Antiretroviral therapy and vaginally administered contraceptive hormones: a three-arm, pharmacokinetic study

This study is registered with ClinicalTrials.gov, number NCT01903031.FindingsBetween Dec 30, 2014, and Sept 12, 2016, we enrolled 84 participants in the study; ten participants were excluded from the primary hormone analysis. 74 participants met the primary endpoint: 25 in the control group, 25 in the efavirenz group, and 24 in the atazanavir group. On day 21 of intravaginal ring use, participants receiving efavirenz had 79% lower etonogestrel (GMR 0·21, 90% CI 0·16–0·28; p<0·0001) and 59% lower ethinylestradiol (0·41, 0·32–0·52; p<0·0001) concentrations compared with the control group. By contrast, participants receiving ritonavir-boosted atazanavir had 71% higher etonogestrel (1·71, 1·37–2·14; p<0·0001), yet 38% lower ethinylestradiol (0·62, 0·49–0·79; p=0·0037) compared with the control group. The AUC0–8 h of efavirenz or atazanavir did not differ between the groups.InterpretationHormone exposure was significantly lower when an intravaginal ring contraceptive was combined with efavirenz-based ART. Further studies designed to examine pharmacodynamic endpoints, such as ovulation, when intravaginal ring hormones are combined with efavirenz are warranted.FundingNational Institutes of Health, through the AIDS Clinical Trials Group and the International Maternal Pediatric Adolescent AIDS Clinical Trials Network, National Institute of Allergy and Infectious Diseases, Eunice Kennedy Shriver National Institute of Child Health and Human Developm...
Source: The Lancet HIV - Category: Infectious Diseases Source Type: research