U.S. drops trial of one AIDS vaccine

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - U.S. AIDS researchers are dropping plans to test one experimental vaccine in people, saying the high-profile failure of a Merck and Co. vaccine last year shows the need to do quicker, more focused studies.

The National Institute of Allergy and Infectious Diseases, part of the government's National Institutes of Health, said on Thursday it was canceling the HIV vaccine study known as PAVE 100.

"However, NIAID believes the vaccine developed by its Vaccine Research Center (VRC) is scientifically intriguing and sufficiently different from previously tested HIV vaccines to consider testing it in a smaller, more focused clinical study," the institute said in a statement.

It is the first demonstration of a new approach being taken by federal vaccine developers after a trial called STEP showed last year that Merck's vaccine may have raised the risk of infection among certain men -- those who had pre-existing immune responses to the virus used in the vaccine and who were not circumcised.

The vaccine used a common virus known as an adenovirus to carry bits of the AIDS virus. "It didn't work, it wasn't beneficial and there were the issues of risk for people who were uncircumcised," NIAID director Dr. Anthony Fauci said in a telephone interview.

"I am entertaining a smaller, leaner, less-expensive trial," Fauci added.

The new vaccine being tested by the Partnership for AIDS Vaccine Evaluation, or PAVE, was designed to be given as three injections of HIV genetic material, followed with a final boost of adenovirus.

"I do believe that it is worthwhile pursuing this concept of a DNA vaccine, but I don't believe that we have enough information to warrant making that a large trial," Fauci said.  Continued...