Microbicides for HIV

Abstract

Microbicides are chemical entities that can be incorporated in gels, films, tablets or rings for application to the vagina or rectum to prevent the transmission of HIV and other sexually transmitted infections. Leading Australian microbicide efforts include the development of a dendrimer nanoparticle with broad-spectrum activity against HIV, HSV and HPV, and a natural factor produced by lactobacilli in the healthy female genital tract. Clinical trials have revealed that nonspecific agents such as nonoxynol-9 and moderately specific linear polyanions lack efficacy in preventing male to female HIV transmission. In contrast, the CAPRISA 004 study demonstrates that a gel containing an antiretroviral agent, 1% tenofovir, provides women with 39% protection against HIV infection. While this proof of concept study is arguably one of the most encouraging results seen in the HIV prevention field, efficacy and adherence could be improved by developing combination microbicides and coitally independent dosing strategies, respectively.