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Anticipating the results of the AIDSVAX efficacy trial

October 14, 2002

24 October 2002--Results of the world's first human trial to determine the efficacy of an investigational vaccine to prevent HIV/AIDS are expected early next year.

The vaccine candidate, called AIDSVAX and developed by California biotechnology firm VaxGen Inc., is intended to protect people uninfected with HIV from becoming infected. Whether AIDSVAX in fact does this is the subject of the 5000-volunteer, three-year trial now finishing in the US, Canada and Netherlands.

In advance of this study's conclusion, the nonprofit AIDS Vaccine Advocacy Coalition, an IAVI partner, has released a comprehensive background document on what AIDSVAX is, how the efficacy trial was conducted and what the possible outcomes are.

"This vaccine has been the subject of both skepticism and optimism," said Chris Collins, AVAC's Executive Director. But whatever the results, "research like this trial is essential to moving the field forward."

AIDSVAX is not the only preventive AIDS vaccine in development, but it is the one furthest along. AIDSVAX will be the first ever to have completed all three of the phases of human trials required to determine if a vaccine is efficacious or not. Other candidates are in earlier phases of trials. (More on the state of AIDS vaccine science)

"We applaud VaxGen for their heroic leadership toward ending what likely will be the worst infectious epidemic of recorded time," said Seth Berkley, MD, President and Chief Executive Officer of IAVI. "But it is a tragedy that after 20 years of AIDS, only VaxGen is this far along. The stakes are too high to bet on any one AIDS vaccine--be it AIDSVAX or another single approach."

Should AIDSVAX not prove efficacious, "it could be tempting to conclude that this means that an AIDS vaccine is not possible. In fact, experts worldwide are confident that an AIDS vaccine is possible. We simply have not tried all of the options yet--AIDSVAX is more or less a first attempt," Dr. Berkley said.

If, on the other hand, AIDSVAX is found to help prevent HIV infection, "this will be a great day for the field and world," Dr. Berkley said. "But our challenge will not be over. There will then be the Herculean task of assuring that everyone who could benefit from an AIDS vaccine will have access to it." (More on assuring access to future AIDS vaccines)

A companion trial of AIDSVAX in Thailand is also underway. Results are expected in late 2003 or early 2004.