Rationale: The overall rationale for all microbicide trials is to identify products that could be used vaginally or rectally to help reduce the user's risk of HIV infection. These candidates could be formulated in many ways including as gels, suppositories, creams, and vaginal rings.
BufferGel was designed to maintain normal vaginal acidity in the presence of semen. Semen reduces the acidity of the vagina and a lower vaginal pH may help inactivate HIV. (Studies have shown that HIV is inactivated below a pH of 4 to 5.8.) PRO 2000 is an HIV entry inhibitor, which means it's meant to block cellular receptors of target cells, so that HIV would be unable to attach to and infect them.
Study question(s): This study evaluated the safety and effectiveness of two vaginal microbicides in preventing the transmission of HIV. The study also evaluated the effectiveness of these gels in preventing other common sexually transmitted infections (STIs).
Participants: 3,220 HIV-negative women
Countries: Malawi, South Africa, US, Zambia, Zimbabwe
Trial sponsors and collaborators: Indevus, ReProtect, US National Institutes of Health (NIH)
When were results released? Results were announced February 2009. There were fewer infections in women using PRO 2000 than in women using the placebo gel, but this difference was not statistically significant. There was no evidence of benefit in women who used BufferGel.
To learn more visit:
http://www.mtnstopshiv.org/news/studies/hptn035/backgrounder
http://www.retroconference.org/2009/Abstracts/36659.htm