Experimental NNRTI-Based Microbicide Gel Prevents HIV Infection in Monkeys

An experimental vaginal microbicide applied daily protected female monkeys against simian HIV (SHIV) infection, even hours after application, according to the authors of a new study.

The gel combines zinc acetate and micromolar doses of MIV-150, a novel non-nucleoside reverse transcriptase inhibitor. Researchers tried using a gel containing each ingredient by itself, but they found the combination provided the best protection against SHIV.

The combination gel "afforded full protection (21 of 21 animals) for up to 24 hours after two weeks of daily application," wrote Melissa Robbiani, of the Population Council, and colleagues. The council led the study and holds a license to MIV-150, which was developed by Sweden-based Medivir.

The small dose of active drug in the gel might boost its safety profile and keep it cheap, the Population Council noted. The zinc acetate is meant to help prevent herpes, but that benefit was not tested in this trial. It also does not prevent pregnancy, though the researchers are working on a combination gel or ring that could be contraceptive.

"Just the idea of having a product that a woman could use to address the issue of unplanned pregnancy and [STDs] as well, that would be an enormous benefit to women," said Bethany Young Holt, a microbicide expert and director of the Coalition Advancing Multipurpose Innovations, a women's health research and advocacy group.

In addition to the Population Council, the National Cancer Institute and other labs helped test the gel.

The study, "An Antiretroviral/Zinc Combination Gel Provides 24 Hours of Complete Protection Against Vaginal SHIV Infection in Macaques," was published in the open-access Public Library of Science-ONE (2011;6(1):e15835).

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