In a major setback for AIDS prevention research, a clinical trial of a new vaginal gel supposed to reduce HIV infections has been suspended after studies showed it to be ineffective.
Researchers from the Microbicide Trials Network, set up by the US National Institutes of Health (NIH), expressed surprise at the outcome as a previous study on a gel containing the drug tenofovir had shown encouraging results.
Researchers are striving to produce a gel or a pill that protects women against HIV infection but still allows them to get pregnant so it can be used in sub-Saharan Africa and other places where condom use can be a problem.
A first trial by the Centre for the AIDS Programme of Research in South Africa (CAPRISA) showed reduced HIV infections in 39 percent of women treated with the tenofivir gel, and in 54 percent of those who used it regularly.
Those results, published in 2010, raised hopes that a new gel could slow the transmission of HIV/AIDS and finally provide women with a groundbreaking means of protecting themselves.
Observers had hoped VOICE (Vaginal and Oral Interventions to Control the Epidemic), a trial started in September 2009 and conducted with the help of 5,000 women in South Africa, Uganda and Zimbabwe, would back those findings.
An interim review of VOICE by an independent data and safety monitoring board, however, determined that the tenofovir gel was even less effective than a placebo. Part of the research has now been cancelled.