HIV vaccine trial cuts infection by 31.2%

A Phase III clinical trial involving more than 16,000 adult volunteers in Thailand has demonstrated that an investigational HIV vaccine regimen was safe and modestly effective in preventing HIV infection. According to final results released by the trial sponsor (the U.S. Army Surgeon General), the prime boost combination of Sanofi Pasteur’s ALVAC vaccine and AIDSVAX, developed by VaxGen and now owned by the Global Solutions for Infectious Diseases, lowered the rate of HIV infection by 31.2% compared with placebo.

More than 16,000 HIV-negative men and women between the ages of 18 to 30 participated in the study; half of these participants received the prime-boost vaccine regimen and half received placebo. Volunteers received vaccinations over the course of six-months and were followed for an additional three-years.

“This is the first HIV vaccine candidate to successfully reduce the risk of HIV infection in humans. We are very excited and pleased with the outcome of this trial and congratulate all those who participated in it,” said Lieutenant General Eric Schoomaker, Surgeon General, U.S. Army. “In addition, this study is an outstanding example of international and interagency collaboration involving many partners from the Thai and U.S. governments, private companies, non-profit organizations and volunteers.”

“The study results, representing a significant scientific advance, are the first demonstration that a vaccine can prevent HIV infection in a general adult population and are of great importance,” the World Health Organization (WHO) and the Joint UN Programme on HIV/AIDS (UNAIDS) said in a statement, calling the results of the trial encouraging.

Michel DeWilde, R&D senior vice president for Sanofi Pasteur, noted that “albeit modest, the reduction of risk of HIV infection is statistically significant” and “this is the first concrete evidence, since the discovery of the virus in 1983, that a vaccine against HIV is eventually feasible”.

In the final analysis, 74 placebo recipients became infected with HIV compared to 51 in the vaccine regimen arm.