Brief Report: Dapivirine Ring HIV-1 Prevention Effectiveness for Women Engaged in Vaginal and Anal Intercourse: Insights From Mathematical Modeling.

BACKGROUND: The dapivirine vaginal ring reduces the risk of HIV-1 acquisition in acts of vaginal intercourse (VI), and although it does not offer HIV-1 protection in acts of anal intercourse (AI), it may provide some overall risk reduction for women for whom most sex acts are vaginal. We estimated the protective effect of the ring among women with high ring adherence engaged in both VI and AI. METHODS: We developed a microsimulation model using data from the MTN-020/ASPIRE trial. Among women who reported any AI, we estimated the proportion of all sex acts that were AI. Model scenarios varied this proportion among women engaged in both VI and AI from 5% to 30%, including the trial-observed median proportion of 6.3% of all acts being AI. In primary analyses, dapivirine ring efficacy was model-calibrated at 70% for vaginal exposures and assumed to be 0% for anal exposures. RESULTS: Among highly adherent women for whom 6.3% of sex acts were AI, the ring reduced HIV-1 risk by 53% (interquartile range: 44, 60), with a decline to 26% (interquartile range: 16, 36) among women for whom 30% of acts were AI. Ring effectiveness was less than 40% among women for whom AI accounted for greater than 16% of all sex acts, although this represented less than 5% of all women in the ASPIRE trial. CONCLUSIONS: For most women, including those who engage in AI, because most HIV-1 risk occurs in acts of vaginal sex, the dapivirine vaginal ring can provide important HIV-1 protection.

Contraceptive Use and Pregnancy Incidence Among Women Participating in an HIV Prevention Trial.

BACKGROUND: Recent HIV prevention trials required use of effective contraceptive methods to fulfill eligibility for enrollment. We compared pregnancy rates in a subset of participants enrolled in the Microbicide Trials Network protocol (MTN-003), a randomized trial of chemoprophylaxis to prevent HIV acquisition among women aged 18-45 years who initiated depot medroxyprogesterone acetate (DMPA) or combined oral contraceptives (COCs) at enrollment, relative to those already using DMPA or COCs. METHODS: Data were analyzed from MTN-003 participants from Uganda. Before enrollment, information on contraceptive type and initiation date was obtained. Urine pregnancy tests were performed at monthly follow-up visits. Cox proportional hazards models were used to compare pregnancy incidence among new users (initiated ≤60 days before enrollment) and established users (initiated >60 days before enrollment). RESULTS: Of 322 women enrolled, 296 were COC or DMPA users, 82 (28%) were new users, and 214 (72%) were established users. Pregnancy incidence was higher among new contraceptive users compared to established users (20.70% vs. 10.55%; adjusted hazard ratio [HR] = 1.66; 95% confidence interval [95% CI] 0.93-2.96). Among DMPA users, pregnancy incidence was 10.20% in new users versus 3.48% in established users (HR = 2.56; 95% CI 0.86-7.65). Among new COC users, pregnancy incidence was 42.67% in new users versus 23.67% in established COC users (adjusted HR = 1.74; 95% CI 0.87-3.48). CONCLUSIONS: New contraceptive users, regardless of method, at the Uganda MTN-003 site had an increased pregnancy risk compared to established users, which may be due to contraceptive initiation primarily for trial eligibility. New users may benefit from intensive contraceptive counseling and additional contraceptive options, including longer acting reversible contraceptives.

Differences in Cumulative Exposure and Adherence to Tenofovir in the VOICE, iPrEx OLE, and PrEP Demo Studies as Determined via Hair Concentrations.

Pre-exposure prophylaxis (PrEP) with oral tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) prevented HIV acquisition among men and women in several trials and is broadly recommended. In the VOICE and FEM-PrEP trials, however, TDF/FTC-based PrEP did not prevent HIV acquisition among women in eastern and southern Africa. Tenofovir was detected in plasma, reflecting exposure and adherence in recent days, in fewer than one-third of participants. Drug concentrations in hair, which represent cumulative exposure and adherence over weeks to months, have never previously been examined among women on PrEP. We compared tenofovir hair concentrations among women assigned to oral TDF/FTC in the VOICE trial to those among men and transgender women enrolled in 2 open-label PrEP studies, the iPrEx open-label extension (OLE) study and the U.S. PrEP Demonstration Project (PrEP Demo). Tenofovir hair concentrations were detectable in 55% of person-visits in VOICE, 75% of person-visits in iPrEx OLE (p = .006), and 98% of person-visits in PrEP Demo (p < .001). Median tenofovir hair concentrations corresponded to an estimated 0.2, 2.9, and 6.0 TDF/FTC doses taken per week in the three studies, respectively. In VOICE, combining tenofovir concentration data from plasma and hair suggested inconsistent, low-level product use. Incorporation of both short- and long-term adherence measures may allow for an improved understanding of patterns of drug-taking among women during global PrEP roll-out.

Bone Mineral Density Changes Among Young, Healthy African Women Receiving Oral Tenofovir for HIV Preexposure Prophylaxis.

BACKGROUND: Limited data exist on effect of tenofovir disoproxil fumarate (TDF) when used for preexposure prophylaxis (PrEP) on bone mineral density (BMD) in HIV-negative women. We evaluated the effect of daily oral TDF and emtricitabine/TDF compared with placebo on BMD among women enrolled in an HIV-1 PrEP trial. METHODS: HIV-uninfected women in Uganda and Zimbabwe had BMD measurements of lumbar spine (LS) and total hip (TH) by dual-energy x-ray absorptiometry at baseline and every 24 weeks for 48 weeks of active treatment and for 48 weeks after discontinuation of study medication. Plasma tenofovir levels were assessed every 12 weeks for the first 48 weeks. RESULTS: Of 518 women enrolled, 432 had dual-energy x-ray absorptiometry results at baseline and week 48. In the primary analysis, no significant differences in percent BMD change in hip or spine between arms observed, likely because of low product adherence. Among the subset with tenofovir detection in 75%-100% of plasma samples, the mean percent BMD change from baseline to week 48 in the LS was 1.4% lower for TDF or emtricitabine/TDF recipients than for placebo (P = 0.002) and TH BMD was 0.9% lower (P = 0.018). BMD changes from end of active treatment to 48 weeks were significantly greater in the active arm participants compared with placebo participants with a net difference of approximately +0.9% at the LS (P = 0.007) and +0.7% (P = 0.003) at the TH. CONCLUSIONS: TDF-containing oral PrEP resulted in small but significant reversible decreases in hip and spine BMD among young African women.