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The Center for Vaccine Development at the School of Medicine has begun to enroll the first volunteers for the largest trial ever in the search for a vaccine against HIV, the virus that causes AIDS.
This Phase III study is the first time an investigational HIV vaccine will be evaluated in a large-scale prevention study in humans in the United States.
"The study will provide important new information about which vaccine-induced immune responses can protect against HIV," said Dr. Geoffrey J. Gorse, M.D., professor of internal medicine in the division of infectious diseases and immunology.
The study will involve approximately 5,000 volunteers at multiple sites in North America, including St. Louis. It is sponsored by the maker of the vaccine, VaxGen Inc. of South San Francisco, Calif.
Phase III trials are designed to study the safety and efficacy of an experimental vaccine or drug and, if successful, are a critical step in the clinical testing process that precedes an application to the Food and Drug Administration (FDA) for approval to license and market the product.
The vaccine, AIDSVAX, is designed to protect against strains of HIV-1 in the Americas, Western Europe, Australia and Southern Asia, where more than 3 billion people remain at risk from these strains of HIV.
AIDSVAX is a preparation of recombinant gp120 (rgp120), the glycoprotein from HIV's envelope that binds to the surface of T-cells. Injecting rgp120 into the body stimulates the production of antibodies that, in any future exposure to HIV, could prevent infection.
The current formulations of AIDSVAX are "bivalent," so-called because they each are developed from recombinant forms of two strains of HIV. The "bivalent" vaccines induce a greater immune response in animals to a broader range of strains of the HIV virus than did the previous "monovalent" vaccine.
The Phase III trial is designed for an approximate three-year study period. In addition to St. Louis, clinics in Chicago, Denver, Los Angeles and Philadelphia are innoculating volunteers this month. Eventually, a total of approximately 50 clinics will be involved in the North American study. An additional 2,500 volunteers will be recruited in a related study planned for Thailand. There are 30 million people worldwide already infected with HIV, and more than 16,000 new infections each day.
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