < 5 µg/ml) against the H37Rv strain of M.
tuberculosis, with selectivity greater than 30-120
fold for TB versus mammalian cells. The synthetic
small molecules rapidly killed the M tuberculosis
cells in vitro. These compounds are stable and not
immunogenic. The results indicate they may be
successful treatment for MDR and XDR strains of M.
tuberculosis.
CONCLUSIONS: Results indicate that synthetic smallmolecule mimics of the host defense proteins may be
an effective treatment against strains of MDR-/ XDRTB. Existing knowledge of the mechanism of action
through which these compounds work gives reason
to believe that there is a lower risk of resistance
developing to them. Further in vitro tests to measure
susceptibility of isoniazid, rifampicin, fluoroquine,
capreomycin, icanamycin, and amikacin- resistant
strains to these compounds will be initiated. The lack
of financial mechanisms committed to facilitating
the development of new treatments is exacerbating
the spread of MDR-/XDR-TB complicated by HIV
infection.
Abstract 40
Progressive Multifocal
Leukoencephalopathy – A Case
Report
O Roşca1, EC Roşca2, M Pop3, and L Negruţiu1
1 University of Medicine and Pharmacy “Victor Babeş”
Timişoara, Romania, Department of Infectious Diseases I;
Timişoara, Romania, Department of Neurology;
Timişoara, Romania, Department of Pediatrics
BACKGROUND: Progressive multifocal leukoencephalopathy (PML) is a progressive demyelinating
disease caused by JC virus, occurring in
immunocompromised patients. In the HAART era,
approximately 5% of the AIDS patients have been
reported to develop PML. The clinical presentation
of PML is quite variable because lesions may occur
anywhere in the CNS white mater; the most common
findings are motor weakness, visual defects (e.g.
visual blurring, diplopia), and incoordination. The
most frequently affected regions are the cerebral
hemispheres, followed by subtentorial lesions. The
diagnosis of PML in an immunocompromised patient
with evocative clinical picture of focal neurologic
deficits is made by demonstrating typical findings
on brain imaging studies and detection of viral DNA
in CSF by PCR examination. Brain biopsy should
be reserved for cases with suspicious white matter
lesions on CT or MRI in which JC virus is not detected
in PCR. Differential diagnosis should consider other
primary as well as opportunistic infections of CNS,
other demyelinating diseases (such as multiple
sclerosis), vascular lesions (e.g. ischemic stroke, HIV
vasculopathy), tumors (e.g. lymphoma) and HIV
encephalopathy with secondary changes in white
matter.
METHODS: The present paper describes the case of
a HIV positive patient with clinical, biological and
imaging findings highly suggestive for PML, but
negative PCR for JC virus DNA.
RESULTS: The neurological examination revealed
somnolence, confusion, left pyramidal signs, left
hypotonia, incoordination of the left limbs, left
oculomotor nerve palsy, left lower facial weakness and
dysartria. The MRI scan revealed diffuse lesions up to
1,5 cm situated in the left internal capsula, left pons
and midbrain, vermis and left cerebellar hemisphere
with minimal gadolinium enhancement, no mass
effect and no edema. The lesions were hypointense
on T1-weighted images and hyperintense on T2weighted and Flair. The biological investigations were
highly suggestive for PML, but JC virus DNA was not
detected in CSF. The status of the patient improved
under HAART therapy.
CONCLUSION: Before the HAART era, JCV PCR had
a high sensitivity and specificity for the diagnosis of
PML, but over the past few years it has become more
frequent to find negative CSF JCV PCR results in AIDS
patients with clinical and radiological presentation
indistinguishable from PML. However, a negative
PCR test does not exclude this diagnosis. In these
patients, a definitive diagnostic necessitates a brain
biopsy, an invasive method not without risks, which
sometimes might not be accepted by the patients,
especially if their status is improving under therapy.
The present data suggest that there is a need for the
development of new diagnostic methods, with higher
sensitivity, in concordance with the recent changes in
the disease’s evolution.
Abstract 41
Accelerated Approval and Postmarketing Commitments:
A Delicate Balance
T Swan
Treatment Action Group, New York, NY, USA
“Access to promising new drugs is a right one cannot
deny patients with a fatal illness. However, this
right carries with it the responsibility to provide
information that will advance science and help future
45
generations of patients.” Carlton Hogan 1961-20031
Background: AIDS activists have focused on HIV
drug development for more than two decades. In
1992, in part due to pressure from AIDS activists
and pharmaceutical deregulators, FDA instituted
Accelerated Approval regulation, allowing earlier
approval of drugs for serious, or life-threatening
diseases, based on unmet need and a surrogate
endpoint. Clinical benefit and questions about
optimal use are determined in subsequent trials,
known as post-marketing commitments (PMCs).
biologic agents likely to be used in children, these
often lag far behind target completion dates.
AIDS activists welcomed accelerated approval, but
pressed for collection of data on pharmacokinetics,
drug-drug interactions, dosing, efficacy and toxicity
by disease stage, and in specific populations, during
registration trials. They argued that post-marketing
commitments are not always required or conducted
expeditiously. Often, PMC results are not available
until drugs have already been on the market for
years.
MedWatch data and medical literature were reviewed
for instances when emergent safety and toxicity issues
would have warranted studies in, or greater inclusion
of, specific populations in clinical trials of novel
antiretroviral agents or treatments for comorbidities
prevalent among people living with HIV/AIDS.
Valid scientific rationale, justice (as outlined by the
Office of Human Subjects Research’s 1974 Belmont
Report2), and HIV demographics in the United States
argue for adequate enrollment of women, people of
color, and current and former injection drug users
in registration trials. Updated demographic data on
HIV prevalence in the US indicate that ~25% women
constitute ~25% of cases, African Americans a
staggering 46%, Hispanics, ~17%, and injection drug
users ~18%3.
Methods: FDA’s post-marketing database was
extensively reviewed to assess the status of ongoing
and outstanding post-marketing commitments,
when available (for tirpanavir, atripla, darunavir,
didanosine EC, etravirine, emtricitibine/tenofovir,
epivir/abacavir, epivir/retrovir/abacavir, invirase,
mariviroc, nevirapine, and raltegravir), to assess
instances of unacceptable delay.
Conclusion: Specific examples are described, such
as late characterization of sex-specific adverse events
and life-threatening drug-drug interactions.
Inadequate enrollment of women in HIV clinical
trials has been a chronic—and dangerous— problem.
Failure to perform drug-drug interaction studies on
methadone and buprenorphine, agents used for opiate
substitution treatment, and hormonal contraceptives,
as well as using liver enzyme elevations as exclusion
criteria in the absence of a compelling rationale,
has resulted in the virtual exclusion of women and
patients coinfected with viral hepatitis from many
early-phase clinical trials of novel antiretroviral
agents, when signals on differences in PK and toxicity
might emerge. Although the 2003 Pediatric Research
Equity Act (PREA) requires studies of drugs and
46
Novel Therapeutic Approaches:
Antiviral Mechanism and
Predictive Toxicology
47
Abstract 42
Optimizing HAART Therapy in
the Era of Integrase and Entry
Inhibitors
C Katlama
Hopital Pitie-Salpétrière, Paris; COREVIH Paris; Pierre et
Marie Curie University Paris VI, France
Combined antiretroviral therapies have revolutionized the prognosis of HIV disease transforming an
almost uniformly lethal disease in a chronic one with
an estimated survival of several decades on effective
antiretroviral therapy. However several issues had
tempered this “idyllic” situation: cART cannot be
stopped without damages such as an increases in
number of deaths, comorbidities even at relatively
high ratio of CD4 demonstrating that HIV is not
only deleterious by its consequences on immune
deficit but also in the fact that it promotes high
immune activation that follows the rebound in HIV
replication- cART at least NRTIs and PIs is associated
with toxicities and comorbidities.
This leads to investigate new strategies opening a
new field of research to be able to maintain long-life
therapy which will retain a full viral efficacy with a
plasma viral load permanently below 50 copies /ml, a
cut-off which has been associated to durability of the
control of viral suppression , the absence of clinicallyrelevant development of viral resistance at least in
plasma with a minimum induced toxicity, a mandatory
issue for chronic administration over decades at
all periods of life. These strategies may involve the
existing classes of drugs trying to build drug-class
sparing
maintenance strategies. Maintenance
strategies with protease inhibitor monotherapy
is currently investigated mainly with lopinavir or
darunavir under investigation in randomized studies.
The development of new classes of drugs had already
brought significant improvement in HIV disease
management. Integrase inhibitors mainly the recently
licensed raltegravir had lead to increase the rate of full
viral suppression in salvage patients in combination
with new drugs from old classes such as darunavir or
etravirine and allowed up to over 80% of plasma HIV
RNA < 50 copies/ml. Inhibitors of coreceptors CCR5
mainly maraviroc are not only antiretroviral agents but
appears also to have immune modulatory functions
with specific action on CD4 lymphocytes, immune
activation or potentially on apoptosis. Because these
drugs act on different viral targets, because of their
different resistance and toxicity profile from NRTIs
or PIs, clinical research has to explore their potential
role in the treatment gaps.
Several important questions throughout remain to be
explored:
• What is the role of these new drugs in primary
infection?
• How can both raltegravir with its very rapid
decrease in viral load and maraviroc with its
action on CD4 decrease the delay needed time
to control the virus and the time to restore CD4
above 200/mm3 in late HIV presenters?
• How can these drugs be used in maintenance
therapy in patients with undetectable viral load
but a long history with subsequent toxicities of
PIs or NNRTIs? Can we limit the number and the
burden of drugs used to control viral replication?
• Will these drugs in addition to classic cART be
capable to decrease viral reservoirs and why not
tends towards eradication?
49
Abstract 43
IDX899 - A Novel Once-a-day
Second Generation NNRTI for the
Treatment of HIV/AIDS
D Mayers1, R Murphy2, C Zala3, XJ Zhou1, M. Seifer1,
JJ Jakubik1, K Pietropaolo1, M-F Temam4, B Belanger1,
J Sullivan-Bolyai1, and DN Standring1
1 Idenix Pharmaceuticals, Inc., Cambridge, USA;
2 Northwestern University Feinberg School of Medicine,
Chicago, USA and Pierre et Marie Curie Université -Paris
6, Paris, France; 3 ACLIRES Argentina, Buenos Aires,
Argentina; 4 Idenix Pharmaceuticals, Inc., Montpellier,
France
Background: IDX899, a second generation
NNRTI, has potent in vitro antiviral activity against
wild-type HIV-1 and remains active against many
viruses bearing mutations selected by other first or
second generation NNRTIs. In particular, IDX899
showed good activity against most HIV-1 isolates
selected in vitro by efavirenz or etravirine, including
isolates carrying as many as four or five resistance
mutations conferring high level resistance to the
respective selection agent. In vitro, IDX899 selected
mutations in the reverse transcriptase gene including
V90I, E138K, Y181C/I, S134I, I135R, G190E and
M230L, and two primary pathways to IDX899
resistance were identified, starting with either E138K
or Y181C changes. Compared to efavirenz, prolonged
passaging and multiple mutations were required to
confer high level resistance to IDX899. The favorable
in vitro resistance profile of IDX899, together with its
PK properties, suggests that IDX899 should display
a high barrier to resistance in the clinical setting.
Favorable clinical safety and pharmacokinetics
in healthy volunteers supported a phase 1b/2a
study which assessed antiviral activity, safety and
pharmacokinetics of daily (QD) IDX899 in treatmentnaïve HIV-1-infected subjects.
or placebo QD for 7 days. HIV-1 RNA levels were
measured using the HIV-1 Roche COBAS Amplicor®
1.5 assay. IDX899 plasma levels were quantitated
using a validated LC/MS-MS method. The protocol
enrolled 40 subjects (37 men and 3 women) with mean
baseline CD4+ of 479 cells/mL and baseline viral load
of 4.71 log10 copies/mL. Subjects were infected with
HIV-1 clades B or B/F.
Results: The mean log10 decreases in HIV-1 plasma
RNA from baseline to Day 8 were 1.78, 1.78, 1.84
and 1.87 in the 800, 400, 200 and 100 mg cohorts,
respectively. The placebo group showed a 0.10 log10
increase. Steady-state trough concentrations well
exceed the in vitro protein-binding adjusted EC50 and
EC90 of IDX899 for all doses evaluated; consistent
with the observed absence of a PK/PD relationship.
There were no treatment discontinuations, treatment
emergent SAEs or dose-limiting toxicities. No
discernable patterns in adverse events or laboratory
abnormalities were observed. Drug-drug interaction
studies of IDX899 combined with either Truvada® or
atazanavir in healthy volunteers have demonstrated
no evidence of clinically significant interactions.
Conclusion: Once daily oral IDX899 was well
tolerated, demonstrated potent HIV-1 antiviral
activity at low doses, and has shown no clinically
significant drug-drug interactions to date. IDX899
offers the potential for treatment of both treatmentnaïve and treatment-experienced HIV-infected
persons, along with the potential for co-formulation
with other antiretroviral drugs.
Methods: Enrolled subjects had HIV-1 RNA ≥ 5,000
copies/mL and CD4+ cell count ≥ 200 cells/mm3. Ten
subjects per sequential dose cohort were randomized
(8:2) to receive IDX899 (800, 400, 200 or 100 mg)
50
Abstract 44
Vicriciroc: A Next-generation
CCR5 Antagonist for Treatment of
HIV
LM Dunkle
Schering-Plough Research Institute, USA
Vicriviroc (VCV) is a specific antagonist of the CCR5
chemokine receptor and is a potent inhibitor of the
entry of R5-tropic HIV into uninfected cells, thereby
reducing replication of HIV. In vitro and in vivo studies
have demonstrated potent additive-to-synergistic
activity of VCV in combination with most other
classes of antiretroviral agents (ARVs). In addition,
VCV shares no cross-resistance with other classes of
ARVs. As the envelope mutations that confer viral
resistance to the CCR5 antagonist class have not
been fully characterized, it is not clear whether crossresistance exists between VCV and other members of
the class, e.g. maraviroc. It is clear that resistance to
VCV develops slowly in vitro and very infrequently in
vivo. As VCV has no activity against CXCR4-tropic
HIV, clinical trials have focused largely on subjects
with R5-tropic virus. When X4-tropic virus becomes
detectable, usually as the result of variability in the
tropism assay or “uncovering” of pre-existing X4
virus, viral suppression is maintained to the extent
that adequate numbers of active ARVs, including a
PI/r, are in the background regimen.
VCV has been studied in three Phase 2 trials (2 in
treatment-experienced and one in treatment-naïve
individuals). The pharmacokinetics of VCV are very
predictable, and no dose adjustment is required when
used as currently recommended. A single dose of 30
mg once daily is appropriate in a regimen containing
a PI/r in both first-line and treatment-experienced
settings. Pharmacokinetic/pharmacodynamic analyses support 30 mg QD as the dose that most
likely achieves the trough concentration of 100 ng/
mL, above which full and durable viral suppression
is observed. This target concentration was not as
reliably achieved with lower dose levels of VCV. The
safety profile in all recent studies has been promising,
including absence of seizures and hepatotoxicity,
malignancy rates comparable to background rates in
advanced HIV disease and no increased infections,
AIDS-defining events or ischemic cardiovascular
events.
Current Phase 3 studies, now fully enrolled globally,
focus on the treatment-experienced population.
Another Phase 2 study of VCV in a first-line regimen
is on-going. All Phase 3 studies include a newly
optimized background regimen that includes a PI/r
as is standard in treatment-experienced subjects. The
ongoing Phase 2 study explores a novel, class-sparing
treatment paradigm combining VCV with boosted
atazanavir in comparison with a standard first-line
regimen of Truvada + boosted atazanavir. The studies
and enrolled populations will be described fully.
In conclusion, the clinical development program of
VCV has progressed to full enrollment of Phase 3
in treatment-experienced subjects and of the first
stage of the Phase 2 first-line therapy study. The
pharmacokinetic, efficacy and safety profiles of VCV
are robust and support a single 30 mg once daily dose
in regimens containing a PI/r.
Abstract 45
Amdoxovir Combined with Low
Dose AZT for HIV-1 Therapy
RL Murphy and the RFS-AMDX-203 Team
Northwestern University, Chicago, IL, USA
Background: Amdoxovir (DAPD) is a NRTI that is
synergistic in human lymphocytes with zidovudine
(ZDV), and in combination prevents selection of TAMs
and K65R mutations. ZDV, the first effective NRTI
developed for HIV has well characterized hematologic
toxicities. In silico, ZDV (200 mg bid) produces reduced
ZDV-monophosphate levels, associated with toxicity,
while maintaining ZDV-triphosphate levels necessary
51
for antiviral effect. The objective was to evaluate the
pharmacokinetics (PK) and anti-HIV activity of DAPD
with and without ZDV at two doses, as a prelude to
advanced phase 2 studies.
Methods: Twenty-four subjects, not receiving
antiretroviral therapy and with plasma HIV-1 RNA
(viral load, VL) ≥ 5,000 copies/ml, were randomized
to DAPD 500 mg bid, DAPD 500 mg plus ZDV 200 or
plus ZDV 300 mg bid for 10 days. In each arm, subjects
were randomized 3:1 to DAPD or placebo. VL was
determined daily, and PK sampling was performed
on Days 1 and 10. Analyses were performed using
an intent-to-treat approach. The mean change in VL
log10 from baseline at Day 10 and cumulative change
in VL log10 from baseline to day 10 (AUCVL) were
determined. Plasma DAPD, dioxolane guanosine
(DXG) metabolite, and ZDV levels were measured by
LC-MS/MS. Safety was evaluated by proportion of ≥
Grade 3 adverse events per treatment, using ACTG
toxicity grading scale. ANOVA was performed to
relate AUCDXG and AUCZDV with AUCVL.
Results: On day 10, mean VL log10 change was
+0.10 with placebo, -0.65 with ZDV 200, -0.45 with
ZDV 300, -1.07 ± 0.80 with DAPD, -1.97 ± 0.16 with
DAPD/ZDV 200, and -1.67 ± 0.21 with DAPD/ZDV
300. DAPD/ZDV 200 was significantly more potent
than DAPD (p < 0.04), suggesting synergy, and there
was markedly decreased VL variability with DAPD/
AZT compared with DAPD alone. VL decline was
significantly improved with DAPD/ZDV 200 and 300
mg compared with ZDV monotherapy (p ≤ 0.0001).
Adverse events were mild to moderate and transient.
As anticipated, no statistically significant drug-drug
interactions were noted (see also Asif et al, HIVDART, 2008).
Conclusions: DAPD and DAPD/ZDV were well
tolerated, and the combination produced a 2 log VL
reduction after 10 days. The profound and consistent
decrease in VL variability with DAPD/AZT compared
with DAPD alone suggest strong in vivo synergy. The
lack of correlation between variations in plasma
AUCZDV with VL decline supports in silico findings
(Antimicrob Agents Chemother, December 2008).
52
The need of additional purine anti-HIV nucleosides,
especially guanosine analogs to replace abacavir
warrants further development of co-formulated
DAPD/ZDV for therapy of HIV infections.
Abstract 46
A New Era in HIV-antiretroviral
Therapy: Darunavir, Etravirine
and TMC278
E Lefebvre
Tibotec, Amsterdam, the Netherlands
Since the development of HAART, the prognosis for
HIV-1-infected patients has improved dramatically.
However, there remains a need for new antiretroviral
agents with improved efficacy, convenience, tolerability
and resistance profiles for both treatment-naïve
and -experienced patients. J&J/Tibotec is currently
developing innovative antiretroviral therapies to
meet the needs of HIV-1-infected patients.
The PI darunavir (DRV; PREZISTA™), administered
with low-dose ritonavir (DRV/r) demonstrates
efficacy and tolerability in both treatment-naïve and
-experienced patients. In the Phase III ARTEMIS trial,
treatment-naïve patients were randomised 1:1 to
receive DRV/r 800/100mg qd (n=343) or lopinavir/r
(LPV/r) 800/200mg total daily dose (n=346), both
with TDF/FTC qd, for up to 96 weeks. At Week 96,
significantly more patients receiving DRV/r than
LPV/r achieved virological response <50 copies/
mL (ITT-TLOVR) (79% vs 71%), establishing both
non-inferiority (p<0.001) and superiority (p=0.012)
of DRV/r over LPV/r. DRV/r response rates were
superior to LPV/r in patients with high baseline
viral load (p=0.023) and low baseline CD4 count
(p=0.009). Fewer patients receiving DRV/r than LPV/r
discontinued due to an adverse event (AE) (4% vs 9%).
Grade 2–4 treatment-related diarrhoea occurred less
frequently with DRV/r than with LPV/r (4% vs 11%,
p=0.0006). In addition, for treatment-experienced
patients in TITAN at 96 weeks, approximately half
as many patients receiving DRV/r had virological
failure than those receiving LPV/r (14% vs 26%) and
less virological failures receiving DRV/r than LPV/r
developed primary PI (18% vs 35%) or NRTI (10% vs
28%) mutations.
Etravirine (ETR; INTELENCE™) is a next-generation
NNRTI with activity against NNRTI-resistant
HIV-1. In the ongoing Phase III DUET-1 and -2
trials, treatment-experienced patients with NNRTI
resistance were randomised 1:1 to receive ETR
(n=599) or placebo (n=604), with investigatorselected NRTIs and optional enfuvirtide. At Week 48,
virological response (50 copies/mL; ITT-TLOVR) was
significantly greater with ETR than with placebo (61%
vs 40%, p<0.0001), and also for patients with ≥2 active
agents (78% vs 67%, p=0.0022) or no active agents
in their background regimen (46% vs 6%, p<0.0001).
Fewer patients in the ETR arm experienced an AIDSdefining illness/death than those in the placebo arm
(6% vs 10%, p=0.0408). The safety and tolerability
profile of ETR was comparable to placebo with the
exception of rash, which was mild-to-moderate in
severity and resolved on continued treatment.
The efficacy and safety of the investigational nextgeneration NNRTI, TMC278, is being investigated
in TMC278-C204, a five-year Phase IIb dose-ranging
study in treatment-naïve patients. Patients were
randomised 1:1:1:1 to receive efavirenz 600mg qd
(EFV; n=89) or TMC278 qd (25mg [n=93], 75mg
[n=95] or 150mg [n=91]). Patients also received 2
NRTIs. TMC278 demonstrated a potent and sustained
virological response (<50 copies/mL; ITT-TLOVR) to
96 weeks similar to that achieved with EFV (71–76%
vs 71%).
Mean CD4 cell count increased continuously from
baseline during the trial and was similar across groups
at Week 96 (146–172 vs 160 cells/mm3). TMC278
demonstrated tolerability benefits over EFV, with
lower incidences of rash (TMC278 combined group:
9% vs EFV: 21%, p<0.01), nervous system (31% vs
48%, p<0.01) and psychiatric events of interest (16%
vs 21%, p=0.26) and smaller lipid elevations.
With their efficacious and well-tolerated dosing
regimens, DRV, ETR and TMC278 take antiretroviral
therapy into a new era, further enhancing the lives of
HIV-1-infected patients. An anti-tuberculosis drug,
TMC207, is also in development, expanding the range
of new anti-infective agents.
Abstract 47
Low Potential for Class Related
Toxicity of Next Generation
Nucleotide Analog GS-9148
AS Ray1, G LaFlamme1, D Grant1, R Fisher2, AC Carey1,
JE Vela1, RL Mackman1, and T Cihlar1
1 Gilead Sciences, Inc., Foster City, CA, USA; 2 Vitron,
Inc., Tucson, AZ, USA
BACKGROUND:
Nucleoside
and
nucleotide
reverse transcriptase inhibitors (N(t)RTI) are an
important component of highly active antiretroviral
therapy (HAART). However, the durability of N(t)
RTI containing regimens can be limited by the
emergence of drug resistance and side-effects. Two
N(t)RTI class related mechanisms of toxicity include
mitochondrial damage caused by inhibition of the
mitochondrial DNA (mtDNA) polymerase gamma and
nephrotoxicity resulting from transporter mediated
renal accumulation. GS-9131 is a phosphonamidate
prodrug of the 2’-deoxyadenosine monophosphate
analog GS-9148. GS-9148 has been shown to have
a favorable resistance profile against common N(t)
RTI mutations (including M184V, L74V, K65R, and
thymidine analog resistance mutations). In order to
better understand the potential for side-effects, GS9148 was tested for N(t)RTI class related toxicities.
METHODS: Effects on mtDNA were assessed in vitro
in up to 21 day assays with the liver cell line HepG2.
Depletion of mtDNA and chromosomal DNA were
measured by sequential DNA hybridization with
probes for the cytochrome b and 18S rRNA genes,
respectively. Inhibition of mtDNA polymerase
gamma by nucleoside triphosphate analogs was
53
measured using activated calf thymus DNA as a
template. Accumulation of N(t)RTI were studied in
cells overexpressing the human influx transporters
organic anion transporter 1 and 3 (hOAT1 and hOAT3)
and the efflux transporter multidrug resistance
protein 4 (MRP4) as well as freshly isolated human
renal cortex tissue. In order to determine the net
effect of interactions with renal transports on kidney
accumulation and renal clearance in vivo, beagle dogs
were administered [14C] GS-9131 at a dose of 3 mg/
kg (10 µCi/kg) and kidney tissue and urine collected
over 24 hours.
RESULTS: Treatment of HepG2 cells with GS-9148
did not result in a selective depletion of mitochondrial
DNA and GS-9148-diphosphate was found to have
an inhibitory constant (IC50) of >300 µM for mtDNA
polymerase gamma. GS-9148 was transported 60- to
100-fold less efficiently than acyclic nucleotides by
the renal uptake transporter hOAT1. GS-9148 was
also an inefficient substrate for hOAT3. In contrast,
GS-9148 was effectively transported by the renal
efflux transporter MRP4. Consistent with molecular
transport studies, GS-9148 was found to have low
net active tubular secretion and low accumulation in
the kidneys of dogs administered [14C] GS-9131. GS9148 was also inefficiently taken up by human renal
cortex tissue in vitro.
CONCLUSIONS: The aging of the HIV infected
population and the potential of treatment for the
duration of a normal life span raise new challenges for
HIV therapy. In addition to potency and durability,
the long term safety profile of HAART combinations
are of critical importance. GS-9131 is a promising
next generation N(t)RTI currently in early clinical
trials with a low potential for N(t)RTI class related
toxicities caused by mitochondrial damage or renal
accumulation.
54
Abstract 48
Mechanisms Associated
with Delayed HIV RT Chaintermination
E Tchesnokov1, A Obikhod2, RF Schinazi2, and M Götte1
1 McGill University, Montreal, Quebec, Canada; 2 Emory
University School of Medicine/VA Medical Center,
Atlanta, GA, USA
BACKGROUND: Entecavir (ETV) is a potent antiviral
drug to treat infection with the hepatitis B virus
(HBV). Recent studies have shown that ETV has antiHIV activity and can select for the M184V mutation
in HIV-1 reverse transcriptase (RT), which limits
its clinical use in HIV/HBV co-infected individuals.
However, the mechanism of drug action remains
elusive. ETV is a guanosine nucleoside analogue that
contains a 3’-hydroxyl group. Thus, the incorporated
ETV-5’-monophosphate (ETV-MP) does not act
as a classic chain-terminator. Here we utilized
various biochemical tools to elucidate the anti-HIV
mechanism of ETV and its implications with respect
to major resistance pathways against established
nucleoside analogue RT inhibitors (NRTIs)
METHODS: We used a variety of biochemical
approaches, including enzyme kinetics, binding
studies, and high resolution footprinting experiments
to assess the major contribution to ETV-mediated
inhibition of DNA synthesis.
RESULTS: Incorporation of ETV-MP at position n
causes RT pausing at positions n and n+3. Increasing
concentrations of natural dNTP pools at positions n+1
and n+4 can eventually overcome enzymatic pausing;
however, incorporation of the natural nucleotide
at position n+4 is severely compromised. Kinetic
measurements revealed a subtle 8-fold decrease in
efficiency of nucleotide incorporation at position
n+1 when ETV-terminated primers are compared
with the natural counterpart, while nucleotide
incorporation at position n+4 is reduced by three
orders of magnitude (1230-fold). High-resolution
footprinting experiments show that complexes
with HIV-1 RT and a primer/template that mimics
the latter situation are as stable as complexes that
contain natural primers. Rather, ETV-MP forces the
enzyme to slide away from the 3’-end of the primer at
position n+3, which provides a plausible mechanism
for such “delayed chain-termination”. RT enzymes
with thymidine analogue associated mutations
(TAMs) can efficiently excise the incorporated
ETV-MP at position n, as demonstrated for several
established NRTIs. However, ETV is fully sensitive
against TAMs containing HIV variants, which shows
that the additional nucleotides at positions n+1 to
n+3 protect the inhibitor from excision.
CONCLUSION: The results of this study demonstrate
that “delayed chain-termination” at position n+3
is the dominant mechanism of action of ETV. The
combined data provide a rationale for the development
of ETV-like, delayed chain-terminators as anti-HIV
compounds that can evade the excision mechanism.
Abstract 49
Acyclovir as an HIV-RT Inhibitor
in Herpesvirus-infected Human
Tissues
L Margolis
National Institute of Child Health and Human
Development, Bethesda, MD, USA
Background: The emergence of drug-resistant
viruses necessitates the discovery of new efficient
anti-HIV drugs. that should also be inexpensive, in
order to be available in limited-resource countries.
Such an efficient and inexpensive drug exists for
human herpesviruses (HHVs): acyclovir (ACV) is
particularly active against α-HHVs but also inhibits,
although with lower potency, the replication of the
β- and γ-HHVs. Its exclusive anti-herpetic specificity
is primarily based on the unique ability of herpesviral
kinases to phosphorylate ACV into active ACVtriphosphate, a property that makes ACV inactive
against other viruses, including HIV-1. Here, we
report on a newly found direct activity of ACV on HIV1 in human tonsillar, lymph node, rectal, and genital
tissues coinfected with various HHVs, and we provide
a molecular mechanism for this phenomenon.
Methods: Tonsillar, lymph node, rectal and cervical
tissues as well as isolated cells were infected ex vivo
with HIV-1 and treated with ACV or ACV derivatives.
Viral replication was evaluated with real-time PCR
and ELISA, and HIV-1 RT activity was measured in a
cell-free system using a gel-based assay.
Results: ACV efficiently suppresses replication of
HIV-1of various subtypes in human tonsillar, lymph
node, vaginal, and rectosigmoid tissues ex vivo if and
only if they carry one or several herpesviruses. ACV
did not inhibit HIV replication in an HHV-free cell
line. However, when HHV-6-infected cells were added
to the HIV-1-infected cultures, ACV became an HIV1 suppressor. ACV-triphosphate (ACV TP; formed in
HHV-infected tissues), but not ACV, suppresses RT;
it is incorporated into the HIV DNA nascent chain,
causing its obligate termination. Phosphorylated
ACV-based prodrug suppresses HIV in HHV-free
cells.
Conclusions: In human tissues coinfected with
various herpesviruses. including low-pathogenic
HHV-6 and HHV-7, ACV is activated into an HIV
RT inhibitor and suppresses HIV-1. ACV-phosphate
prodrugs bypass the requirement for phosphorylation
by herpesvirus kinases to become HIV-1 inhibitors.
ACV may directly suppress HIV in humans already
infected with one or several herpesviruses that can
activate ACV. Our results suggest that ACV may be
therapeutically beneficial for various HIV-1-infected
patients, since the majority of humans are already
infected with HHV-6, often together with other
HHVs that activate ACV. However the use of ACV
against HSV-2 in HIV-infected patients may select
for HIV-1 variants resistant to other antiretrovirals.
ACV and its prodrugs represent a new class of HIV RT
inhibitor. In general, the use of one resident microbe
to convert an inactive compound into an inhibitor
of another pathogen constitutes a new therapeutic
55
principle against human pathogens, in particular HIV.
In the case of ACV, its low toxicity and low cost make
it potentially applicable for HIV treatment, possibly
in combination with other drugs.
Abstract 50
Comparison of Two Human
Pancreatic Cell Lines for
Predicting Mitochondrial Toxicity
by Nucleoside Analogs
L Bassit, J Cohen, A Obikhod, E Lee, and RF Schinazi
Center for AIDS Research, Department of Pediatrics,
Emory University School of Medicine, and Veterans
Affairs Medical Center, Atlanta, GA, USA
Background: Mitochondrial (mt) toxicity is a
growing cause for concern in preclinical candidate
failures, as well as post-market drug withdrawals.
Several predictive cell-based models for cytotoxicity
are currently available for experimental evaluations
of novel antiviral agents, but different parameters
can influence their performance and predictability
in humans. For prediction of pancreatitis by NRTI,
few studies have examined mt cytotoxicity in
human pancreatic adenocarcinoma cellular systems.
Therefore, in this study, PANC1 cells of pancreatic
ductal adenocarcinoma origin were compared with
the CAPAN1 cells of both ductal and acinar origin as
well as the formation of NTP, to enable monitoring
for early pancreatic cytotoxicity.
Methods: Mt toxicity of D-D4FC (dexelvucitabine),
tenofovir disoproxil fumarate (TDF), and tenofovir
(TFV) was evaluated for their potential DNA
polymerase γ-inhibiting capacity, using the two
cell lines. Cells were seeded at 5,000 c/well and test
compounds were added at various concentrations.
Following 14 days incubation, total cellular DNA was
isolated, and both mtDNA and nuclear DNA (nDNA)
were amplified in parallel in a real-time PCR.
56
Results: There was a clear difference between the cell
lines with respect to both mt- and nDNA polymerase
γ-inhibition by NRTI. CAPAN1 cells appeared to be
more sensitive since D-D4FC caused selective mtDNA
toxicity with an IC50 of 4.3 µM; toxicity was ~8-fold
higher as compared to PANC1 cells. In addition, TDF
caused reduction in both mt- and nDNA, with IC50
in CAPAN-1 cells of 9.0 ± 1.8 µM and 8.0 ± 1.0 µM,
respectively; it was slightly more toxic for mtDNA
(~2-fold increase) and even more toxic for nDNA (~3fold increase). TFV at 10 µM did not show signs of
toxicity for either mt- or nDNA in the two pancreatic
cell lines. ddC used as a positive control, showed both
mt and nDNA toxicity effects in CAPAN1 cells with
an IC50 of 0.2 ± 0.2 µM and 5.8 ± 0.9 µM, respectively,
whereas in PANC1 cells, ddC showed selective
toxicity for mtDNA (9-fold lower as compared to
CAPAN1). No apparent toxicity was observed for the
negative control 3TC at 50 µM in the two cell lines.
The NTP levels for 3TC, TDF, and D-D4FC at 10 µM
after 4 hr incubation was overall higher in PANC1
than CAPAN1 cells. All three drugs were efficiently
phosphorylated in PANC1 and CAPAN1 cells. The
intracellular concentration of TDF-DP was on average
25 times higher than concentration of either 3TC-TP
or D-D4FC-TP in both cell lines. These results suggest
that in these cell lines, there was no direct relationship
between drug phosphorylation and mitochondrial
toxicity.
Conclusions: CAPAN1 cells appear to provide the
most reliable in vitro assessment of NTRI-associated
mt toxicity for early prediction of pancreatitis. The
results may help to explain cellular specific toxicity
observed by nucleoside analogs used in HIV treatment.
Based on these findings, we conclude that CAPAN1 is
a more suitable cell line to study NRTI antiretroviral
agents than PANC1 cells.
Abstract 51
ARTEMIS: Efficacy and Safety
of Darunavir/ritonavir (DRV/r)
800/100 mg Once-daily vs
Lopinavir/ritonavir (LPV/r) in
Treatment-naïve, HIV-1-infected
Patients at 96 Weeks
D Jayaweera1, R Ortiz2, A Mills3, J Morales-Ramirez4,
I Dierynck5, V Sekar6, C Vanden Abeele5, G De La Rosa7,
and L Lavreys5
1 University of Miami, Miami, FL, USA; 2 Orlando
Immunology Center, Orlando, FL, USA; 3 Los Angeles,
CA, USA; 4 Clinical Research Puerto Rico, Inc., San Juan,
PR, USA; 5 Tibotec BVBA, Mechelen, Belgium;
6 Tibotec Inc., Yardley, PA, USA; 7 Tibotec Therapeutics,
Bridgewater, NJ, USA
Background: ARTEMIS is a randomized, controlled, open-label, 192-week Phase III trial in HIV-1infected treatment-naïve patients, comparing oncedaily darunavir/r (DRV/r) to lopinavir/r (LPV/r), both
given with fixed-dosed tenofovir/emtricitabine (TDF/
FTC). We report the efficacy, safety and tolerability of
DRV/r and LPV/r at Week 96.
Methods: Patients with HIV-1 RNA (VL) ≥5000
copies/mL were randomized to DRV/r 800/100mg
once-daily or LPV/r 800/200mg total daily dose, plus
TDF/FTC (300/200mg) and stratified by baseline
viral load and CD4 count. The primary objective was
to evaluate for non-inferiority of DRV/r to LPV/r
(delta -12%) in confirmed VL <50 copies/mL (ITTTLOVR) at Week 48. DRV/r superiority (delta 0%)
was assessed if non-inferiority was shown. Safety and
tolerability were also assessed.
95% CI: 2, 15; P<.001) and demonstrating superiority
(P=.012). Among patients with high baseline VL
(≥100,000 copies/mL), virologic response was
significantly higher for DRV/r (76%) than LPV/r (63%)
(difference: 14%; 95% CI: 2, 25; P=.023). In patients
with lower baseline VL, virologic response for DRV/r
and LPV/r was 81% and 75%, respectively (difference:
5%; 95% CI: -2, 13; P=.174). Among patients with low
baseline CD4 cell count (<200 cells/mm3), response
rates were significantly higher for DRV/r (79%) than
LPV/r (65%) (difference: 14%; 95% CI: 4, 24; P=.009).
In patients with higher baseline CD4 cell count, 79%
of DRV/r patients and 75% of LPV/r patients achieved
VL <50 copies/mL (difference: 4%; 95% CI: -4, 12;
P=.345). Fewer DRV/r than LPV/r patients (4% vs 9%)
discontinued treatment due to adverse events. Fewer
DRV/r than LPV/r patients (4% vs. 11%) had grade
2-4 treatment-related diarrhea. Grade 2-4 treatmentrelated rash occurred infrequently (3% DRV/r vs 1%
LPV/r). DRV/r patients had smaller mean increases
in triglycerides and total cholesterol (0.1 and 0.6
mmol/L) than LPV/r patients (0.8 and 0.9 mmol/L);
levels remained below NCEP cut-offs for DRV/r for
both parameters.
Conclusions: In these treatment-naïve patients
at 96 weeks, a significantly higher proportion of
patients receiving DRV/r 800/100mg once-daily
achieved VL <50 copies/mL compared with LPV/r,
proving statistical non-inferiority and superiority
of DRV/r. DRV/r was associated with lower rates of
diarrhea and smaller mean increases in triglycerides
and total cholesterol.
Results: 343 and 346 patients were randomized
to DRV/r and LPV/r, respectively (N=689). Overall,
the mean baseline VL was 4.85 log10 copies/mL and
the median baseline CD4 count was 225 cells/mm3.
Significantly more patients on DRV/r (79%) than
LPV/r (71%) achieved VL <50 copies/mL at Week 96,
confirming DRV/r non-inferiority (difference: 8%;
57
Abstract 52
Etravirine (ETR; TMC125)
Demonstrates Favorable Efficacy
and Safety in the Phase III DUET
Trials Regardless of Geographic
Location
C Katlama1, PM Girard2, P Junod3, M Peeters4
L Leopold5, B Baeten4, and G De Smedt4
1Hôpital Pitié-Salpêtrière, Paris, France; 2 Hôpital SaintAntoine, Paris, France; 3 Clinique Médicale du Quartier
Latin, Montreal, Canada; 4 Tibotec BVBA, Mechelen,
Belgium; 5 Tibotec Inc., Yardley, PA, USA
BACKGROUND: Prevalence and incidence of HIV
varies considerably across regions. HIV clade, ethnic
influences on metabolism and comorbidities can vary
according to region and may affect a drug’s efficacy
and safety. It is therefore important to evaluate
antiretrovirals in different regions. Etravirine (ETR) is
a next-generation NNRTI which demonstrated potent,
durable activity against HIV-1 in the multinational,
cross-regional Phase III DUET trials over 48 weeks.
We present pooled DUET 48-week efficacy and safety
data according to geographic location.
percentage of patients in Europe (69% for ETR and
44% for placebo) and Latin America (62% and 43%)
achieved VL<50 copies/mL than patients in North
America (55% and 35%). Importantly, the added
benefit of ETR use versus placebo was similar across
regions. The percentage of patients achieving VL<50
and <400 copies/mL was significantly higher for ETR
versus placebo, irrespective of geographic location.
Change in CD4 cell count from baseline was greater
for ETR versus placebo in all regions. In general,
adverse events (AEs) were comparable across groups
and regions. However patients in North America
reported a higher incidence of grade 3/4 AEs in both
groups (40% each group).
CONCLUSIONS: In DUET, while slight differences
in efficacy and safety were observed across regions,
patients receiving ETR+BR achieved statistically
significantly higher virologic responses than those
receiving placebo+BR, irrespective of geographic
location. In addition, ETR was well tolerated, with
incidence and severity of AEs comparable to placebo,
regardless of location.
METHODS: Patients with documented NNRTI
resistance, ≥3 primary PI mutations and viral load
(VL)>5000 copies/mL were randomized 1:1 to
receive ETR 200mg or placebo, both twice-daily, with
a background regimen (BR) of darunavir/low-dose
ritonavir, investigator-selected NRTIs and optional
enfuvirtide. The primary efficacy endpoint was the
proportion of patients achieving VL<50 copies/mL.
Safety and tolerability were also assessed.
RESULTS: Patients were recruited from 185 centers
across North America (n=524), Latin America
(n=329), Australia (n=15), Europe (n=331) and
Thailand (n=4). 599 and 604 patients received
ETR+BR or placebo+BR, respectively. In general,
baseline demographics were comparable across
groups and locations, although a higher percentage
of males were recruited in North America. A higher
58
Parameter,%
Efficacy
VL<50 copies/mL
VL<400 copies/mL
Mean(SE) change in CD4 cell
count from baseline
Safety
Any AEs
Any Grade 3/4 AEs
Any SAEs
Discontinuations
Europe
ETR+BR Placebo+BR
(n=162)
(n=169)
Geographic Location*
Latin America
ETR +BR Placebo+BR
(n=162)
(n=167)
North America
ETR+BR
Placebo+BR
(n=266)
(n=258)
69‡
77‡
44
49
62§
75‡
43
54
55‡
66‡
35
41
105(7.5)
87(9.2)
121(10.8)
91(9.3)
79(6.3)
47(5.1)
96
29
20
6
96
33
23
5
95
25
20
6
97
31
22
4
97
40
20
9
95
40
25
8
Europe: France, Germany, Italy, Spain, Belgium, UK, Netherlands, Poland, Portugal; Latin America: Brazil, Argentina, Mexico, Panama,
Chile, Puerto Rico; North America: United States, Canada. *Number patients in Thailand and Australia was too low to allow separate
subgroup analyses; ‡p<0.0001;§p=0.0002.
Abstract 53
Pharmacokinetics and Short-term
Safety and Efficacy of Once-daily
Etravirine Without and With
Once-daily Darunavir/ritonavir
in Antiretroviral-naïve HIV-1
Infected Adults
J Lalezari1, E DeJesus2, O Osiyemi3, P Ruane4, R Ryan5,
B Polsonetti6, TN Kakuda5, and J Witek6
1 Quest Clinical Research, San Francisco, CA, USA;
2 Orlando Immunology Center, Orlando, FL, USA;
3 Triple O Medical Services Inc., West Palm Beach, FL,
USA; 4 Medical Practice of Peter Ruane, Los Angeles,
CA, USA; 5 Tibotec, Inc, Yardley, PA, USA; 6 Tibotec
Therapeutics, Bridgewater, NJ, USA; 6Yale-New Haven
Hospital, New Haven, CT, USA; 7Tibotec, Therapeutics,
Bridgewater, NJ,
etravirine plus tenofovir/emtricitabine without and
with darunavir/ritonavir in HIV-infected patients.
Methods: HIV-1-infected antiretroviral-naïve
adults without evidence of HBV/HCV-co-infection
or resistance to study drugs were eligible. Patients
received etravirine 400mg once-daily with tenofovir/
emtricitabine 300/200mg once-daily for 14 days,
added darunavir/ritonavir 800/100mg oncedaily for Days 15–28, and discontinued etravirine
for Days 29–42. Pharmacokinetic sampling was
performed over 24 hours on Day 14 for etravirine,
and Day 28 for etravirine, darunavir and ritonavir.
All doses were administered following a meal.
Pharmacokinetic parameters were determined using
a noncompartmental model with extravascular input
and evaluated by least squares mean (LSM) ratios
Background: Etravirine has a terminal elimination
half-life of 30–40 hours, and is a candidate for oncedaily dosing. In healthy volunteers, etravirine AUC
was similar, Cmax was 44% higher and Cmin was 25%
lower for once-daily versus twice-daily dosing. Oncedaily darunavir/ritonavir was shown to be effective
and well-tolerated in antiretroviral-naïve patients.
This multicenter, open-label Phase IIa trial evaluates
pharmacokinetic and short-term safety and efficacy of
59
with 90% confidence intervals (CI). Fasting labs were
evaluated in each phase.
Results: Twenty-three patients (20 men) enrolled:
9 black, 9 white and 5 Hispanic; mean age 35.9
years; mean baseline viral load (VL) 4.2 log10 copies/
mL; median baseline CD4 403 cells/mm3. LSM and
90% CIs for etravirine with and without darunavir/
ritonavir demonstrated equivalence. Mean (SD)
AUC24h, Cmax and Cmin for etravirine without and with
darunavir/ritonavir were 10410 (4186) and 10720
(5459) ng*h/mL, 790 (287) and 801 (327) ng/mL,
and 233 (130) and 236 (168) ng/mL, respectively.
Mean (SD) AUC24h, Cmax and Cmin for darunavir were
76130 (22080) ng*h/mL, 7008 (1514) ng/mL, and
1049 (616) ng/mL, respectively. Mean (SD) AUC24h,
Cmax and Cmin for ritonavir were 4128 (1854) ng*h/mL,
465 (231) ng/mL, and 27 (21) ng/mL, respectively.
Darunavir pharmacokinetics were slightly higher and
ritonavir pharmacokinetics slightly lower relative to
historic controls (ARTEMIS week 4 PK substudy).
Mean VL decline was 1.7 log10 copies/mL at Day 14
(n=21) and 2.0 log10 copies/mL at Day 42 (n=20).
Median CD4 increase was 56 cells/mm3 (Day 42).
Most common treatment-emergent AEs were nausea
(n=4), headache (n=3), rash (n=3), and flatulence
(n=2). No serious or grade 3/4 AEs were reported; no
AEs led to discontinuation. Median (range) changes
from baseline were 11 (-64, 58), -1 (-30, 8), 1.5 (-39,
49), and 32 (-88, 166) mg/dL for total cholesterol,
HDL, LDL, and triglycerides, respectively, over 42
days.
Conclusions: Addition of once-daily darunavir/
ritonavir to once-daily etravirine had no significant
impact on etravirine pharmacokinetics, and exposure
to etravirine was adequate with and without
darunavir/ritonavir. The impact on metabolic
parameters was small when etravirine was given with
or without darunavir/ritonavir. Pharmacokinetic data
and short-term safety and efficacy support further
clinical investigation of etravirine 400mg once-daily
in HIV-1-infected patients.
60
Abstract 54
Activation of Different Cell
Death Pathways in Patients on
Antiretroviral Therapy with
Long-term Viral Suppression
but Unfavorable Immunologic
Response
E Negredo1, M Massanella2, J Puig1, N Pérez-Álvarez1,3,
B Clotet1,2, and J Blanco2
1 Lluita contra la SIDA Foundation, Germans Trias i
Pujol University Hospital, Barcelona, Spain; 2 Irsicaixa
Foundation, Germans Trias i Pujol University Hospital,
Barcelona, Spain; 3 Statistics and Operations Research
Department, Technical University of Catalonia, Barcelona,
Spain
Background: Apoptosis and other mechanisms of
cell death play a determinant role in CD4+ cell loss
in HIV-infected patients. Highly active antiretroviral
treatment (HAART), by reducing viral replication,
induces a decline in the level of apoptosis that
contributes to immune recovery. However, some
patients present a discordant response to treatment,
maintaining or reducing CD4+ cell counts despite
control of viral replication under detectable levels.
Methods: A cross-sectional, descriptive, comparative study was performed to evaluate the role
of apoptosis and other cell death pathways in CD4
T cell recovery. We included 168 patients on HAART
with undetectable viral load (VL< 50 copies/mL) for
more than 2 years; 50 of them were considered as
“Discordant” (unfavorable immunologic response:
increase <100 CD4+ cells/mm³ with respect to baseline
or CD4+<350 cells/mm³) and 118 as “Concordant”
(favourable immunologic response). Activation
markers were measured in fresh blood, while cell
death was analyzed in PBMC cultured for 0, 1 or 4
days in the absence or the presence of the pancaspase
inhibitor ZVAD-fmk. Multicolor flow cytometry was
used combining antibodies, the vital dye PI and the
mitochondrial probe DIOC6.
Results: No baseline differences between discordant and concordant patients were observed regarding
gender, mean age, mean time with HIV infection,
current antiretroviral therapy (42.9% on PI; 57.1% on
NNRTI) and percentage of HCV co-infection (33.9%).
Levels of total death (defined as DIOC low cells) in
CD4+ cells were statistically higher in discordant
than in concordant patients at day 0 (p<0.001), day 1
(p<0.001) and day 4 (p<0.001). Significant differences
were also found in a detailed analysis of cell death
pathways. Necrosis (defined as DIOC low, PI+ cells)
and global apoptosis (defined as DIOC low PI- cells)
were higher (p<0.001) in discordant patients. Similarly
increased levels of intrinsic (p<0.001) and extrinsic
apoptosis (p<0.001), determined by the mitochondrial
protection induced by ZVAD at day 1, were also higher
in discordant patients. No significant differences were
observed when we measured the same parameters in
CD8+ cells except levels of necrosis at day 1 that were
higher in discordant subjects (p=0.005). Consistently
activation markers (CD95 or HLA-DR) showed more
marked differences in the CD4 than in the CD8 T cell
compartment.
Conclusion: The higher levels of activation and
CD4+ T cell death in discordant patients suggests a
key role of the different mechanisms of cell death,
including necrosis and apoptosis, in immune
recuperation. Therapeutic interventions aimed to
reduce cell death (by reducing toxicity or residual viral
replication) may be required in discordant patients.
Abstract 55
Safety and Tolerability of the
Lopinavir/ritonavir (LPV/r) Tablet
in Comparison to other Protease
Inhibitors (PIs): The SAPIKAT
trial
UF Bredeek1, B Williams1, R Rode2, T Sparrow2, and
R Stryker2
1 Special Immunology Associates, Tucson, AZ, USA;
2 Abbott Laboratories, Chicago, IL, USA
Background: LPV/r tablet has improved
characteristics compared to soft gel capsules (SGC).
Side effects and tolerability of LPV/r tablets compared
with other PIs have not been fully evaluated.
Methods: Open-label, prospective evaluation
of the tolerability and Quality of Life (QOL) of
LPV/r tablets dosed once daily (QD) in virologically
suppressed subjects switching the PI component of
their antiretroviral therapy (ART). Patient-reported
outcomes were evaluated at entry and 12 weeks
using the Medical Outcomes Study-HIV (MOSHIV) Health Survey, the Center for Epidemiologic
Studies–Depression (CES-D) questionnaire and a
modification of the ACTG Symptoms Distress Module
(SDM). CD4+, HIV-1 viral load (VL), fasting lipids,
and chemistries were assessed at entry and 24 weeks.
Analysis was done using paired t-tests and Wilcoxon
signed rank tests.
Results: A total of 60 subjects on atazanavir/
ritonavir (N=33), saquinavir/ritonavir (N=3),
nelfinavir (N=2), fosamprenavir/ritonavir (N=11), or
LPV/r SGC (N=11) containing regimens switched to
LPV/r tablets QD. Reasons for switch were Grade 3-4
total bilirubin (N=33), desire for QD dosing (N=16),
or withdrawal of the LPV/r SGC formulation (N=11).
7 subjects withdrew prior to week 24 for intolerance;
4 subjects were lost to follow-up. At week 12 or
premature discontinuation, no statistically significant
changes were observed in MOS-HIV domain scores or
CES-D (P ≥ 0.188). However, mean symptom scores
61
were increased for diarrhea (0.6±1.55; P=0.010),
bloating (0.5±1.53; P=0.011) and dizziness (0.4±20;
P=0.013). Lack of a refrigeration requirement
positively impacted QOL in 36% of subjects. 21% felt
QOL was improved by lack of food requirements. 60%
preferred LPV/r tablet, 25% preferred their previous
PI, and 15% had equal preference. Reasons for
premature discontinuations were not collected as part
of the study. Bilirubin normalized in those subjects
with baseline elevations. No significant changes from
baseline to week 24 were observed for VL and CD4
count. Mean increases in total cholesterol (14.5±40.00
mg/dL; P=0.014), LDL (9.0±26.76 mg/dL; P=0.034)
and triglycerides (99.4±370.98 mg/dL; P=0.067) were
seen; however, HDL was not significantly changed. 2
patients were started on statin therapy during the
study.
with TDF/FTC. The TITAN trial (TMC114-C214)
evaluated LPV/r versus DRV/r 600/100 mg BID in
treatment-experienced patients with HIV-1 RNA
>1000 copies/mL, in combination with an optimized
background regimen consisting of nucleoside +/- nonnucleoside reverse transcriptase inhibitors.
Conclusions: The change of the PI to LPV/r in
otherwise unchanged ART allowed direct measure
of LPV/r tablet tolerability without confounding
therapy. HIV-1 suppression was maintained and
despite an early increase in gastrointestinal related
symptom scores, LPV/r was generally well tolerated,
and preferred by most patients.
RESULTS: The overall results from ARTEMIS and
TITAN at Week 96 were as follows:
Abstract 56
TITAN – Week 96, HIV RNA <400
ITT 66.4%
57.6%
8.8%
ITT non-VF
censored
88.4%
76.1%
12.4%
Analysis of Virologic Endpoints
Versus Standard Intent to Treat, in
ARTEMIS and TITAN Trials
A Hill1, L Chen2, F Tomaka2, H Huong3, and R DeMasi2
1 Liverpool University, Liverpool, UK and Tibotec,
Mechelen, Belgium; 2 Tibotec R&D, Yardley, USA;
3 Janssen-Ortho, Toronto, Canada
BACKGROUND: Phase 3 trials of new antiretrovirals
are normally analyzed using Intent to Treat (ITT)
methods, with any patient discontinuing randomized
treatment counted as a failure. The ARTEMIS trial
(TMC114-C211)
evaluated
lopinavir/ritonavir
(LPV/r) versus darunavir/ritonavir (DRV/r) 800/100
mg QD in treatment naïve patients, in combination
62
METHODS: In the ARTEMIS and TITAN trials, the
primary endpoint of “virologic failure” was HIV RNA
>50 copies/mL (ARTEMIS) and >400 copies/mL
(TITAN), as well as prior discontinuation for adverse
events or other reasons. In this analysis, ITT analyses
were repeated, excluding any discontinuation for
non-virologic reasons (ITT non-VF censored). A
MEDLINE search of other clinical trials was conducted
to estimate the proportion of virologic endpoints in
Intent to Treat analyses of other trials.
Trial
DRV/r
LPV/r
Difference
ARTEMIS – Week 96, HIV RNA <50
ITT
79.0%
70.8%
8.2%
ITT non-VF
censored
92.8%
87.2%
5.6%
p value
<0.05
<0.05
<0.05
<0.05
In the ITT analyses of ARTEMIS and TITAN, 57/173
(33%) and 103/226 (46%) of the primary endpoints at
Week 96, respectively, were virologic failures. Of the
57 virological endpoints in ARTEMIS, 13 (21%) were
patients whose HIV RNA was never suppressed below
50 copies/mL (4 DRV/r, 9 LPV/r), while 44 (79%)
were rebounds in HIV RNA after initial suppression
below 50 copies/mL (17 DRV/r, 27 LPV/r). Of the
103 endpoints in TITAN, 68 (66%) were patients
whose HIV RNA was never suppressed below 400
copies/mL (22 DRV/r, 42 LPV/r) while 39 (34%) were
rebounds in HIV RNA after initial suppression below
400 copies/mL (13 DRV/r, 26 LPV/r). The MEDLINE
search of 17 trials (n=8582) showed the percentage of
virologic endpoints in ITT analyses was 25% for trials
of naïve patients and 74% for trials of experienced
patients.
CONCLUSIONS: In ARTEMIS and TITAN, there
was a statistically significant increase in efficacy
for DRV/r versus LPV/r, both in the primary ITT
analysis, and when only observed virologic endpoints
were included. If discontinuation rates for adverse
events or other reasons are high in HIV clinical trials,
additional analyses including only virologic endpoints
are needed to confirm the efficacy conclusions.
Abstract 57
Improvement of the
Transglycosylation Reaction for
the Synthesis of β-D-3’-Azido2’,3’-Dideoxypurine Nucleoside
Analogs by Conventional and
Microwave Assisted Heating
SJ Coats1, H-W Zhang2, L Bondada2, M Detorio2,
J Mellors3, and RF Schinazi2
1 RFS Pharma LLC, Tucker, GA, USA; 2 Emory Univ./VA
Med. Ctr. Atlanta, GA USA; 3 Univ. of Pittsburgh/VA Med.
Ctr., Pittsburgh, PA, USA
synthetic approach starting with readily available
5’-protected AZT and its corresponding U-analog,
AZU. Transglycosylation reaction conditions were
modified using microwave-assisted synthesis and
coupled with an analytical HPLC-MS method that
allowed for rapid determination of yield of the desired
beta isomer.
Results: Treatment of 5’-protected AZT or AZU
with an appropriate purine in the presence of
Lewis acid produced a mixture of α and β isomers.
Removal of the 5’-protecting group and subsequent
purification provided the pure β-3’-azidopurine
nucleosides in reasonable yield (30-40%). Reaction
time, temperature, solvent, Lewis acid, and various
additives were rapidly optimized using microwaveassisted synthesis. A series of novel 3’-azido-2’,3dideoxypurine analogs have been synthesized using
this new method that have potent anti HIV-1 in
human peripheral blood mononuclear (PBM) cells
and low cytotoxicity in PBM, CEM and Vero cells.
Conclusions: The transglycosylation reaction with
conventional heating or microwave assisted synthesis
proved to be an efficient means of synthesizing new,
structurally diverse 3’-azido-2’,3’-dideoxypurine
analogs, several of which have potent and selective
anti-HIV activity and are undergoing further
preclinical evaluation.
Background: Recently we discovered that
β-D-3’-azido-2’,3’-dideoxyguanosine has potent
anti-HIV activity and a more favorable resistance
profile compared to AZT. In contrast to 3’-azido
pyrimidine nucleosides, 3’-azido-purine nucleosides
are challenging to synthesize. Transglycosylation of
3’-azido pyrimidine nucleosides with purine bases
offers an improved and facile synthetic approach,
but yields of the desired beta isomer are low (4-27%).
We sought to improve beta isomer yield from the
transglycosylation approach.
Methods: Traditionally, 3’-azidopurine analogs
are prepared by low-yielding multistep nucleoside
modification approaches. We investigated a simpler
63
Abstract 58
The Phtalocyanine Prototype
Derivative Alcian Blue: The First
Synthetic Agent with Selective
Anti-human Immunodeficiency
Virus Activity Due to Its Lectinlike Properties
KO François, C Pannecouque, D Schols, and J Balzarini
Laboratory of Virology and Chemotherapy, Rega Institute
for Medical Research, Leuven, Belgium
Background: The envelope of HIV consists of two
subunits: the surface gp120, and the transmembrane
gp41. Both units are highly glycosylated, which is
essential for the virus to escape immune surveillance.
Carbohydrate binding agents (CBAs), such as the
plant lectins Hippeastrum hybrid agglutinin (HHA)
and Urtica dioica agglutinin (UDA) bind to the glycans
that are present on the envelope of HIV and inhibit the
viral entry process. Recently, pradimicin A (PRM-A),
an antifungal nonpeptidic antibiotic was described to
possess lectin-like properties, to bind to HIV gp120
and to be able to efficiently prevent HIV infection.
Another nonpeptidic compound, Alcian Blue (AB), a
phtalocyanine derivative, also has antiviral activity
against HIV. We investigated further its antiviral and
lectin-like properties.
Methods: A time-of-addition experiment was
performed to determine the target of AB in the viral
life cycle. An AB-resistant virus strain was selected
in CEM T-cell cultures, under dose-escalating AB
concentrations. The entire envelope region was
sequenced after DNA extraction of the proviral DNA.
Cross-resistance against other CBAs was determined
in antiretroviral assays, based on syncytia formation.
The antiviral activity was determined against
several DNA and RNA viruses, and its ability to
inhibit syncytium formation was observed using
a co-cultivation assay between Sup-T1 cells and
persistently infected Hut-78/HIV cells. Using a virusbinding-assay in the presence of mannan, the lectinlike properties of AB were investigated.
64
Results: Based on time-of-addition experiments, AB
was determined to be an entry inhibitor. Its antiviral
acitivity against HIV-1 in CEM T-cells was 4.8 ± 2.6
µg/ml, while the AB-resistant virus strain was about
10-fold more resistant to AB. AB was able to inhibit
syncytium formation between persistently HIV-1infected Hut-78/HIV cells and Sup-T1 cells with an
EC50 of 8.0 ± 2.8 µg/ml. AB-resistant virus, selected
under increasing concentrations of AB, showed up to
4 mutations in N-glycosylation motifs (NXS/T, with
X any amino acid, except P) of gp120, resulting in the
deletion of 4 N-glycans. A similar mutational pattern
was also observed in previous analogous experiments
with the CBAs HHA, UDA, 2G12, cyanovirin and
PRM-A. Virus-binding assays in the presence of
mannan clearly indicated that AB, like the CBAs HHA
and PRM-A, has a preference for high-mannose type
sugars.
Conclusions: Here we provide evidence for the
antiviral and lectin-like properties of the nonpeptidic
compound Alcian Blue. Its mode of action is
comparable with the mode of action of the CBAs
HHA, UDA and PRM-A. AB may be important as
lead compound in the development of novel antiviral
drugs targeting the envelope glycoproteins of HIV.
Abstract 59
Long-time Virologic Efficacy of
Boosted Double Protease Inhibitor
Therapy
H Knechten, C Höhn, J Vachta, and P Braun
PZB Aachen, Germany
Background: Double-protease inhibitor regimens
have been shown to be a therapeutic option for
patients with treatment failure or adverse events. In
2005 we presented at the IAS-conference following
retrospective analysis “24 weeks follow-up with ATV
and SQV/r in protease inhibitor (PI) experienced
HIV1-infected patients”. The aim of this retrospective
evaluation is to examine the long-time efficacy of such
double PI regimens.
Methods: 144 weeks follow up of 12 PI-experienced
patients starting with boosted ATV/SQV (IAS, Rio
de Janeiro, 2005; Abstract: WePe12.9C11). Patients
had a median HIV-RNA of 206 copies/ml and mean
CD4 counts of 569 ± 390 cells/µl. The average number
of therapies was 3.8 with a mean duration of 70.8
months. Furthermore we analysed virological and
immunological parameter of 7 patients starting later
on with a boosted double PI regimen (Lopinavir/
Saquinavir n=4; or Atazanavir/Saquinavir n= 3) (N=1
with 3TC). Therapy success was defined as a viral load
≤ 40 copies/ml.
Results: 11 patients who started with boosted ATV/
SQV reached week 144. 1 patient was lost to follow up.
4 had an undetectable viral load, 1 was non-adherent,
2 changed therapy due to side effects (ikterus and
buffalo hump) and 2 due to virological failure.
6 of 7 patients of the second group reached week
144 yet. 6 Patients had a viral load below the limit
of detection, increasing CD4 counts and the regimens
were well tolerated. 1 patient was non-adherent.
Conclusion: Although double PI Regimens are
no longer standard of care for patients with limited
therapy options these regimens seem to be effective for
a high a number of patients in this retrospective longtime evaluation. Nevertheless further exploration of
these regimens with regard to metabolic side effects
and quality of life is warranted, especially in the era of
new drug classes.
Abstract 60
Etravirine Demonstrates a
Favorable Safety and Tolerability
Profile at Week 48 in the Pooled
DUET Trials Irrespective of
Gender, Age, Ethnicity and Weight
JV Madruga1, EG Kallas2, J Sampson3, F Mazzotta4,
M Peeters5, K Janssen5, E Lefebvre6, and B Woodfall5
1 Centro de Referência e Treinamento DST/AIDS, SãoPaulo, Brazil; 2 Federal University of São Paulo, São Paulo,
Brazil; 3 Research & Education Group, Portland, Oregon,
US; 4 Hosp. S M Annunziata, Firenze, Italy; 5 Tibotec
BVBA, Mechelen, Belgium; 6 Tibotec, Amsterdam,
the Netherlands
BACKGROUND:
Etravirine
(ETR;
TMC125)
demonstrated favorable safety and tolerability in
treatment-experienced, HIV-1-infected patients in
the phase III DUET trials over 48 weeks. We present
a sub analysis of safety data from pooled 48-week
DUET subgroup analyses.
METHODS: Patients were randomized 1:1 to ETR
(200mg bid) or placebo, both in combination with
a background regimen (BR) of darunavir/low-dose
ritonavir, investigator-selected NRTIs and optional
enfuvirtide. Pre-specified subgroup analyses of
the effect of gender, age, ethnicity and weight on
incidence/severity of adverse events (AEs; including
laboratory AEs) were conducted on pooled 48-week
data.
RESULTS: 599 and 604 patients received ETR and
placebo, respectively. Baseline characteristics were
similar across treatment groups. The incidence of any
AE and grade 3 or 4 AEs were generally comparable
across subgroups and between treatments. For
Hispanic patients, however, the incidence of grade 3
or 4 AEs, serious AEs (SAEs) and discontinuations due
to AEs with ETR + BR was higher than with placebo
+ BR. Caucasian patients receiving ETR reported the
lowest incidence of SAEs. Patients aged >55 years
receiving placebo experienced a higher incidence
65
of SAEs compared with other age groups. A higher
incidence of rash occurred in the ETR group in women
(30%) than in men (18%). However, no differences
in severity of rash or rate of discontinuation were
observed in men versus women. No clinically relevant
differences were observed for other AEs.
CONCLUSIONS: In this 48-week subgroup analysis,
the only clinically relevant difference in AEs was
increased rash in women versus men. Findings in the
small number of Hispanic patients in this analysis
require further exploration in larger datasets.
Overall ETR + BR demonstrated favorable safety
and tolerability versus placebo + BR, irrespective of
gender, age, ethnicity and weight.
Any AE (%)
Subgroup
(N ETR, placebo)
Gender
Male (539, 535)
Female (60, 69)
Ethnicity
Caucasian (373, 376)
Black (70, 70)
Hispanic (60, 66)
Other* (29, 27)
Age, years
18–40 (111, 116)
>40–55 (412, 399)
>55 (76, 89)
Weight, kg‡
≤62.8 (149, 151)
>62.8–72.0 (151, 170)
>72.0–80.3 (137, 145)
>80.3 (162, 138)
Grade 3/4 AEs (%)
SAEs (%)
ETR
(N=599)
Placebo
(N=604)
ETR
(N=599)
Placebo
(N=604)
ETR
(N=599)
Placebo
(N=604)
95.9
96.7
96.3
94.2
33.6
30.0
35.0
34.8
20.0
16.7
24.3
15.9
96.2
94.3
95.0
96.6
95.5
95.7
97.0
96.3
31.4
37.1
41.7
24.1
35.4
44.3
22.7
40.7
16.6
24.3
28.3
17.2
23.4
25.7
16.7
33.3
96.4
95.6
97.4
98.3
94.7
98.9
33.3
33.5
31.6
35.3
34.3
37.1
22.5
18.7
21.0
21.6
21.8
32.6
97.3
96.7
97.1
93.2
95.4
97.6
95.9
94.9
36.2
34.4
37.2
25.9
38.4
34.7
31.0
35.5
25.5
19.2
21.9
13.0
26.5
23.5
19.3
23.9
*Including Asian patients; ‡Categories were done by weight quartiles.
66
Abstract 61
Adherence to Darunavir/ritonavir
(DRV/r) and Lopinavir/r (LPV/r)
in Treatment-naïve HIV Patients
in ARTEMIS
TM Mills1, P Chetchotisakd2, R DeMasi3, L Chen3,
E Smets4, V Sekar3, S Spinosa-Guzman4, and E Lefebvre5
1 Los Angeles, CA, USA; 2 Khon Kaen University, Khon
Kaen, Thailand; 3 Tibotec Inc, Yardley, PA, USA; 4 Tibotec
BVBA, Mechelen, Belgium; 5 Tibotec, Amsterdam,
the Netherlands
Background: ARTEMIS is a controlled Phase III
trial examining efficacy and safety of DRV/r qd vs
LPV/r in treatment-naïve HIV patients. This analysis
examined patient-reported adherence and its
association with other data collected to week 48.
Methods: The M-MASRI questionnaire assessed
self-rated adherence by percentage of doses of DRV/r
and LPV/r taken during the past 30 days. Rates were
transformed into a binary variable (adherent [>95%]
and non-adherent [≤95%]). At week 48, confirmed
virologic responses and AEs were tabulated over time
by adherence.
Results: Overall adherence was high; however, 48
(15%) of DRV/r patients and 58 (18%) LPV/r patients
had week-4 to week-48 mean adherence ≤95%.
Response rates (<50 copies/mL, ITT-TLOVR) were
higher in the adherent vs non-adherent groups (OR:
0.5 (0.3, 0.8)), with a smaller difference in response
for DRV/r (DRV/r: 87% vs 79%; LPV/r: 85% vs 69%).
Non-adherent patients reported more AEs. At week
12, 28% of DRV/r and 23% of LPV/r non-adherent
patients reported GI AEs, compared with 7% and 13%,
respectively of adherent patients. Reported GI events
dropped steeply after week 12, making it difficult
to assess impact on adherence after this time. Total
distress scores from a list of 39 symptoms were higher
in non-adherent versus adherent patients in both
arms. Adherence to both DRV/r and LPV/r differed
by race (Black patients, DRV/r: 23% non-adherent;
LPV/r: 38% non-adherent; non-Blacks, 12% and 13%
non-adherent, respectively). Self-reported missed
doses due to symptoms (P<0.01), and plasma drug
concentrations (P<0.01) correlated with adherence,
suggesting validity of this assessment.
Conclusion: Non-adherence to LPV/r compromised
virologic response more than non-adherence to DRV/r.
Non-adherence was correlated with AEs (particularly
GI), and symptoms or symptom-related perceived
distress associated with ARV therapy, suggesting
factors other than convenience are also significant
drivers of adherence.
Abstract 62
Irreversible Pepsin Fraction
(IPF) Displays Significant
Antiretroviral Activity via Specific
Novel Cytokine Stimulation In
Vitro Investigation of Activity on
Human Lymphocytes
H Zhabilov1, M Selbovitz, D Miller2, and J Gibbs
1 Immunotech Laboratories, CA, USA; 2 AIDS Institute,
NY, USA
Background: Resistance to all commercially
available antiretroviral (ARV) agents within all
classes has been reported. The occurrence of multiclass resistance remains high, with 20% of infected
individuals developing resistance to two or more
classes within six years of initiating treatment, and
10% of newly diagnosed infections already resistant
to at least one class in the U.S. Multi-class resistance
is even more prevalent in disenfranchised patient
populations, whose rates of successful adherence to
even the most simplified regimens available remains
prohibitively low. Other mechanisms to treat HIV
infection are sorely needed. IPF, like other natural
autoantibody based fractionated proteins, has an
affinity to pathogenic binding and simultaneously
produces effects of immune homeostasis in the
67
presence of replacativly competent HIV. IPF has
shown significant antiretroviral activity via immune
stimulatory pathways in vitro, notably helper T1 cells
elaborate cytokines INFy, IL-2. These cells selectively
promote cell-mediated immune responses that are
disadvantageous to viral replication with selection
for the pathogenesis of resistant profiles of minority
subspecies.
Methods: Flow cytometric analysis of these cells
was conducted using DC monoclonal antibodies and
Annexin-V. A Biacore assay system that measures
changes in the surface mass concentration was used
to determine interactions between IPF molecules and
CD4+ cells. Changes were expressed in resonance
units (RU), with one RU representing a change in
concentration of 1 pg/ mm. T cells were purified from
peripheral blood mononuclear (PBMC) cells using
anti-body coated magnetic beads.
Results: Laboratory analysis indicates that IPF is
able to mediate maturation of dendrites cells in vitro,
as determined by up-regulation of MHC class-ll, CD86
and CD83 molecules, regulate pro-inflammatory
cytokines IL-12 and INFy, and enhanced T-cells
stimulatory capacity. Observable characteristics
include modulation of complement activation,
saturation of Fc receptors on macrophages, and
suppression of various inflammatory mediators,
including cytokines and chemokines.
IPF
demonstrated increased synthesis of Th-1 cells. IPF
displayed spontaneous binding with gp41 when
prepared for gel electrophoresis, and subsequent
fusion inhibition of HIV with CD4+ cells and increased
gp41 and gp120 antigenic activity. Virus-specific
CD8 cells were stimulated. Flow cytometric analysis
revealed apoptosis in CD4+ cells and stimulation of
virus-specific CD8 cells. Conclusions: IPF appears to modulate helper T1
cells’ expression of elaborate cytokines INFy, IL-2,
which selectively promote cell-mediated immune
response and subsequently stimulate cytotoxic
lymphocytes. These lymphocytes have a prominent
role in the host’s immunologic response to HIV
infection. Proteins encoded by these pathogens enter
68
the endogenous pathway for antigen presentation
and are expressed on the surface of the infected cell
as a complex with class l MHC- proteins. IPF appears
to present a novel mechanism to reduce viral burden
and stimulate innate immune responses to the virus
for patients with significant antiretroviral resistance.
ABStract 63
Successful Use of Dual Therapy
with Etravirine and Raltegravir in
Patients with HIV Infection
G Pierone1, JA Mieras1, DE Bulgin2, AJ Balconis2, and
CD Kantor1
1 Treasure Coast Infectious Disease Consultants, FL, USA;
2 AIDS Research & Treatment Center of the Treasure
Coast, FL, USA
Background: New classes of antiretroviral agents
and advancements in existing medication classes
have greatly expanded the strategic options for the
selection of antiretroviral cocktails. Some patients
have side effects and or viral resistance to both
nucleoside reverse transcriptase inhibitors (NRTIs)
and protease inhibitors (PIs). For these patients,
a NRTI-sparing and PI-sparing regimen might be
useful. Since etravirine and raltegravir have become
available, we have used dual therapy with this
combination in patients with resistance and or side
effects from PIs and NRTIs.
Methods: We reviewed the medical records of
all patients in our clinic who had been prescribed
etravirine and raltegravir as dual therapy. Chart
reviews included collection of data that included
previous antiretroviral regimens, resistance assays,
CD4+ lymphocyte counts and HIV RNA levels, lipid
profiles, and the reasons for the selection of this
regimen.
Results: We identified 20 patients who were
prescribed dual therapy with etravirine and raltegravir
and had follow up viral load and CD4+ lymphocyte
count testing. Antiretroviral medication intolerance
was the primary reason for change in 17 patients and
multi-drug resistant virus in the other three patients.
Eight of these 20 patients had undetectable viral load
at time they started this regimen.
Two patients stopped therapy because of side effects.
Of the remaining 18 patients, two experienced an
early rebound in viral load on this regimen and had
treatment intensified. In retrospect, these two
patients had diminished etravirine activity based
on archived resistance testing and prior treatment
history.
Of the remaining 16 patients, two had detectable
viremia with HIV RNA readings of 71 and 128 copies/
mL respectively and continue dual therapy. The
remaining 14 patients have viral load <48 copies/
mL at a mean follow up of 16.6 weeks (range 4 to 60
weeks).
Conclusion: These retrospective short-term results
suggest that the use of dual therapy with etravirine
and raltegravir may be useful in the management of
HIV infection. This regimen deserves further study
in patients with NRTI or PI associated side effects
and/or viral resistance.
Abstract 64
HIV-1 Co-receptor Use in Heavily
Treatment-experienced Spanish
Patients
JR Arribas1, S Moreno2, A Rivero3, F RodriguezArrondo4, M Leal5, and R Sanchez-de la Rosa6
patients infected with only CCR5-tropic (R5) HIV1 detectable. Information on the epidemiology of
HIV-1 co-receptor use has been provided by clinical
trials of entry inhibitors (TORO [Whitcomb et al.
CROI 2007], MOTIVATE [Coakley et al. Targeting
HIV Entry Workshop 2006], and ACTG 5211 [Wilkin
et al. Clin Infect Dis 2007]) and a limited number
of observational studies. However, little is known
about the different patterns of tropism distribution
in specific countries. The objective of our study was
to evaluate the distribution of R5, dual/mixed-tropic
(D/M), and CXCR4-tropic (X4) HIV-1 in heavily
treatment-experienced patients in Spain.
Methods: All treatment-experienced Spanish
patients who participated in the maraviroc expanded
access program (A4001050), the named patient
program in Spain (July 2007 to January 2008), or the
ALLEGRO Study (A4001077; January to June 2008)
and who were screened for HIV tropism were included.
Tropism was determined using the original/standard
Trofile™ assay (Monogram Biosciences, South San
Francisco, CA, USA).
Results: Co-receptor use was evaluated for 865
treatment-experienced patients. In 125 cases (14%),
tropism results were non-determinable or nonreportable owing to various reasons, including one
sample found to be HIV-2. Of the remaining samples,
491 (66%) had an R5 tropism result, 23 (3%) were X4,
and 226 (31%) had a D/M tropism result.
Conclusions: The distribution of HIV-1 tropism
in heavily treatment-experienced patients in Spain
was similar to that reported for heavily treatmentexperienced patients in other regions where subtype
B predominates.
1 Hosp. Universitario La Paz, Madrid, Spain; 2 Hosp.
Universitario Ramón y Cajal, Madrid, Spain; 3 Hosp.
Universitario Reina Sofía, Córdoba, Spain; 4 Hosp. de
Donostia, Donostia, Spain; 5 Hosp. Universitario Virgen
del Rocío, Seville, Spain; 6 Pfizer Medical Unit, Madrid,
Spain
Background: Maraviroc (MVC) has been
approved for use in treatment-experienced adult
69
Abstract 65
Cost-effectiveness of Maraviroc
plus Optimized Background
Therapy in Treatment-experienced
Patients with R5 HIV-1 in Spain
S Moreno1, JM Llibre2, I Lekander3, B Martí4,
R Sánchez-de la Rosa4, and MA Casado5
1 Hospital Ramón y Cajal, Madrid, Spain; 2 Fundació
Lluita contra el SIDA, Hospital Germans Trial y Pujol,
Barcelona, Spain; 3 i3 Innovus, Stockholm, Sweden;
4 Pfizer Medical Unit, Madrid, Spain;
5 Pharmacoeconomics & Outcomes Research Iberia,
Madrid, Spain
Background: Maraviroc (MVC) is a first-inclass oral CCR5 antagonist, which prevents CCR5tropic (R5) HIV-1 from entering CD4+ cells. Phase
3 pivotal studies (MOTIVATE 1 & 2) of MVC 300mg
administered twice daily (BID) added to optimized
background therapy (OBT) in viremic, treatmentexperienced patients with CCR5-tropic (R5) HIV1 showed a clinically and statistically significant
reduction in viral load and increase in CD4+ cell
count compared to placebo (PBO) plus OBT at 48
weeks. MVC was well tolerated, resulting in a low
rate of discontinuation due to adverse events (AEs).
The objective of this study was to evaluate the costeffectiveness in the Spanish setting of MVC + OBT
vs PBO + OBT in a treatment-experienced patient
population similar to that recruited to the MOTIVATE
studies.
(ARV) regimen costs were derived from local official
sources. Non-ARV drug costs were obtained from
published literature and a national cost database. All
costs were expressed in 2007 euros (€). The annual
discount rate for both costs and effects was set to 3.0%.
The main outcomes were cost per life years gained
(LYG) and cost per quality-adjusted life years (QALY)
gained. To assess the uncertainty of the results, oneway sensitivity analyses and a probabilistic sensitivity
analysis (PSA) were performed.
Results: The results of the economic analysis showed
that adding MVC to OBT increases LYG by 0.952 years
and QALY by 0.909. Total cost were €291,663 for
maraviroc plus OBT and €268,012for OBT alone with
an incremental cost of €23,651. The resulting cost per
LYG was €24,852 and the cost per QALY gained was
€26,026. The model seemed robust for variation in
key parameters, ranging from €-3,500 (cost saving)
to €35,000 per QALY in the deterministic sensitivity
analyses. The results from the PSA indicate that the
probability of the cost per QALY falling below €30,000
is 95%.
Conclusions: Based on the superior clinical efficacy
results from the combined analysis of MOTIVATE
1 & 2 trials, our analysis indicates that maraviroc
300mg BID in combination with OBT is a clinically
valuable and cost-effective option for the treatment
of ARV-experienced patients infected with R5 HIV-1
in Spain.
Methods: A lifetime deterministic cohort model
from the hospital perspective was developed based
on combined data from MOTIVATE 1 & 2. In the base
case, treatment duration reflects the clinical trial
follow-up—ie, a lifetime effect of 1 year’s treatment
is assessed. Clinical data, cohort characteristics,
probability of treatment success, rate of CD4+ cell
increase, and the link to disease states and probability
of AEs (both opportunistic infections and drug
associated) were taken from the trials and published
literature, as appropriate. Other input parameters
were taken from published sources. Antiretroviral
70
Abstract 66
Once Daily Darunavir/ritonavir:
A Single Centre Cohort Experience
C Scott, A Teague, M Bower, B Gazzard, M Nelson
Chelsea & Westminster Hospital NHS Foundation Trust,
London, UK
BACKGROUND: Darunavir (DRV) is a novel nonpeptidic protease inhibitor (PI) with activity against
wild type and protease inhibitor resistant HIV-1 when
boosted with low dose ritonavir. We describe our
experience of using once daily darunavir/ritonavir
(900/100mg) in both treatment naïve and treatment
experienced patients with no baseline darunavir
resistance within the Chelsea & Westminster Hospital
cohort.
METHODS: This prospective observational study
followed a cohort of patients who received DRV/r
(900/100mg) od plus reverse transcriptase inhibitors
(RTIs). RTIs consisted of nucelos(t)ide analogues.
CD4 count, viral load (VL), and routine safety bloods
where measured at baseline, 0, 12, 24, 36 & 48 week
intervals.
with DRV/r (900/100) was 78% at week 12, 94% at
week 24, 100% at week 36 and 100% at week 48.
The proportion (number) of patients achieving HIV
RNA <50 copies/mL in the treatment naïve group on
treatment was 53% at week 12 (16/30), 68% at week
24 (13/19), 88% at week 36 (7/8) and 100% at week
48 (2/2).
In the treatment experienced group the proportion
of patients with HIV RNA <50 copies/mL was at 89%
at week 12, 91% at week 24, 86% at week 36 and
100% at week 48. The overall percentage of patients
in our cohort with VL<50% receiving DRV (900/100)
at weeks 12,24, 36 and 48 was 83%, 87%, 87% and
100%.
25 (13%) patients discontinued therapy and 5
patients were lost to follow up. Main reasons for
discontinuation were GI intolerance (8), elevated liver
function tests (5) and patient discontinuation (5).
CONCLUSIONS: In this cohort of treatment naïve
and experience patients with no background
PI resistance, once daily darunavir/ritonavir
(900/100mg) is both effective in terms of virological
suppression and well tolerated.
RESULTS: 187 patients commenced RTI + DRVr
(900/100). All patients had a phenotypic resistance
test confirming no baseline resistance to DRV. 32/187
patients were naïve to anti-retroviral therapy. 155/187
patients were anti-retroviral treatment experienced
and were switched to DRVr (900/100). Reasons for
DRV use in these patients were virological failure
on current regimen, toxicity on current therapy
or physician decision to switch. 108/155 patients
switched with VL<50 copies/mL.
Data were available for 187, 140, 72 and 32 patients
up to weeks 12, 24, 36 and 48 respectively:
In the treatment naïve group receiving DRVr
(900/100) the median CD4 cell count was 106 and
VL 29564 copies/mL. The proportion of patients
on treatment achieving HIV RNA <500 copies/mL
71
Pharmacology and
Drug Metabolism
73
Abstract 67
Etravirine (ETV, TMC-125) Plasma
Levels in Decompensated Liver
Disease: a Case Report
M Aboud, S Castelino, and R Kulasegaram
Harrison Wing, Department of GU/HIV Medicine,
Guy’s and St Thomas’ Hospitals NHS Foundation Trust,
London, UK
Introduction: Etravirine is a 2nd generation
non-nucleoside reverse transcriptase inhibitor
(NNRTI). In combination with other active agents,
it has been shown to be effective in reducing HIV1 viral load in triple-class resistant individuals
(DUET). Data exists on ETV plasma levels in mild to
moderate liver impairment- manufacturer comment:
‘caution is advised in patients with moderate hepatic
impairment’. But no data exists for severe liver
impairment or decompensated liver cirrhosis- here
the manufacturer says: ‘its use is therefore not
recommended’.
Case: A 50 year old African lady was diagnosed HIVpositive in 1996, and has been on various antiretroviral
combinations since 1998; various switches were made
for side effects, toxicity, virological failure and drug
resistance. In January 2008, she developed ascitis;
investigation for this revealed liver cirrhosis and
portal vein thrombosis. Biopsy was not performed
initially because of anticoagulation. The aetiology
was uncertain, but presumed to be related to prior
antiretroviral therapy.
In January 2008, her regimen of Tenofovir, ddI and
boosted FosAmprenavir was switched to Tenofovir,
ddI, and ETV initially, and then as planned ddI was
switched to boosted Darunavir. As soon as ETV TDM
became available (7 months later) the levels were
measured, and her ETV trough level was found to
be 60 times the recommended. The patient did not
experience any worsening of symptomatology or liver
function, nor indeed any ETV-related side effects over
this period. ETV was discontinued; 2 weeks later her
ETV trough level was 17.9 times the target.
Discussion: Etravirine levels in severe liver
impairment or decompensated liver cirrhosis have not
previously been reported. This case showed excessive
plasma levels of ETV at standard dosing; high levels
persisted even after 2 weeks of discontinuation.
This was not associated with any clinical adverse
outcomes.
ETV levels were very high in this patient with severe
liver impairment; this calls for extreme caution with
its use in such circumstances. We will continue to
measure her ETV levels off ETV therapy.
Abstract 68
Virologic Efficacy of Dual-boosted
Once-daily (QD) Atazanavir,
Fosamprenavir, and Ritonavir
(ATV/FPV/RTV): 48 Week Results
UF Bredeek1, B Williams1, R Feldman1, and T Lancaster2
1 Special Immunology Associates, Tucson, AZ, USA;
2 GlaxoSmithKline, RTP, NC, USA
BACKGROUND: Dual-boosted PI regimens have been
evaluated primarily in HIV-infected subjects with
limited treatment options, and most combinations
studied include LPV/RTV or SQV as one of the
components. The use of dual-boosted PI regimens
in subjects with limited PI resistance is not well
studied.
METHODS: This was an open-label, prospective study
evaluating ATV 400 mg, FPV 1400 mg and RTV 100
mg QD in subjects who were PI naïve or PI experienced
and with HIV RNA >1,000 c/mL. Baseline genotyping
of HIV-1 protease and RT were performed on stored
plasma samples (HIV GenoSURETM, Labcorp).
RESULTS: 19 of 22 subjects completed the study
through 48 weeks (2 withdrew consent; 1 was lost-tofollow-up). At baseline (BL), most subjects (91%) were
Caucasian males with median HIV-1 RNA and CD4+
75
of 4.8 log10 c/mL and 253 cells/mm3, respectively;
11 subjects had baseline resistance mutations, 6
of whom had 1 to 8 PI mutations (1 of whom had a
major PI mutation [L90M]). The duration of prior PI
therapy ranged from 1 to 8.5 years, and the PIs used
were NFV, SQV, LPV/RTV, or IDV. After 48 weeks
of ATV/FPV/RTV, 55% (11/20) and 85% (17/20)
maintained HIV-1 RNA <50 c/mL and <400 c/mL
(M=F), respectively. The median increase in CD4+
cell counts was 221 cells/mm3. Of the 3 subjects with
HIV-1 RNA >400 copies/mL between weeks 24 and
48, none had developed resistance to PIs. The median
fasting lipid values (% change from BL) at 48 weeks
were 171 mg/dL (+28%) for triglycerides, 201 mg/dL
(+34%) for cholesterol, 42 mg/dL (+30%) for HDL,
134 mg/dL (+34%) for LDL, and 4.6 (-3%) for total
cholesterol:HDL ratio.
instantaneous inhibitory potential is clinically very
relevant and depends on the Hill slope. Here we use
viral dynamics simulations to investigate the effect of
multi-round signal amplification on the estimation of
Hill slopes.
CONCLUSIONS: In this study, ATV/FPV/RTV QD
provides virologic suppression and had a moderate
impact on lipids in subjects with limited PI resistance
through 48 weeks of therapy. Larger studies are
needed to further evaluate this regimen as a QD
option for subjects who have developed RT or NNRTI
resistance.
• No net influx of uninfected cells (only
proliferation);
• free virions are depleted exclusively by primary
or secondary infection;
• cellular proliferation and death rates for
uninfected cells are combined in a single parameter
r. For infected cells, this combined rate gradually
declines to reflect the increasing cytopathicity
during the experiment;
• infection is read out by counting the relative
number of infected cells (rather than viral RNA
count)
Abstract 69
A Kinetic Simulation of In Vitro
Pharmacodynamics for HIV Drugs
E Gustin, H Ceulemans, K Cao-Van, K Van Acker, and
HL De Bondt
Tibotec BVBA, Generaal De Wittelaan L11B3, 2800
Mechelen, Belgium
BACKGROUND: The study of HIV viral dynamics
has progressed and yielded insights into the
pharmacodynamics of HIV inhibitors.
Ferguson (2001) predicted that the steepness of the
concentration-response curve for instantaneous
inhibition is overestimated by cumulative viral
inhibition assays. As shown by Shen (2008), the
76
METHODS: An in vitro viral dynamics model was
constructed using a set of 3 differential equations.
The simulated dose-response curves were compared
to experimental data obtained from an antiviral
assay derived from Hertogs (1998) with experimental
dose-response curves collected at day 2, 3 and 4 after
infection.
The in vitro model differs from the simplest in vivo
viral dynamics model (Funk, 2001) in the following
points:
Modeling was done in MathCAD and Berkeley
Madonna. Readouts were simulated at 1, 2, 3 and 4
days.
RESULTS: The model below is consistent with the
experimental data
d/dt U(t) = r × U(t) - kinf × U(t) × V(t)
d/dt I(t) = r × (1-V/ Vmax) × I(t) + kinf × U(t) × V(t)
d/dt V(t) = P(C) × I(t) - kinf × (U(t)+I(t)) × V(t)
with U, uninfected cells; I, infected cells; V, free
virions; r, combined growth-death rate of uninfected
cells; P(C), viral production rate at drug concentration
C as calculated from the Hill equation; Vmax = P(C)/kinf.
Other parameters are r = 0.6931/day, kinf = 0.00025
µL/day and P(no inhibitor) = 250 virions/(cell×day).
All used parameters values are in agreement with
Funk (2001).
These simulations are also confirmed by experimental
observations such as possible apparent virulence
stimulation by the inhibitor (seen as slightly negative
% inhibition values).
The multiple viral lifecycle rounds yield an increased
steepness of the concentration-response curve
(compared to instantaneous inhibition). This
sharpens the signal and requires a transformation to
derive Hill slopes.
CONCLUSION: A thorough understanding of
the kinetics of the multi-round assay through
viral dynamics modeling elucidates the complex
relationship between the amplified readout of the in
vitro multi-round assay and the underlying inhibition
of viral replication, which can be modeled as a Hill
equation.
REFERENCES:
Funk et al., JAIDS 2001; 26(5):397.
Ferguson et al., TiPS 2001; 22(2):97.
Shen et al., Nat Med 2008; 14(7):762.
Hertogs et al., AAC 1998; 42(2):269.
Abstract 70
Lower Levels of Nucleoside Analog
Triphosphates in Primary Human
Macrophages Compared to Human
Lymphocytes Could Impair
Potency of Antiretroviral Drugs in
Human Viral Reservoirs
C Gavegnano, E Fromentin, and RF Schinazi
Center for AIDS Research, Laboratory of Biochemical
Pharmacology, Department of Pediatrics, Emory
University School of Medicine and Veterans Affairs
Medical Center, Atlanta, GA, USA
Background: A significant obstacle in eradication
of human immunodeficiency virus (HIV-1) are
latently infected viral reservoirs. Macrophages
are a latently infected viral reservoir, and cellular
pharmacology of antiretroviral therapy (ART) in
macrophages directly impacts viral loads, resistance,
eradication of systemic virus, and long-term
survival. We sought to determine the intracellular
bioavailability of nucleoside reverse transcriptase
inhibitors (NRTI) in primary human macrophages
and lymphocytes. Our plan is to eventually correlate
the level of phosphorylated nucleoside analogs (active
form of drug) with their known antiviral activity in
lymphocytes and macrophages.
Methods: Human macrophages and PBM cells were
isolated using a Histopaque technique from buffy
coats derived from healthy donors. Macrophages were
stained with CD11b-APC and purity was greater than
99% as determined with FACS. Cells were exposed to
10 µM AZT, ABC, (-)-FTC, or TDF. Drugs and their
phosphorylated derivatives were extracted from the
cells and quantified with LC-MS/MS.
Results: CBV-TP (active form of ABC) was quantified
at 0.415 ± 0.182 µM in PBM cells and 0.010 ± 0.004
µM in macrophages. TFV-DP (active form of TDF)
levels in PBM cells were 394.5 ± 86.6 µM in PBM cells
versus 142.7 ± 121 µM in macrophages. (-)-FTC-TP
77
was detected at 35.3 ± 7.4 µM in PBM cells and 0.667
± 0.116 µM in macrophages. AZT-TP was below the
limit of detection, but AZT-MP was detected (79.6
µM in PBM cells versus 13.8 µM in macrophages).
Conclusions: Levels of (-)-FTC-TP, CBV-TP, and
TFV-DP were significantly lower in macrophages
than human PBM cells (p < 0.05), suggesting that
these nucleosides may be less potent in macrophages.
Quantification of NRTI in both lymphocytes and
macrophages as demonstrated herein provide the
foundation for a comprehensive study to determine
NRTI-TP levels across multiple donors and cell types.
Abstract 71
Lack of Pharmacokinetic
Interaction for Low and Normal
Dose Zidovudine with Amdoxovir
in HIV-1 Infected Individuals
G Asif1, SJ Hurwitz1, PM Tharnish1, RL Murphy2, and
RF Schinazi1
1 Center for AIDS Research, Emory University School of
Medicine/VA Medical Center, Atlanta, GA, USA;
2 Northwestern University, Chicago, IL, USA
BACKGROUND: Amdoxovir (DAPD) inhibits HIV-1
containing the M184V/I mutation in the pol region,
and is rapidly absorbed and deaminated to the active
metabolite, β-D-dioxolane guanosine (DXG). A
recent in silico pharmacokinetic (PK)/enzyme kinetic
study suggested that ZDV 200 mg bid may reduce
toxicity without compromising efficacy relative to the
standard 300 mg bid regimen (Hurwitz et al., AAC,
in press). Therefore, an intense PK clinical study was
conducted using DAPD 500 mg bid alone or with ZDV
200 or 300 mg bid.
3:1 to DAPD or placebo. Full plasma pharmacokinetic
profiles were collected on days 1 and 10, and steady
Cmin was collected on day 5. Complete urine sampling
was performed on Days 9 (0-4 h, 4-8 h, 8-12 h), and
during the 12 h dose interval following the next dose.
A validated LC/MS/MS method was developed to
measure DAPD, DXG, ZDV in plasma and ZDV-5’-Oglucuronide (GZDV) in the urine. Data were analyzed
using non-compartment methods.
RESULTS: Co-administration of DAPD with ZDV did
not affect the systemic clearance (CL/F) (1.0 ± 0.4
and 2.2 ± 0.7 L.h-1.kg-1, respectively) and the renal
clearance (0.26 ± 0.1 and 1.49 ± 0.5 (ZDV+GZDV)
L.h-1.kg-1) of DXG or ZDV, respectively. There were
no statistically significant differences (p > 0.05 using
non-adjusted Student t-test) in the urine elimination
of DXG + DAPD in the “DAPD only” treatment arm
versus “DAPD and ZDV200” (p = 0.44); “DAPD only”
treatment arm versus “DAPD and ZDV300” (p = 0.26);
and “DAPD and ZDV200” versus “DAPD and ZDV300”
(p = 0.7). There were no significant differences in the
elimination of ZDV and its metabolite (GZDV) in
the different treatment arms: “200 ZDV only” versus
“DAPD and ZDV 200” (p = 0.20); “300 ZDV only”
versus “DAPD and ZDV300” (p = 0.07); and “DAPD
and ZDV200” versus “DAPD and ZDV300” (p = 0.79).
CONCLUSIONS: Elimination pattern suggested
no PK interactions between DAPD and ZDV in any
treatment arm. Levels of GZDV in urine were not
affected by co-administered DAPD. Prolonged studies
with DAPD/ZDV (200 mg) are planned with larger
cohorts.
METHODS: Twenty-four subjects, not receiving
antiretroviral therapy (12m, 12f; viral load, VL ≥ 5,000
copies/ml), were randomized to oral DAPD 500 mg
bid, DAPD 500 mg plus ZDV 200 or plus ZDV 300 mg
bid for 10 days. In each arm, subjects were randomized
78
Abstract 72
Metabolism of Highly Active
and Selective 3’-Azido-2’,3’Dideoxypurine Nucleosides in
Primary Human Lymphocytes and
MT-2 Cells
A Obikhod1, E Fromentin1, M Detorio1, SJ Coats2,
N Sluis-Cremer3, JW Mellors3, and RF Schinazi1
1Emory University/VA Medical Center Atlanta, GA, USA;
2 RFS Pharma LLC, Tucker, GA, USA; 3 University of
Pittsburgh, PA, USA
Background: Nucleoside reverse transcriptase
inhibitors (NRTI) are the backbone of combination
anti-HIV-1 therapy. Understanding the metabolism
of these therapeutics in different cell systems
is critical to predicting their potency. NRTI can
compete with endogenous nucleosides for cellular
kinases which are required for conversion to the
HIV reverse transcriptase active triphosphate form.
In addition, variation in dNTP levels could lead to
selective mutations and influence excision activity.
We evaluated the effects of highly potent NRTI such
as 3’-azido-2’,3’-dideoxyguanosine (AZG) and its
6-chloro prodrug (2-amino-6-chloro-3’-azido-2’,3’dideoxypurine-riboside; 6-Cl-AZG) on the dNTP pool
in PBM cells and MT-2 cells to better understand
the difference in anti-HIV activity in these cellular
systems (EC50 = 0.36 µM and 1.64 µM, for AZG and
0.19 µM and 2.8 µM for 6-Cl-AZG, in PBM and MT-2
cells respectively).
versus PBM cells (p = 0.1). However, the levels of
dATP and dGTP were 26 and 100-fold higher in
MT-2 cells than in PBM cells (p < 0.005) and the
levels of dCTP and TTP were 10 and 20-fold higher
in MT-2 cells than in PBM cells (p < 0.05). Increasing
the concentration of AZG from 0 to 50 µM did not
effect NTP levels. The chlorinated prodrug 6-ClAZG crossed the cell membrane in MT-2 cells, but
its phosphorylation metabolites were not found in
either cell line, suggesting its fast bioconversion to
AZG-TP. The amount of intracellular 6-Cl-AZG was
15-fold higher than the amount of AZG itself after
incubation for 20 min in MT-2 cells, as well as the
amount of AZG-TP was 4 fold higher after incubation
with 6-Cl-AZG than with AZG itself.
Conclusion: AZG was successfully converted to
its active metabolite AZG-TP in both cell types. Our
study shows the chlorinated prodrug is transported
faster through the cell membrane, however
after 4 h the levels of AZG-TP formed were not
significantly different in both cell type suggesting
no major advantages of 6-Cl-AZG. Incubation of
AZG at four different concentrations suggested that
phosphorylation reaches steady state at 30 mM. The
higher levels of dNTP in MT-2 decreases the ratio
of AZG/dGTP and provides an explaination for the
weaker antiviral potency of AZG in MT-2 cells.
Method: AZG and 6-Cl-AZG were incubated for 4 h
in human PBM and MT-2 cells at 1, 10, 30 and 50 µM.
Cells were then washed with 1x PBS and metabolites
were extracted with 60% methanol in water and
analyzed by ion-pair chromatography coupled with
positive mode MS/MS (Hypersil GOLD column; 2
mM ammonium phosphate buffer, 3 mM hexylamine
(HMA) and acetonitrile).
Results: The levels of AZG-TP were slightly lower
when the incubation was performed in MT-2 cells
79
Author Index
Author
Abstract
Page
Author
Abstract
Page
Aboud, M. . . . . . . . . . . . . . . . . . . . . 67. . . . . . . . . . . . . . . . . 75
Mtambo, A. . . . . . . . . . . . . . . . . . . . 26. . . . . . . . . . . . . . . . . 28
Arnold, E . . . . . . . . . . . . . . . . . . . . . . 6. . . . . . . . . . . . . . . . . 11
Murphy, RL. . . . . . . . . . . . . . . . . . . 45. . . . . . . . . . . . . . . . . 51
Auwerx, J. . . . . . . . . . . . . . . . . . . . . 32. . . . . . . . . . . . . . . . . 36
Nijhuis, M . . . . . . . . . . . . . . . . . . . . 33. . . . . . . . . . . . . . . . . 37
Bassit, L. . . . . . . . . . . . . . . . . . . . . . 50. . . . . . . . . . . . . . . . . 56
North, TW. . . . . . . . . . . . . . . . . . . . 14. . . . . . . . . . . . . . . . . 17
Berger, EA . . . . . . . . . . . . . . . . . . . . . 9. . . . . . . . . . . . . . . . . 13
Obikhod, A. . . . . . . . . . . . . . . . . . . 72. . . . . . . . . . . . . . . . . 79
Blanco, J. . . . . . . . . . . . . . . . . . . . . . 54. . . . . . . . . . . . . . . . . 60
Pakes, G. . . . . . . . . . . . . . . . . . . . . . . 5. . . . . . . . . . . . . . . . . . . 6
Boucher, CAB . . . . . . . . . . . . . . . . . 21. . . . . . . . . . . . . . . . . 24
Patil, M. . . . . . . . . . . . . . . . . . . . . . . 18. . . . . . . . . . . . . . . . . 20
Bredeek, UF. . . . . . . . . . . . . . . 55, 68. . . . . . . . . . . . . . 61, 75
Pierone, G . . . . . . . . . . . . . . . . . . . . 63. . . . . . . . . . . . . . . . . 68
Buckheit, Jr., RW. . . . . . . . . . . . . . 10. . . . . . . . . . . . . . . . . 14
Polsky, B. . . . . . . . . . . . . . . . . . . . . . 38. . . . . . . . . . . . . . . . . 43
Castor, TP . . . . . . . . . . . . . . . . . . . . 16. . . . . . . . . . . . . . . . . 18
Pop, M . . . . . . . . . . . . . . . . . . . 36, 40. . . . . . . . . . . . . . 40, 45
Chen, L. . . . . . . . . . . . . . . . . . . . . . . 56. . . . . . . . . . . . . . . . . 62
Ray, AS. . . . . . . . . . . . . . . . . . . . . . . 47. . . . . . . . . . . . . . . . . 53
Coats, S. . . . . . . . . . . . . . . . . . . . . . 57. . . . . . . . . . . . . . . . . 63
Sanchez-de la Rosa, R. . . . . . . 64, 65. . . . . . . . . . . . . . 69, 70
De Bondt, HL . . . . . . . . . . . . . . . . . 69. . . . . . . . . . . . . . . . . 76
Sandu, M. . . . . . . . . . . . . . . . . . . . . 27. . . . . . . . . . . . . . . . . 29
Dieterich, D. . . . . . . . . . . . . . . . . . . 37. . . . . . . . . . . . . . . . . 43
Scott, C. . . . . . . . . . . . . . . . . . . . . . . 66. . . . . . . . . . . . . . . . . 71
Divita, G. . . . . . . . . . . . . . . . . . . . . . . 4. . . . . . . . . . . . . . . . . . . 5
Siliciano, RF. . . . . . . . . . . . . . . . . . . . 7. . . . . . . . . . . . . . . . . 11
Dunkle, LM. . . . . . . . . . . . . . . . . . . 44. . . . . . . . . . . . . . . . . 51
Spearman, P . . . . . . . . . . . . . . . . . . . 3. . . . . . . . . . . . . . . . . . . 4
François, KO. . . . . . . . . . . . . . . . . . 58. . . . . . . . . . . . . . . . . 64
Stevenson, M. . . . . . . . . . . . . . . . . . . 1. . . . . . . . . . . . . . . . . . . 3
Gatell, J . . . . . . . . . . . . . . . . . . . . . . 35. . . . . . . . . . . . . . . . . 39
Swan, T. . . . . . . . . . . . . . . . . . . . . . . 41. . . . . . . . . . . . . . . . . 45
Gavegnano, C . . . . . . . . . . . . . . . . . 70. . . . . . . . . . . . . . . . . 77
van der Horst, C. . . . . . . . . . . . . . . 30. . . . . . . . . . . . . . . . . 35
Götte, M. . . . . . . . . . . . . . . . . . . . . . 48. . . . . . . . . . . . . . . . . 54
Wainberg, MA. . . . . . . . . . . . . . . . . 15. . . . . . . . . . . . . . . . . 17
Hartman, TL. . . . . . . . . . . . . . . . . . 17. . . . . . . . . . . . . . . . . 19
Watson, KM. . . . . . . . . . . . . . . . . . . 28. . . . . . . . . . . . . . . . . 29
Hazuda, D . . . . . . . . . . . . . . . . . . . . 13. . . . . . . . . . . . . . . . . 16
Wensing, AMJ. . . . . . . . . . . . . . . . . 29. . . . . . . . . . . . . . . . . 30
Hillier, S. . . . . . . . . . . . . . . . . . . . . . 31. . . . . . . . . . . . . . . . . 36
Wilkinson, J . . . . . . . . . . . . . . . . . . 12. . . . . . . . . . . . . . . . . 15
Hurwitz, SJ. . . . . . . . . . . . . . . . . . . 71. . . . . . . . . . . . . . . . . 78
Witek, J. . . . . . . . . . . . . . . . . . . . . . 53. . . . . . . . . . . . . . . . . 59
Jayaweera, D. . . . . . . . . . . . . . . . . . 51. . . . . . . . . . . . . . . . . 57
Wright, ER. . . . . . . . . . . . . . . . . . . . . 2. . . . . . . . . . . . . . . . . . . 3
Katlama, C. . . . . . . . . . . . . . . . 42, 52. . . . . . . . . . . . . . 49, 58
Zorrilla, C. . . . . . . . . . . . . . . . . . . . . 34. . . . . . . . . . . . . . . . . 38
Khoo, S. . . . . . . . . . . . . . . . . . . . . . . . 8. . . . . . . . . . . . . . . . . 12
Knechten, H . . . . . . . . . . . . . . . . . . 59. . . . . . . . . . . . . . . . . 64
Kožíšek, M. . . . . . . . . . . . . . . . . . . . 22. . . . . . . . . . . . . . . . . 25
Larder, B. . . . . . . . . . . . . . . . . . . . . . 19. . . . . . . . . . . . . . . . . 23
Lefebvre, E. . . . . . . . . . . . . 46, 60, 61. . . . . . . . . . . 52, 65, 67
Lori, F. . . . . . . . . . . . . . . . . . . . . . . . 11. . . . . . . . . . . . . . . . . 14
Margolis, L. . . . . . . . . . . . . . . . . . . . 49. . . . . . . . . . . . . . . . . 55
Massud, I. . . . . . . . . . . . . . . . . . . . . 23. . . . . . . . . . . . . . . . . 25
Mayers, D. . . . . . . . . . . . . . . . . . . . . 43. . . . . . . . . . . . . . . . . 50
McPhaul, T. . . . . . . . . . . . . . . . 24, 25. . . . . . . . . . . . . . 26, 27
Miller, D. . . . . . . . . . . . . . . . . . 39, 62. . . . . . . . . . . . . . 44, 67
Montaner, J. . . . . . . . . . . . . . . . . . . 20. . . . . . . . . . . . . . . . . 23
81
Appendix
83
Late Breaker
Abstracts
85
HIV DART 2008
Late Breaker Abstracts
Abstract 73
Genome-scale RNAi Screen for
Host Factors Required for HIV
Replication
H Zhou1, M Xu1, Q Huang1, AT Gates1, XD Zhang2,
JC Castle3, E Stec4, M Ferrer4, B Strulovici4,
DJ Hazuda1, and AS Espeseth1
Department of 1 Virus and Cell Biology, 2 Biometrics
Research, and 4 Automated Biotechnology, Merck & Co.,
Inc., West Point, PA USA; 3 Rosetta Inpharmatics LLC, a
wholly owned subsidiary of Merck & Co., Inc., Seattle,
WA , USA
BACKGROUND: Human immunodeficiency virus
(HIV)-1 depends on the host cell machinery to support
its replication. The identification of host factors
required for HIV infection may lead to the discovery of
host targets for antiviral drug discovery efforts. The
advent of genome scale siRNA screening technologies
has made it possible to identify previously unknown
genes involved in retroviral replication.
METHODS: To discover cellular factors required
for HIV-1 replication we conducted a genome-scale
siRNA screen. In this screen, we transfected HeLa
P4/R5 cells, which contain an integrated LTR-bGAL
reporter to indicate successful HIV infection, with
siRNAs targeting 19,709 genes. 24h following
transfection, the cells were infected with HIV. B-GAL
activity was then assayed 24h following infection, to
identify host factors associated in early events in HIV
replication (entry through tat-transcription), and
at 96h following infection, to identify host factors
associated with late events in viral replication.
RESULTS: Analysis of the siRNAs that effectively
reduced HIV infection revealed more than 311 host
factors, including 259 that were not previously
linked to HIV. Surprisingly, there was little overlap
between these genes and the HIV Dependency
Factors described following two other siRNA screens.
However, an analysis of the genes identified in both
screens revealed overlaps in several of the associated
pathways or protein complexes, including the SP1/
mediator complex and the NF-kB signaling pathway.
cDNAs for a subset of the identified genes were used
to rescue HIV replication following knockdown of
the cellular mRNA providing strong evidence that
the following 6 genes are previously uncharacterized
host factors for HIV: AKT1, PRKAA1, CD97, NEIL3,
BMP2K, and SERPINB6.
CONCLUSIONS: This study highlights both the power
and shortcomings of large scale loss-of-function
screens in discovering host-pathogen interactions.
The identification of genes with well characterized
roles in HIV infection in this screen validates the
overall approach. Despite this, off target silencing
or failure to silence by a given siRNA pool can lead
to false positives and false negatives in any siRNA
screen. Although further validation of the role played
in HIV replication will be required, the druggable
genes identified in this screen and confirmed by
cDNA rescue, including AKT1, PRKAA1, CD97,
NEIL3, BMP2K, and SERPINB6, all have the potential
to become drug discovery targets.
87
Abstract 74
Quantification of HIV Tropism
by "Deep" Sequencing Shows a
Broad Distribution of Prevalence
of X4 Variants in Clinical Samples
Associated with Virological
Outcome
LC Swenson1, WDong1, T Mo1, C Woods1, A Thielen2,
M Jensen3, C Glascock1, JS Montaner1,4, and
PR Harrigan1,4
1 BC Centre for Excellence in HIV/AIDS, Vancouver,
Canada; 2 Max-Planck Institute for Informatics,
Saarbrucken, Germany; 3 Fortinbras Research, Buford,
GA, USA; 4 Faculty of Medicine, University of BC,
Vancouver, Canada
BACKGROUND: “Deep” sequencing (Roche GS-FLX,
or “454”) detects minority HIV variants in clinical
samples. Here, we performed both deep and standard
sequence analyses of the HIV V3 region from
individuals entering a clinical trial of maraviroc, all of
whom had evidence of X4/DM virus and would not be
expected to show a virological response.
forward and reverse sequencing directions, with
<4% coefficient of variation. The percentage of X4
determined was generally similar whether the PSSM
or geno2pheno interpretations were used, (72% of
samples fell within 4% of each other), despite some
large outliers. Standard sequence analysis failed
to detect X4 in 28% of samples. This was primarily
driven by the low prevalence of X4 – samples which
standard sequence detected as having X4 virus had
a much higher proportion of X4 (median 78% X4;
IQR 38-99% by “deep” analysis) compared to those
missed by standard sequencing (median 9% X4; IQR
2.5-21%); p<<0.05. Preliminary analysis of viral load
reductions in the BID maraviroc arm showed greater
response for those with <10% X4 by deep sequencing/
PSSM (-1.8; -2.2; and -2.6 mean log changes at weeks
2, 4, and 8 respectively) compared to either those
with >10% X4 or to those who received placebo. All of
these showed less than -1.75 log reductions at these
timepoints.
CONCLUSIONS: Deep sequence analyses detect and
quantify low prevalences of X4 HIV within clinical
isolates that are not detected by standard sequence
analysis. A low prevalence of X4 was associated with
improved virological response to maraviroc, even
where the standard Trofile reported DM virus.
METHODS: Screening samples from the Pfizer
A4001029 study were PCR amplified in triplicate
(N=202). Tropism phenotype of all samples was X4
or DM by the standard Monogram Trofile assay as
defined by the study entry criteria. Conventional
(N=153) and “deep” sequencing using the GSFLX was performed using a “barcoding” approach,
allowing the simultaneous analysis of 48 samples
in both directions (N=202) in a blinded manner. V3
genotypes were interpreted using the PSSM and/or
geno2pheno algorithms.
RESULTS: An average of >4000 V3 sequences
were obtained from each sample. All samples had
detectable levels of X4 HIV by deep sequencing, with
4% of patients having <1% inferred X4 by PSSM,
14% having 1-10% X4, 50% having 10-90% X4 and
31% of patients having more than 90% X4. Tight
correlations were generally observed between the
88
Abstract 75
Antiviral Activity and Tolerability
of PRO 140, a Humanized
Monoclonal Antibody to CCR5
JM Jacobson1, MA Thompson2, MA Fischl3,
MS Saag4, BS Zingman5, R Liporace 6, JP Lalezari7,
CJ Fichtenbaum8, DS Berger9, N Stambler10,
Y Rotshteyn10, P D'Ambrosio10, PJ Maddon10,
WC Olson10, and SA Morris10
1 Drexel U. Coll. of Med., Philadelphia, PA, USA;
2 ARCA, Atlanta, GA, USA; 3 U. Miami, Miami, FL, USA;
4 U. Alabama, Birmingham, AL, USA; 5 Montefiore Med.
Ctr., Bronx, NY, USA; 6 Albany Med. Ctr., Albany, NY,
USA; 7 Quest Clinical Res., San Francisco, CA, USA; 8
U. Cincinnati, Cincinnati, OH, USA; 9 NorthStar Med.
Ctr., Chicago, IL, USA; 10 Progenics Pharmaceuticals,
Tarrytown, NY, USA
were +0.06, -1.88 (p<0.0001), and -2.01 (p<0.0001)
for placebo, 5mg/kg and 10mg/kg, respectively. The
mean viral load reduction was >1.5 log10 through Day
22 at 10mg/kg. PRO 140 was generally well tolerated.
Trial enrollment has completed, and updated data
will be presented.
Conclusions: The data confirm the antiviral
activity reported previously for 5mg/kg PRO 140.
A 10mg/kg dose increased the duration of antiviral
effect. The findings indicate the potential for
infrequent IV dosing. SC dosing regimens are also
being evaluated.
Background: PRO 140 is a humanized monoclonal
antibody that binds CCR5 and potently inhibits CCR5tropic (R5) HIV-1 replication. In a prior study, single
5mg/kg IV doses reduced HIV RNA by 1.83 log10 in
subjects with early-stage disease and R5 virus only.
The present study compared 5mg/kg and 10mg/kg IV
doses for antiviral activity and tolerability.
Methods: After IRB approval, nine clinical sites
contributed HIV positive subjects to a randomized,
double-blind, placebo-controlled trial of IV PRO 140.
Entry criteria included HIV RNA >5,000 copies/mL,
R5 virus only, CD4 >300/μL, and no antiretroviral
therapy for 12 weeks. Subjects were randomized to
receive placebo, 5mg/kg PRO 140 or 10mg/kg PRO
140. They were followed for 58 days post-treatment.
An interim analysis was performed on data from the
first 15 subjects.
Results: Interim enrollment was equally distributed
across the treatment groups. Baseline HIV RNA
and CD4 averaged 35,480 cps/mL and 403/μL,
respectively. Mean maximum log10 reductions in HIV
RNA were 0.48 (range 0.15-0.73) for placebo, 1.90
(range 1.44-2.17, p<0.0001) for 5mg/kg PRO 140
and 2.17 (range 2.09-2.26, p<0.0001) for 10mg/kg
PRO 140. At Day 12, mean log10 changes in HIV RNA
89
Abstract 76
Discordance between the Roche
COBAS AmpliPrep/COBAS
TaqMan HIV-1 Assay and the
Roche COBAS Amplicor HIV1 MONITOR Version 1.5 Assay
in a Proof-of-concept Trial in
Treatment-naïve HIV-1-infected
Patients
RL Murphy1, C Zala2, F Fay3, V Calvez4, M Wirden4,
DB DuBois5, K Pietropaolo6, J Molles6, B Belanger6, and
JZ Sullivan-Bolyai6
1 Northwestern University, Chicago, IL, USA and Pierre et
Marie Curie Université Paris 6, Paris, France; 2 ACLIRES
Argentina SRL, Buenos Aires, Argentina; 3 CIBIC
Argentina, Rosario, Argentina; 4 Hôpital Pitié-Salpêtière,
Laboratoire de Virologie, Paris, France; 5 Cenetron,
Austin, TX, USA; 6 Idenix Pharmaceuticals, Cambridge,
MA, USA
BACKGROUND:
Accurate
and
reproducible
quantitation of plasma HIV-1 RNA in subjects
enrolled in clinical trials is critical for the success of
drug development programs. Plasma HIV-1 RNA is
essential for determination of study subject eligibility
and for measurement of early and late virologic
efficacy of drugs in development. During the course
of a Phase Ib/IIa clinical trial of IDX899, a novel
nonnucleoside reverse transcriptase inhibitor, it was
observed that the Roche COBAS AmpliPrep/COBAS
Taqman HIV-1 assay (TaqMan) and the Roche COBAS
Amplicor HIV-1 Monitor version 1.5, Ultrasensitive
version (Amplicor) produced markedly discordant
results.
the TaqMan assay. Patients were referred to the study
by area clinicians who had already done plasma HIV1 RNA (Amplicor) and CD4 counts as part of routine
care. When the discordance was noted, all prior and
subsequent samples were tested by both TaqMan and
Amplicor assays at the certified labs.
RESULTS: 40 patients enrolled into the study, 10 (8
active:2 placebo) each in dosing cohorts of 800 mg,
400 mg, 200 mg and 100 mg administered once
daily. A total of 394 paired samples were tested
with both the TaqMan and Amplicor assays. During
the screening period, 42% of samples had >0.5
log HIV RNA discordance, Amplicor assay results
being higher. This discordance contributed to the
overall virologic screen failure rate of 29% when the
TaqMan was used compared to 8% with Amplicor.
In samples taken throughout the trial, TaqMan
underquantitated by >0.3 log HIV-1 RNA in 44%,
with a mean discordance of -0.3 log HIV-1 RNA lower
overall. Longitudinal analysis of viral load patterns
revealed that assay discordances were not randomly
distributed but related to specific subjects. In a
discrete subgroup of 8 patients (20%), the TaqMan
significantly underestimated HIV-1 RNA at all 9 study
time points.
CONCLUSIONS: TaqMan compared to Amplicor,
underestimated the prevalence of HIV-1 quasispecies
which resulted in the exclusion of a high percentage
of patients and underestimated the change in HIV-1
RNA during the trial.
METHODS: In a single site, double-blind placebocontrolled study, treatment (ART)-naïve patients
with plasma HIV-1 RNA >5000 copies/ml and CD4
count >200 cells/mm3 were enrolled in a 7 day study
with IDX899 monotherapy. At day 8, patients either
started combination ART or were treated with 1
month of lopinavir/ritonavir. Baseline eligibility and
monitoring of HIV-1 RNA were originally done with
90
CME Program
Information
91
HIV DART 2008
Program Information
Sponsored by Emory University School of Medicine,
Office of Continuing Medical Education
Learning Objectives
Upon completion of this activity, participants will be able to:
1. Understand the role of viral targets in the drug discovery and development process
2. Identify novel therapeutic agents and viral targets
3. Develop improved strategies to reduce or eliminate drug-resistance and toxicity
4. Provide insights on novel immunological approaches compatible with clinical drug development
5. Develop approaches to eliminate or eradicate HIV from viral reservoirs
6. Understand the consequences of co-infection with hepatitis B & C on the management of subjects with
HIV infection
Accreditation Statement
Emory University School of Medicine is accredited by the Accreditation Council for Continuing Medical Education
to provide continuing medical education for physicians.
Designation
Emory University School of Medicine designates this educational activity for a maximum of 17 AMA PRA Category
1 Credit(s)TM. Physicians should only claim credit commensurate with the extent of their participation in the
activity.
CME Certificates
In order to obtain your CME certificate for this activity, please complete the Credit Hour Form available at the
registration desk. Forms should be completed in full and returned to the registration desk at the end of the
meeting. Certificates will be mailed 3 - 4 weeks following the activity to the address provided on your registration
form.
Educational Support
This educational activity is supported by unrestricted educational grants from the following:
•Abbott Laboratories
•ACLIRES International Ltd
•American Academy of HIV Medicine
•Boehringer Ingelheim International GmbH
•Bristol-Myers Squibb
•Department of Veterans Affairs
•Gilead Sciences, Inc.
•Idenix Pharmaceuticals
•Merck & Co., Inc.
•National Institutes of Health
•Presidio Pharmaceuticals, Inc.
•RFS Pharma, LLC
•Roche Laboratories
•Samchully Pharm. Co., Ltd
•Schering-Plough Corporation
•Tibotec Therapeutics
93
Faculty/Speaker Disclosure Statement and
Disclosure for Discussions of Off-Label/Investigational Use
of Pharmaceutical Products
In accordance with ACCME Standards for Commercial Support of Continuing Medical Education and Emory
University School of Medicine’s disclosure policy for CME activities, faculty members have been asked to disclose
any relationship they may have with commercial supporters of this CME activity or with companies providing
products or medical equipment that may have relevance to the content of their presentations. Such disclosure is
intended to provide participants with sufficient information to evaluate whether any given presentation has been
influence by the faculty’s relationships(s) or financial interest with said companies.
This activity may include information regarding the off-label and/or investigational use(s) or various
pharmacologic agents. The faculty have disclosed below if they will be discussing a product which is still
investigational or not labeled for the use under discussion
Note: If the disclosure information was not received before the production of the syllabus, “refused to disclose”
is listed below and the moderator will state the faculty’s disclosure information during the introduction of their
presentation.
Course Directors and Planning Committee Members Disclosure Information:
Organizing Committee
David Cooper
GSK, Gilead Sciences, BMS, Roche, Pfizer, Merck, Abbott, Boehringer-Ingelheim,
Johnson & Johnson (investigator, advisor and speaker).
Joep Lange
Nothing to disclose.
Robert Murphy
Idenix, Genetic Immunity, Viryxsys (consultant); Idenix (stockholder);
Bristol-Myers Squibb, Abbott Laboratories (grant support).
José RodriguezOrengo
Raymond F. Schinazi
Founder and major shareholder: Pharmasset, Inc., Idenix Pharmaceuticals, RFS
Pharma LLC; Will discuss any of the drugs from these companies that might be
presented.
Scientific Advisory Committee
94
Françoise
Brun-Vezinet
Sal Butera
Pedro Cahn
Bonaventura Clotet
Boehringer Ingelheim, Bristol Myers Squibb, Gilead, GlaxoSmithKline, Janssen,
Merck, Pfizer, Roche, Siemens (consulting fees or
paid advisory board).
Steven Deeks
Pfizer, Merck, Gilead, BMS (research support); GSK, Roche, Schering-Plough, Panacos,
Argos (ad hoc consulting).
Courtney Fletcher
Joel Gallant
Gilead Sciences, Merck, Pfizer, Roche Pharmaceuticals, Tibotec (research support);
Abbott Laboratories, Gilead Sciences, Koronis (DSMB member); Bristol-Myers Squibb,
Gilead Sciences, Merck, Pfizer, RAPID Pharmaceuticals, Schering-Plough, Tibotec
(Advisory Board); Abbott Laboratories, GlaxoSmithKline, Vertex (consultant); Abbott
Laboratories, Gilead Sciences, GlaxoSmithKline, Monogram Biosciences, Tibotec
(honoraria).
José Gatell
Have received research grants and honoraria for speaking or advisory board.
Brian Gazzard
Matthias Götte
Eric Hunter
John Idoko
Christine Katlama
Paolo La Colla
Alain Lafeuillade
Hiroaki Mitsuya
Julio Montaner
Alan Perelson
Praphan Phanuphak
Richard Pollard
Bruce Polsky
Idenix Pharmaceuticals (stockholder); Gilead Pharmaceuticals (consultant, Speaker
Bureau member); Bristol-Myers Squibb (spouse employed, stockholder).
Francois Raffi
Douglas Richman
Ian Sanne
Charles van der
Horst
GSK, Abbott, BMS and Boehringer provide medications for my CDC funded research
study in Malawi. GSK and Abbott have also both contributed funds for specific lab
tests as part of that study. All four companies and Gilead support my HIV continuing
education meeting. Gilead provides funding for residency training for Malawian
physicians sponsored by UNC. I have less than $10,000 in stock in Roche and BMS
each.
Stefano Vella
Mark Wainberg
Speakers, Moderators and Panelists’ Disclosure Information:
Joeri Auwerx
We have a long term collaboration with Gilead Sciences on structural studies of
HIV-1 RT with tenofovir (Gilead markets Viread). I visit and consult periodically with
scientists at Gilead, but not within the last 12 months.
Leda Bassit
Edward Berger
Charles Boucher
Robert Buckheit
Edward Arnold
95
Douglas Dieterich
Gilles Divita
Lisa Dunkle
Amy Espeseth
Matthias Götte
P. Richard Harrigan
Daria Hazuda
Sharon Hillier
Schering-Plough Corporation (employee).
I have received grants or honoraria and/or consulted for a variety of pharma and
diagnostic companies. The research presented here was supported by an investigator
initiated research grant by Pfizer.
Merck & Co. (employee).
Christine Katlama
BMS, Gilead, Tibotec, GSK, Roche (grants/research support, consultant, honorarium,
speaker bureau); Virco, Vertex (consultant, honorarium, speaker’s bureau); Abbott,
BIPI (honorarium, speaker bureau).
Saye Khoo
Joep Lange
Brendan Larder
Eric Lefebvre
Employee of Tibotec.
Franco Lori
Employee as CEO and President of Virostatics.
Leonid Margolis
Douglas Mayers
Julio Montaner
Stephen Morris
Monique Nijhuis
Thomas North
Chief Medical Officer for Idenix Pharmaceuticals.
Senior Director Clinical Research, Progenics, Inc.
Idenix, Genetic Immunity, Viryxsys (consultant); Idenix (stockholder); Bristol-Myers
Squibb, Abbott Laboratories (grant support).
Richard Pollard
Dushyantha
Jayaweera
Robert Murphy
Bruce Polsky
Adrian Ray
José RodriguezOrengo
Ian Sanne
Idenix Pharmaceuticals (stockholder); Gilead Pharmaceuticals (consultant, Speaker
Bureau member); Bristol-Myers Squibb (spouse employed, stockholder).
I am employed by and hold stock in Gilead Sciences, Inc., the marketer of HIV drugs
(tenofovir and emtricitabine) and a company involved in studying clinical candidates
for the treatment of HIV (including GS-9131/GS-9148 and GS-9137). My talks will
present balanced discussions of drugs and drug candidates from Gilead and other
companies.
Robert Siliciano
Founder and major shareholder: Pharmasset, Inc., Idenix Pharmaceuticals, RFS
Pharma LLC; Will discuss any of the drugs from these companies that might be
presented.
Paul Spearman
Mario Stevenson
Tracy Swan
Raymond F. Schinazi
96
Roche, Gilead, BMS, Novartis, Boehringer Ingelheim (grants); Roche, Gilead, BMS,
Novartis (consulting and lecturing).
Charles van der
Horst
GSK, Abbott, BMS and Boehringer provide medications for my CDC funded research
study in Malawi. GSK and Abbott have also both contributed funds for specific lab
tests as part of that study. All four companies and Gilead support my HIV continuing
education meeting. Gilead provides funding for residency training for Malawian
physicians sponsored by UNC. I have less than $10,000 in stock in Roche and BMS
each.
Mark Wainberg
John Wilkinson
James Witek
Employee and stockholder of Johnson & Johnson.
Elizabeth Wright
Carmen Zorrilla
Tibotec (clinical trial sponsorship, Advisory Committee).
This activity is being sponsored by Emory University School of Medicine. The medical school has no significant
relationship with the commercial companies whose products are services are being discussed in this educational
activity.
97
Informed Horizons presents...
Upcoming Meetings
HIV DRUG RESISTANCE
workshop
basic principles & clinical implications
*$-%'),'("%' 2009
XVIII International HIV Drug Resistance Workshop:
Basic Principles & Clinical Applications
June 9-13, 2009
Fort Myers, Florida
HEP DART 2009:
Frontiers in Drug Development for Viral Hepatitis
December 6-10, 2009
Kohala Coast, Hawaii
This workshop is renowned for the quality of the data
presented and the depth of the scientific interaction and
debate.
The focus of HEP DART 2009 is to assemble clinicians,
researchers, and basic scientists together to advance our
knowledge of the ongoing drug development processes
in the treatment of hepatitis B and hepatitis C.
For more information visit our website at www.informedhorizons.com
Coming in 2009...
From the American Academy
of HIV Medicine:
Fundamentals
of Global HIV
Medicine
Relevant and practical core
HIV knowledge for global HIV
medical care providers
For more information,
contact IHL Press at
info@ihlpress.com

Volume 4, Supplement 1

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