Experimental Microbicide Tenofovir Safe for Women To Use Daily, Study Finds
The experimental microbicide tenofovir is safe for women to use daily, according to results from clinical trials funded by NIH and conducted in three locations in the U.S. and India, though it is too early to tell if it actually prevents HIV infection, Reuters reports (Fox, Reuters, 2/25). Microbicides include a range of products -- such as gels, films and sponges -- that could help prevent the sexual transmission of HIV and other infections (Kaiser Daily HIV/AIDS Report, 2/6). A study released last week showed that the microbicide candidate Carraguard, though safe, was ineffective in preventing HIV transmission. Other candidates, including nonoxynol-9 and Ushercell, have been found to increase women's risk of HIV infection, according to Reuters (Reuters, 2/25).
The study -- presented at Microbicides 2008, the biannual international conference that began on Sunday in New Delhi, India -- was conducted from August 2006 to September 2007 at the National AIDS Research Institute in Pune, India; the Bronx-Lebanon Hospital Center; and at the University of Alabama-Birmingham, the Times of India reports. Tenofovir gel is a HIV-specific microbicide that is designed to prevent HIV from replicating when it comes in contact with uninfected T-cells (Sinha, Times of India, 2/23). The study involved 200 HIV-negative women of reproductive age who were asked to apply the gel either daily or before sexual intercourse for about six months. The women were asked to use condoms as well as the gel, AFP/Yahoo! News reports.
The study found no disruption of blood, liver or kidney function and found that women were willing to follow the treatment guidelines. According to the study, more than 90% of the participants said they would consider using the gel to prevent HIV transmission if it were approved. More than 80% of the participants followed the experimental regimen, the study found.
Sharon Hillier, lead investigator and director of reproductive infectious diseases at the University of Pittsburgh School of Medicine, said, "Based on what we have learned, we can proceed with greater confidence on a path that will answer whether tenofovir gel and other gels with HIV-specific compounds will be able to prevent sexual transmission of HIV in women when other approaches have failed to do so" (AFP/Yahoo! News, 2/25). Craig Hoesley of UAB said a "key message" of the results is that the "gel is safe to use and well-tolerated by HIV-negative women," adding, "This sets the stage for larger studies to see if tenofovir can prevent HIV infection" (Reuters, 2/25). According to the Times of India, a Phase II trial is under way among 1,000 women in South Africa to test the microbicide's effectiveness at preventing HIV transmission (Times of India, 2/23).
Development of Microbicides Top Priority for India, Health Minister Says
In related news, India's Health Minister Anbumani Ramadoss at the conference said the development of microbicides is a priority for India, the Press Trust of India reports. "At the moment, 50 experimental substances as possible vaginal microbicides are being examined and about a quarter of these agents are at various stages of human testing and four of these are in advanced states of clinical trials," Ramadoss said. He added that "women need a product that they can control and even use without their partners' consent or knowledge." Effective microbicides would offer an alternative method of protection for women, Ramadoss said (Press Trust of India, 2/24).