Abstract Book Vol. 2 [International Conference on AIDS (14th: 2002: Barcelona, Spain)]

XIV International AIDS Conference

Abstracts WeOrD1299-WeOrD1314 149

WeOrD1299 Conduct of the first phase III efficacy trial of a
preventive HIV-1 vaccine (AIDSVAX~ B/B) in North
America and Europe
C. Harro', F. Judson2, S. Brown3, R. Coutinho4, V. Popovic5, M. Gurwith5,
Vax004 Study Team5. 'Johns Hopkins Center for Immunization Research,
VaxGen, Inc., 1000 Marina Blvd., Brisbane, CA 94005, United States; 2Denver
Public Health Department, Denver, CO, United States; 3AIDS Research Alliance,
W Hollywood, CA, United States; 4Municipal Health Service, Amsterdam, The
Netherlands; 5 Vaxgen, Inc., Brisbane, CA, United States
Background: Efficacy trials of HIV vaccines face unique challenges: recruitment
and retention of large at-risk cohorts, and potential trial-related social harms due
to discrimination or lack of opportunities.
Methods: A randomized, double-blind, placebo-controlled, 3-year study to evaluate efficacy of the bivalent rgpl20/HIV-1 vaccine (AIDSVAX~ B/B) to prevent
sexually transmitted HIV infection is underway in North America and Europe. Subjects are vaccinated at months 0, 1, 6, 12, 18, 24 and 30. Education to prevent
social harms is conducted throughout the trial.
Results: 5109 men who have sex with men (MSM) and 309 women at heterosexual risk (WAHR) were enrolled 6/98-10/99. Participants are young (median
36 years), white (83%) and well educated (61%>college education). Many volunteers were at high risk of HIV infection in the 6 months prior to enrollment:
non-injection drug use 63%, sexually transmitted diseases 14%, unprotected anal
sex with HIV+ male partners 19% (MSM), unprotected vaginal sex with male
HIV+ partners 16% (WAHR). Two years after full enrollment, high retention (89%)
has been achieved. Most common adverse event (AE) was pain at injection site
(87%). No unexpected vaccine related serious AEs were reported. Social harms
were reported by 3% of volunteers; of these, 97% were resolved and the most
common were mild disturbances of personal relationships (63%).
Conclusion: The world's first HIV vaccine efficacy trial has been successfully enrolled with good retention and vaccine safety after the first 2 years. Education has
been effective to prevent trial-related social harms. The trial is scheduled to end
in late 2002.
Presenting author: Kesinee Yip, VaxGen, Inc., 1000 Marina Blvd., Brisbane, CA
94005, United States, Tel.: [phone], Fax: [phone], E-mail: kyip
@vaxgen.com
WeOrD1 300 Ongoing follow-up of injecting drug users (IDUs)
in the AIDSVAX~B/E vaccine efficacy trial in
Bangkok, Thailand
K. Choopanyal, J. Tappero2, P. Pitisuttithum3, S. Vanichseni', D. Kitayaporn 3,
U. Sangkum 4, K. Hiranrus4, D. Francis5. 'Bangkok Vaccine Evaluation Group,
Bangkok Vaccine Evaluation group, Taksin Hospital, Somdet Chaophraya Road
Klongsarn, Bangkok 10600, Thailand; 2Thai MOPH - US CDC Collaboration,
Nonthaburi, Thailand; 3Mahidol University Bangkok, Thailand; 4Bangkok
Metropolitan Administration, Bangkok, Thailand; I VaxGen, Inc., Brisbane, CA,
United States
Background: The world's first phase Ill HIV vaccine trial (bivalent B[MN]/E[A244]
rgpl20; AIDSVAX~B/E, VaxGen, Inc., USA) in a developing country is taking
place in Thailand among IDUs followed throughout 17 Bangkok Metropolitan Administration drug treatment clinics.
Methods: Consenting HIV-seronegative IDUs were randomized to receive
AIDSVAX~B/E (300ug of each antigen) or placebo (1:1 ratio) at months 0, 1,
and 6, with booster doses at months 12, 18, 24, and 30. All participants are being
followed for 3 years to detect efficacy with a lower-bound 95% CI of at least 30%
(1st endpoint, infection measured by ELISA and Western blot). Interim safety and
efficacy analyses are conducted by an independent data and safety monitoring
board (DSMB).
Results: From March 1999 through August 2000, a total of 4,943 IDUs were
screened, of which 1,689 (34%) were HIV-seropositive. A total of 2,545 subjects
were enrolled with a median age of 26 years; 93% were male. Through Nov 30,
2001, follow-up has been excellent (1.1% withdrew consent, 1.8% lost to followup); 5.8% of follow-up visits have taken place in jail or prison. No vaccine-related
serious adverse events have been reported. Pain and tenderness at the injection site is the most commonly experienced adverse event (65%). Overall immunization compliance was 98%, with 2,513 (99%) subjects receiving the 2nd
dose, 2,432 (98%) receiving the 3rd dose and 2,352 (97%) receiving the 4th
dose, respectively. The DSMB advised trial continuation following safety reviews
in September 1999, April and October 2000, and April and October 2001.
Conclusion: Follow-up has been excellent and immunizations well tolerated. A
combined interim safety and efficacy DSMB review is scheduled for late 2002;
final results are expected in late 2003.
Presenting author: Kachit Choopanya, Bangkok Vaccine Evaluation group,
Taksin Hospital, Somdet Chaophraya Road Klongsarn, Bangkok 10600, Thailand,
Tel.: [phone], Fax: [phone], E-mail: [email protected]

WeOrD 301 The demand for an HIVIAIDS vaccine among
high-risk groups: Does risk matter?
C. Suraratdecha', M. Ainsworth2, V. Tangcharoensathien3. 1Sukhothai
Thammathirat Open University, School of Economics, Sukhothai Thammathirat
Open University, Pakkred, Nonthaburi 11120, Thailand; 2 World Bank,
Washington, D.C., United States; 3Health Systems Research Institute, Bangkok,
Thailand
Background: Sex workers (SW) and intravenous drug users (IDU) are at extremely high risk of HIV infection in Thailand. Whether an AIDS vaccine that reduces the risk of infection would bring substantial private benefits to high-risk
groups (HRG) and indirectly reduce the spread of HIV depends critically on their
perspectives on the vaccine, private demand, and willingness to be vaccinated.
Methods: We interviewed 600 direct and indirect SW in 6 of Thailand's 76
provinces and 200 IDU in 4 provinces. Respondents were asked whether they
were willing to pay for either 50% or 95% effective vaccine that lasts 10 years,
is safe, has no side effects and no benefits for those infected. The IDU were offered a vaccine price of $25. The SW were randomly assigned one of four prices
($12.50, $25, $125, $500).
Results: At a price of $25, 79.7% of SW and 76.5% of IDU would be willing to
pay for a 95% effective AIDS vaccine. Demand was not significantly affected by
efficacy and was substantially higher than that found in a study of private demand
in the general population, confirming that risk of HIV infection plays an important role in determining vaccine demand. 5.5% of IDU and 4.5% of SW would not
agree to be vaccinated even if the vaccine were free, mainly because they felt that
they were not at risk. Among those willing to be vaccinated, 4.8% of IDU and 4%
of SW reported that they might be less likely to practice safe injecting behavior or
condom use if vaccinated.
Conclusions: The success of public programs to prevent HIV transmission
among HRG and the general population via AIDS vaccine will depend on the
demand and willingness to be vaccinated. As HRG are socially stigmatized and
potentially difficult or expensive to reach through public programs, the evidence
suggests that they might independently seek an AIDS vaccine if it were made accessible, reducing the burden of the public sector in targeting populations based
on risk.
Presenting author: Chutima Suraratdecha, School of Economics, Sukhothai
Thammathirat Open University, Pakkred, Nonthaburi 11120, Thailand, Tel.:
[phone], Fax: [phone], E-mail: [email protected]
WeOrD1302 Minimizing Regulatory Delays in the Approval and
Licensure of New HIV/AIDS Vaccines
M.T. Isbell1, R. Widdus2, L. Williams', D. Gold'. 'International AIDS Vaccine
Initiative, 250 West 24th Street, # 3GW New York NY, 10011, United States;
2IPPPH, Geneva, Switzerland
Issue: A generation or more is currently required before new vaccines receive
extensive use in the world's poorest countries, even though these products could
prevent substantial morbidity and mortality. To reduce the likelihood that such a
situation will occur with respect to HIV/AIDS vaccines, IAVI released at the Durban AIDS Conference a blueprint entitled "AIDS Vaccines for the World: Preparing Now to Ensure Access." According to this IAVI analysis, fragmented and
often-inconsistent regulatory requirements in multiple jurisdictions threaten to delay by many years effective use of new HIV/AIDS vaccines when these products
emerge.
Description: To clarify potential regulatory delays and to devise strategies for
overcoming them, IAVI has initiated a worldwide consultation of leading experts,
including research scientists (public and private sectors), regulatory officials (in
developing and developed countries), and lawyers, policy experts, and multilateral agencies.
Lessons Learned/Recommendations: IAVI will present the findings of its global
consultation, including recommendations for policy reform. Issues addressed will
include:
- What fast-track mechanisms may be developed in advance to facilitate swift,
comprehensive assessment of the safety, efficacy and quality of new vaccines?
- What policies and practices are needed to address the fact that the societies in
which key regulatory agencies exist often have widely varying risk-benefit considerations with respect to new HIV/AIDS vaccines?
- How may capacity be enhanced in developing countries to ensure their timely,
effective review of new vaccines?
Presenting author: Michael Isbell, 250 West 24th Street, # 3GW, New York NY,
10011, United States, Tel.: [phone], E-mail: [email protected]
WeOrD1314 SAMMA is a novel microbicide which inhibits
human immunodeficiency virus and herpes
simplex virus entry

B. Herold', I. Bello', M. Marcellino', M. Dzeuzelewski', N. Cheshenkol,
F. Francois', V. Mas Casullo', R. Anderson2, C. Chany2, L.J.D. Zaneveld2,
D.RP. Waller3, M.E. Klotman'1. ' Mt. Sinai School of Medicine, New York, NY,
United States; 2Rush-Presbyterian St. Luke's Medical Center, Chicago, Ill,
United States; 3University of Illinois at Chicago, Chicago, III, United States
Background: Although renewed efforts in vaccine development have provided
valuable insight, a protective vaccine may not be available in the near future. Top