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Thai trial confirms earlier results that VaxGen's AIDSVAX is not efficacious-IAVI response

November 12, 2003

NEW YORK, 12 November 2003—VaxGen Inc. announced today that its preventive AIDS vaccine candidate, AIDSVAX, although safe, did not prove efficacious in a large-scale human trial conducted in Thailand over the past four years. This confirms the results, announced in February this year, of a companion North America-Europe large-scale trial of AIDSVAX, which also found that the vaccine candidate was safe but not efficacious.

VaxGen conducted the two large-scale trials of AIDSVAX in companion to test how the vaccine might work in different settings.

AIDSVAX, the first and only preventive AIDS vaccine candidate to be tested in a large-scale human trial, was designed to prevent people who are uninfected with HIV/AIDS from contracting the disease. Expert consensus is that a preventive vaccine is the best hope to end the spread of the HIV/AIDS epidemic, now infecting 15,000 people each day.

“The search for a vaccine to end the spread of AIDS goes on,” said Dr. Seth Berkley, President and CEO of the International AIDS Vaccine Initiative (IAVI). “Other AIDS vaccine candidates, employing promising design strategies that are different from AIDSVAX’s, are in trials, and more are being developed.”

“Although AIDSVAX was found not to work, the trials themselves were a success,” Dr. Berkley said. “VaxGen demonstrated that it is possible to conduct large-scale trials of AIDS vaccines in both industrialized and developing countries,” Dr. Berkley said.

IAVI ( is a nonprofit scientific organization working to speed the search for a preventive AIDS vaccine. IAVI sponsors public-private partnerships to conduct research to develop vaccine candidates. IAVI’s major financial supporters include the Bill & Melinda Gates Foundation; the Rockefeller, Sloan and Starr foundations; the World Bank; BD (Becton, Dickinson and Co.); and the governments of Canada, the Netherlands, the United Kingdom, the United States, Ireland, Denmark, Norway and Sweden.