Topical Microbicides in HIV Prevention: State of the Promise

Abstract

HIV topical microbicides are products with anti-HIV activity, generally incorporating a direct-acting antiretroviral agent, that when applied to the vagina or rectum have the potential to prevent the sexual acquisition of HIV in women and men. Topical microbicides may meet the prevention needs of individuals and groups for whom oral daily forms of pre-exposure prophylaxis (PrEP) have not been acceptable. Microbicides can provide personal control over HIV prevention and offer the possibility of discreet use, qualities that may be particularly important for receptive partners in sexual relationships such as women and transgender women and men, who together account for the clear majority of new HIV infections worldwide. Although the promise of such a product emerged nearly three decades ago, proof of concept has been demonstrated only within the last decade. A robust pipeline of microbicidal gels, films, inserts, and rings has been evaluated in multiple studies among at-risk women and men, and refinement of products for ease of use, reversibility, and high safety is the priority for the field.

Keywords: HIV; HIV prevention; dapivirine vaginal ring; microbicide.

Figure 1.. MTN-042 design

MTN-042 (https://mtnstopshiv.org/research/studies/mtn-042) is a planned open-label, multi-site, randomized trial of safety and pharmacokinetics of the dapivirine vaginal ring versus FTC/TDF oral PrEP (2:1 assignment) when used during pregnancy. Approximately 750 women aged 18–45 years who have an uncomplicated singleton pregnancy will be enrolled, in sequential cohorts, starting in later pregnancy and, if safety is demonstrated, moving earlier.

Figure 2.

Topical Microbicides as a Choice