SAN FRANCISCO — A $119 million federally funded experiment in which an AIDS vaccine is being tested on 16,000 volunteers in Thailand is doomed to fail and should never have been started, 22 leading HIV researchers charge.
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The scientists allege the Thai volunteers are receiving a crude cocktail made of two antiquated AIDS vaccines, each of which failed previous human tests.
“They are taking two failed products and hoping that if they are combined that they are going to work,” said Dennis Burton, an AIDS researcher at the Scripps Research Institute in La Jolla. “Everything I’ve seen about the Thai trial suggests that it doesn’t have a prayer.”
Burton and 21 other researchers — including Robert Gallo, co-discoverer of the AIDS virus — signed a short opinion piece published in Friday’s issue of the journal Science.
The experiment is funded by the National Institutes of Health and the Pentagon and is being carried out by the Thai government.
Government defends research
U.S. government officials defended the research, saying it could yield a new weapon against a disease that has killed 28 million people and infected 42 million more, most of them in Africa.
But the 22 scientists complained the Thai experiment is diverting critical funding and energy from more promising vaccine candidates, including some of their own.
What’s more, they said they fear public and political confidence in AIDS vaccine research will be hurt if the Thai experiment fails as they expect. It would be the third major flop of a large-scale AIDS vaccine experiment, and the second failure in Thailand.
Last year, AIDSVAX, a vaccine created by Brisbane, Calif.-based VaxGen Inc., failed to protect volunteers against the disease in a 5,400-person North American trial. The same vaccine failed in a 2,400-volunteer trial in Thailand in November.
Since then, VaxGen essentially has abandoned its pursuit of an AIDS vaccine.
Despite those failures, AIDSVAX is one of the vaccines being used in the current trial. It’s the second part of a one-two punch called “prime boost” that its supporters see as the most promising approach to defeat the AIDS virus by provoking several different immune responses.
A VaxGen spokeswoman declined comment.
The prime piece of the Thai vaccine is ALVAC, created by Aventis Pasteur. An Aventis scientist defended the vaccine as worthy of continued development.
But the critics argue the NIH scrubbed a U.S.-based trial with the same two-vaccine cocktail two years ago because of failures in a smaller experiment.
That trial was canceled, in part, because the Thai test was starting, government officials said.
The U.S. trial targeted a different AIDS strain than the Thai test and was more narrowly focused. Still, the 22 scientists argue the two tests are similar enough to warrant cancellation of the Thai experiment.
Researchers already have inoculated about 500 volunteers since the experiment began in September and plan to give shots to 15,500 more people over the next two years. It will take about five years to see results.
U.S. government officials and advocacy groups contend the failed VaxGen vaccine has shown promise when used in combination with the Aventis vaccine in smaller experiments. More elaborate experiments are needed to prove whether the combination is effective, they say.
The National Institute of Allergy and Infectious Disease, the NIH branch managing the test, issued a sharp rebuttal Thursday, declaring “no evidentiary data is provided (by critics) to support the prediction and assertions.”
Government officials said positive results from two earlier human tests gave them a scientific reason to proceed.
“That’s why you need the trial,” said Dr. John McNeil of the U.S. Army Medical Research and Material Command. “I get discouraged when nothing is done.”
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