International drug company Merck has halted trials on an HIV vaccine that was regarded as one of the most promising in the fight against Aids.
In trials, the vaccine failed to prevent HIV infections among volunteers who were at risk of catching the virus, including gay men and sex workers.
It was a high-profile failure in the daunting quest to develop a vaccine to prevent AIDS. Merck’s vaccine was the farthest along, considered the most promising and was closely watched by experts in the field.
Officials at the company, based in Whitehouse Station, N.J., said 24 of 741 volunteers who got the vaccine in one segment of the experiment later became infected with HIV, the virus that causes AIDS. In a comparison group of volunteers who got dummy shots, 21 of 762 participants also became infected.
“It’s very disappointing news,” said Keith Gottesdiener, head of Merck’s clinical infectious disease and vaccine research group. “A major effort to develop a vaccine for HIV really did not deliver on the promise.”
In a statement, the NIH said a data safety monitoring board, reviewing interim results, found the vaccine did not prevent HIV infection. Nor did it limit severity of the disease “in those who become infected with HIV as a result of their own behaviors that exposed them to the virus” — another goal of the study.