WASHINGTON (AP) — The Food and Drug Administration has granted a California company permission to begin the largest test yet of a possible vaccine to prevent infection by the virus that causes AIDS.
There’s no guarantee the vaccine will work, and many U.S. scientists are highly skeptical because it’s based on a concept that the National Institutes of Health shelved in 1994.
But the three-year trial of VaxGen Inc.’s AIDSvax, which will include 5,000 American volunteers at high risk for catching the AIDS virus and 2,500 high-risk people in Thailand, should at least settle long debate about this approach.
An anti-AIDS vaccine would train the human immune system to ward off infection with HIV, the AIDS virus. Some 25 potential vaccines have been tried in people worldwide. Until now none has advanced to the larger-scale testing, known as a Phase III trial, allowed for AIDSvax.
VaxGen, the producer, is optimistic. It contends AIDSvax is an improved version of the controversial gp120 vaccine, because the company added another strain of HIV protection to the original shot.
Smaller tests of AIDSvax showed 99.5 percent of vaccinated people produced strong levels of antibodies, immune system cells that can target and kill infection, explained VaxGen chief operating officer Daniel T. Reiner.
Beginning the first Phase III trial of a possible vaccine “is a watershed event,” said Dr. Seth Berkley of the International AIDS Vaccine Initiative, a new nonprofit group pushing development of a vaccine.
By allowing large-scale testing, the FDA did not say that AIDSvax will work — just that it is safe enough to attempt.