Preliminary analysis of data from a clinical trial testing two candidate HIV vaccines given together shows that the combination is safe and can stimulate diverse immune responses against HIV. The findings will be discussed by the study's principal investigator, Robert Belshe, M.D., of Saint Louis University, on Tuesday morning, July 13, at the International Society for Sexually Transmitted Diseases Research meeting in Denver.
This is the second Phase 2 HIV vaccine trial, and the largest to date, sponsored by the National Institute of Allergy and Infectious Diseases (NIAID). The trial, known as AVEG 202/HIVNET 014, is being carried out at 14 sites nationwide by two NIAID-sponsored networks, the AIDS Vaccine Evaluation Group (AVEG) and the HIV Prevention Trials Network (HIVNET). Dr. Belshe heads the Saint Louis University AVEG site.
Earlier studies in volunteers at low risk of HIV infection showed this combined vaccine approach held promise for activating both components of the immune system. One vaccine, ALVAC-HIV vCP205, stimulates cellular immunity, resulting in cytotoxic T cells (CTLs) that can kill HIV-infected cells. The other vaccine, SF-2 rgp120, stimulates production of HIV neutralizing antibodies, which can stop HIV from infecting cells. The vaccines contain only selected HIV genes or proteins, and not the whole virus, so an individual cannot become infected from receiving the vaccines.
The current trial, which opened in May 1997, enrolled 435 healthy men and women not infected with HIV. Because the primary goal of this study is to assess the immune response and safety of the vaccine combination in individuals at increased risk of becoming infected with HIV, more than 80 percent of the participants had recent histories of injection drug use or high-risk sexual behavior. All participants received extensive and repeated counseling on reducing high-risk behaviors.
Each participant was randomly assigned to one of three study groups.
Contact: Laurie K. Doepel
NIH/National Institute of Allergy and Infectious Diseases