CROI 2017: Daily Oral PrEP Effective Even in Presence of Bacterial Vaginosis

Women with abnormal vaginal microbiota showed no difference in efficacy of daily oral PrEP compared to women with normal vaginal microbiota, according to data presented at the annual Conference on Retroviruses and Opportunistic Infections in Seattle.

The study aimed to determine if the efficacy of daily oral PrEP with tenofovir was reduced among women with bacterial vaginosis or other indicators of vaginal dysbiosis. The researchers used data from women in the Partners PrEP Study to assess PrEP efficacy. The Partners PrEP Study showed a high (80%) daily oral PrEP adherence and overall efficacy >70% in women.

The study included 1470 women with a median age of 33 years old, of which 24% had bacterial vaginosis at the time of enrollment. PrEP efficacy rates for HIV prevention were as follows: women with normal microbiota (77%), women with intermediate microbiota (73%), and women with bacterial vaginosis (63%). The results also indicated that efficacy was no different among women with detected versus undetected Gardnerella vaginalis/Bacteroides (69% efficacy versus 77%) and Lactobacillus (74% versus 70%).

Data from the CAPRISA study reported at the AIDS 2016 meeting suggested that the vaginal bacteria Gardenerella vaginalis, which predominates in the vagina when Lactobacillus is not dominant, absorbs the gel formulation of pre-exposure prophylaxis tenofovir, thereby reducing its availability in the genital tract to prevent HIV infection.

In this study, the researchers concluded that daily oral tenofovir-based PrEP efficacy was not affected by the prevalence of bacterial vaginosis, as long as the individual maintained high PrEP adherence.

Reference

Heffron R, McClelland RS, Balkus J, et al. Daily oral prep is effective among women with abnormal vaginal microbiota. Presented at: Conference on Retroviruses and Opportunistic Infections; Feb. 13-16, 2017; Seattle.