A human test of the U.S. government’s experimental AIDS vaccine, similar to a failed Merck & Co. product, was canceled after a top scientist determined it was unlikely to give useful results.
Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in Bethesda, Md., said Thursday that he was unwilling to contribute the resources needed for the trial. The test was to include about 3,000 people and was originally planned to enroll as many as 8,000.
Fauci went against the recommendation of an advisory panel that voted May 30 in favor of conducting the test in some form. He said he would consider a smaller trial.
The government’s vaccine is intended to stimulate immune cells to reduce or eliminate levels of HIV, the AIDS virus, in the blood.
“Given the fact that there are not a lot of leads on an AIDS vaccine, I’m not willing to entirely shelve the concept,” Fauci said in a phone interview.
Merck, based in Whitehouse Station, N.J., developed a vaccine called Ad5, which was also intended to lower the amount of virus in the bloodstream. An international test of the vaccine in about 3,000 people was halted in September when 49 HIV infections occurred among those who received it, while just 33 who got placebo vaccinations caught HIV. That suggested the vaccine may have inadvertently increased HIV risk.
The failure of the Merck vaccine shows that more studies of the interaction between the human immune system and HIV are needed to design effective prevention, Fauci said.
AIDS activists were disappointed but understanding.
“This in no way signals the end of the search for an AIDS vaccine,” said Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition in New York. “This has to do with the investigation of this candidate.”
