HIV Vaccine Trial in Thailand to Continue

Independent data and safety monitoring board (DSMB) found no safety concerns.

Fort Detrick, Md. - July 17, 2008 - A large, multi-center HIV vaccine clinical trial in Thailand will continue since there are no safety concerns with the vaccine. This recommendation was made during a scheduled July 16 review of the trial data by an independent data and safety monitoring board (DSMB).

While no conclusions can be drawn from this DSMB meeting regarding the efficacy of the vaccine, the DSMB did review the data for statistical futility and recommended that the trial continue. Final analysis is scheduled to begin during the summer, 2009.

The DSMB monitoring the study has met seven times since 2003 to review the trial for potential safety issues. The DSMB found no safety concerns at any time.

The study, referred to as RV 144, is sponsored by the U.S. Army Surgeon General and is being conducted by the Thailand Ministry of Public Health with support from the U.S. Army Medical Research and Materiel Command and the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH).

The Phase III clinical study, which began in October 2003, is testing a prime-boost combination of two vaccines based on HIV subtypes that circulate in Thailand. The priming vaccine, known as ALVAC-HIV, was developed by sanofi pasteur and is a canary-pox vector that elicits an immune response from T cells, which can kill HIV-infected cells. The booster vaccine, AIDSVAX B/E®, which was originally developed by VaxGen and is now licensed to Global Solutions for Infectious Diseases, elicits an antibody response from the immune system. Neither vaccine can cause HIV infection.

A total of 16,402 HIV-negative men and women between the ages of 18 and 30 participated in the study; half of these participants received the prime-boost vaccine regimen and half received placebo. Vaccinations ended in July 2006, and volunteers have continued to receive an HIV test every six months for three years following vaccination, in addition to counseling on how to prevent becoming infected with HIV.

Volunteers who acquired HIV infection during the trial are being given free access to HIV care and treatment, including highly active antiretroviral therapy, according to the guidelines of the Thai Ministry of Public Health. They will also be offered extended follow-up in a separate study.

Findings from this clinical study should significantly contribute to the scientific understanding of HIV vaccine development and provide techniques for building clinical trial capacity and engaging communities for HIV vaccine research. The important knowledge gained through this clinical trial will inform future HIV vaccine studies.

An HIV vaccine continues to be our best hope for ending the HIV pandemic. The U.S. Army is committed to developing a globally-effective HIV vaccine to protect U.S. troops from infection and reduce the global impact of the disease.

The U.S. Army would like to thank the Thai men and women who consented to participate in this trial and whose continued high rate of participation is essential to its success.

Media inquires can be directed to USMHRP Communications Office at 301-251-5000 or

The U.S. Military HIV Research Program (USMHRP) is a tri-service effort headed by the Walter Reed Army Institute of Research in collaboration with the U.S. Army Medical Research and Materiel Command.

Last Modified Date: 22-Sep-2009