HIV Researcher Cancels Clinical Trial

On July 17, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, scrapped plans for a large clinical trial of the government's most advanced HIV vaccine candidate to date. The vaccine, a two-shot injection, was designed to fight HIV infection a new way — by activating the body's cell-based immune responses rather than by relying on antibodies to HIV.

The trial that Fauci canceled last week was already a slimmed down version of the original 8,500-person study that government health officials had planned — until the Merck vaccine failed last fall. In a trial of 3,000 volunteers, Merck's vaccine appeared to increase risk of HIV infection, a phenomenon that researchers later attributed to the vaccine's delivery system — pieces of HIV were piggybacked onto a common cold virus and ferried to the body's immune cells. It turned out that the people who received the vaccine and who ended up with the highest rates of HIV infection following injection were also those who had high levels of antibodies to the cold virus, thus negating any immune-boosting effects of the vaccine.

Fauci says the decision doesn't spell the end for the cell-based approach — he just believes more basic work is necessary to understand how these approaches work. And conducting smaller, more focused trials help to do just that.