The first anti-HIV gel to use a drug known to stop the virus from replicating has been shown to be safe in early-stage clinical trials.
The results, which will appear in the journal AIDS on 28 February, opened the way for a larger safety study now taking place in New York, United States, and Pune, India.
So far, however, the research gives no indication of whether the gel, which contains the anti-HIV drug tenofovir, will ultimately protect from infection with HIV. Tenofovir is made by Gilead Sciences and sold under the brand name Viread.
The researchers led by Kenneth Mayer of Brown University in Providence, United States, are trying to use the drug to develop a gel that women could apply to their vaginas before sex.
As tenofovir is known to halt stop HIV from replicating, the researchers think the gel could prevent the virus from surviving in the body long enough to cause infection.
The 84 women in the initial clinical trial applied the gel up to twice daily and suffered no major side effects, apart from one who had severe abdominal cramping.
Mayer's team found that small amounts of tenofovir were absorbed into the blood after the women applied the gel.
Robin Shattock, professor of molecular infection at St George’s Medical School in London, United Kingdom, says future studies need to assess whether this could cause HIV to become resistant to the drug in women using the gel without knowing they already had the virus.
Shattock told SciDev.Net the results were "interesting but perhaps not groundbreaking".
Gels and creams applied to the genitals to protect from HIV infection are known as microbicides.
None is currently available for sale, though 20 are being tested in clinical trials.
Four of these have passed safety tests and are now in advanced trials to determine whether or not they protect from infection. Most act as a barrier, preventing the virus from entering cells.