The US$62-billion Bill and Melinda Gates Foundation has poured money into microbicide research, because a woman “should never need her partner's permission to save her own life,” Bill Gates told the opening session of the XVIth International AIDS Conference in August.
Microbicides are applied to the vaginal or rectal surface before sex in order to prevent HIV infection. Microbicide research began in the early 1990s, but it did not receive a great deal of funding or attention until a few years ago after the establishment of the non-profit International Partnership for Microbicides in 2002 brought new energy to the field.
There are now 5 gels, which must be applied immediately before sex, in phase 3 clinical trials. The products in earlier stages of development use direct antiretroviral effects. For example, a gel form of the drug tenofovir is in phase 2 trials.
A long-term goal is to develop a formulation or device that allows for the slow release of microbicide over a period of days or months. However, researchers are concerned that limited clinical trial capacity in countries with high rates of HIV infection is hampering advances.