Switch to long-acting cabotegravir and rilpivirine in virologically suppressed adults with HIV in Africa (CARES): week 48 results from a randomised, multicentre, open-label, non-inferiority trial.

BACKGROUND: Long-acting injectable cabotegravir and rilpivirine is licensed for individualised treatment of HIV-1 infection in resource-rich settings. Additional evidence is required to support use in African treatment programmes where demographic factors, viral subtypes, previous treatment, and delivery and monitoring approaches differ. The aim of this study was to determine whether switching to long-acting therapy with injections every 8 weeks is non-inferior to daily oral therapy in Africa. METHODS: CARES is a randomised, open-label, non-inferiority trial being conducted at eight sites in Uganda, Kenya, and South Africa. Participants with HIV viral load below 50 copies per mL on oral antiretroviral therapy and no history of virological failure were randomly assigned (1:1; web-based, permuted blocks) to receive cabotegravir (600 mg) and rilpivirine (900 mg) by intramuscular injection every 8 weeks, or to continue oral therapy. Viral load was monitored every 24 weeks. The primary outcome was week 48 viral load below 50 copies per mL, assessed with the Food and Drug Administration snapshot algorithm (non-inferiority margin 10 percentage points) in the intention-to-treat exposed population. This trial is registered with the Pan African Clinical Trials Registry (202104874490818) and is ongoing up to 96 weeks. FINDINGS: Between Sept 1, 2021, and Aug 31, 2022, we enrolled 512 participants (295 [58%] female; 380 [74%] previous non-nucleoside reverse transcriptase inhibitor exposure). Week 48 viral load was below 50 copies per mL in 246 (96%) of 255 participants in the long-acting therapy group and 250 (97%) of 257 in the oral therapy group (difference -0·8 percentage points; 95% CI -3·7 to 2·3), demonstrating non-inferiority (confirmed in per-protocol analysis). Two participants had virological failure in the long-acting therapy group, both with drug resistance; none had virological failure in the oral therapy group. Adverse events of grade 3 or greater severity occurred in 24 (9%) participants on long-acting therapy and ten (4%) on oral therapy; one participant discontinued long-acting therapy (for injection-site reaction). INTERPRETATION: Long-acting therapy had non-inferior efficacy compared with oral therapy, with a good safety profile, and can be considered for African treatment programmes. FUNDING: Janssen.

Acceptability of the dapivirine vaginal ring for HIV-1 prevention among women reporting engagement in transactional sex.

We assessed if acceptability of the dapivirine vaginal ring for HIV prevention differed among the subgroup of women who reported engaging in transactional sex prior to enrollment in MTN-020/ASPIRE (phase III trial in Malawi, South Africa, Uganda, and Zimbabwe, 2012-2015; n = 2629). Transactional sex was defined as receipt of money, goods, gifts, drugs, or shelter in exchange for sex in the past year. Dimensions of acceptability included: ease of use and physical sensation in situ, impacts on sex, partner's opinion, and likelihood of future use. We used Poisson regression models with robust standard errors to compare risk of acceptability challenges by baseline history of transactional sex. At product discontinuation, women exchanging sex found the ring comfortable (90%), easy to insert (92%) and nearly all (96%) were likely to use the ring in the future. Women who had exchanged sex were more likely to report feeling the ring during sex (ARR 1.43, 95% CI: 1.09, 1.89; p = 0.01) and slightly more likely to mind wearing the ring during menses (ARR 1.22, 95% CI: 1.01, 1,46; p = 0.04) and during sex (ARR 1.22, 95% CI: 1.02, 1.45; p = 0.03). Messaging and counseling should include enhanced support for use during sex and menses to support optimal use.

High monoclonal neutralization titers reduced breakthrough HIV-1 viral loads in the Antibody Mediated Prevention trials.

The Antibody Mediated Prevention (AMP) trials (NCT02716675 and NCT02568215) demonstrated that passive administration of the broadly neutralizing monoclonal antibody VRC01 could prevent some HIV-1 acquisition events. Here, we use mathematical modeling in a post hoc analysis to demonstrate that VRC01 influenced viral loads in AMP participants who acquired HIV. Instantaneous inhibitory potential (IIP), which integrates VRC01 serum concentration and VRC01 sensitivity of acquired viruses in terms of both IC50 and IC80, follows a dose-response relationship with first positive viral load (p = 0.03), which is particularly strong above a threshold of IIP = 1.6 (r = -0.6, p = 2e-4). Mathematical modeling reveals that VRC01 activity predicted from in vitro IC80s and serum VRC01 concentrations overestimates in vivo neutralization by 600-fold (95% CI: 300-1200). The trained model projects that even if future therapeutic HIV trials of combination monoclonal antibodies do not always prevent acquisition, reductions in viremia and reservoir size could be expected.

Patterns of Adherence to a Dapivirine Vaginal Ring for HIV-1 Prevention Among South African Women in a Phase III Randomized Controlled Trial.

BACKGROUND: Persistent use of HIV prevention methods can be a challenge, particularly for some younger women. The long-acting, discreet, woman-centric dapivirine vaginal ring offers promise as a prevention method with less user burden, which could support continued use. We assessed dapivirine vaginal ring use to understand adherence patterns and identify characteristics influencing patterns. SETTING: Participants enrolled in South Africa in the MTN-020/ASPIRE randomized placebo-controlled trial. METHODS: We used group-based trajectory modeling to identify clusters of participants with similar longitudinal patterns of adherence in the last year of participation and potential predictors of group membership. Women with at least 1 year of follow-up were included (n = 626). RESULTS: Five adherence patterns were identified: (1) consistently high, 34%, (2) consistently moderate, 34%, (3) consistently low, 16%, (4) decreasing, 9%, and (5) increasing, 7%. Women younger than 22 years [adjusted odds ratio (AOR) 1.8, 95% confidence interval (CI): 1.0 to 3.0], using an intrauterine device (AOR 3.3, 95% CI: 1.4 to 7.8) or oral contraceptives (AOR 3.9, 95% CI: 1.7 to 8.9), experiencing menses (AOR 1.8, 95% CI: 1.1 to 3.0), and who reported inconsistent condom use (AOR 1.8, 95% CI: 1.0 to 3.3) were more likely to be classified as consistently low compared to consistently high (referent). CONCLUSIONS: Most South African women successfully persisted with a moderate or high level of use. Encouraging ring replacement with completion of menses may help to decrease concerns about hygiene and improve persistence. Associations between contraception and persistent low adherence suggest efforts may be needed to ensure contraceptive method choice does not interfere with ring use.

Prevalent human papillomavirus infection increases the risk of HIV acquisition in African women: advancing the argument for human papillomavirus immunization.

OBJECTIVE: Vaccine-preventable human papillomavirus (HPV) infection is common, especially in sub-Saharan Africa where HIV risk is also high. However, unlike other sexually transmitted infections (STIs), HPV's role in HIV acquisition is unclear. We evaluated this relationship using data from MTN-003, a clinical trial of HIV chemoprophylaxis among cisgender women in sub-Saharan Africa. DESIGN: A case-control study. METHODS: We matched 138 women who acquired HIV (cases) to 412 HIV-negative controls. Cervicovaginal swabs collected within 6 months before HIV seroconversion were tested for HPV DNA. We estimated the associations between carcinogenic (high-risk) and low-risk HPV types and types targeted by HPV vaccines and HIV acquisition, using conditional logistic regression models adjusted for time-varying sexual behaviors and other STIs. RESULTS: Mean age was 23 (±4) years. Any, high-risk and low-risk HPV was detected in 84, 74 and 66% of cases, and 65, 55 and 48% of controls. Infection with at least two HPV types was common in cases (67%) and controls (49%), as was infection with nonavalent vaccine-targeted types (60 and 42%). HIV acquisition increased with any [adjusted odds ratio (aOR) 2.5, 95% confidence interval (95% CI) 1.3-4.7], high-risk (aOR 2.6, 95% CI 1.5-4.6) and low-risk (aOR 1.8, 95% CI 1.1-2.9) HPV. Each additional type detected increased HIV risk by 20% (aOR 1.2, 95% CI 1.1-1.4). HIV acquisition was associated with HPV types targeted by the nonavalent (aOR 2.1, 95% CI 1.3-3.6) and quadrivalent vaccines (aOR 1.9, 95% CI 1.1-3.2). CONCLUSION: HPV infection is associated with HIV acquisition in sub-Saharan African women. In addition to preventing HPV-associated cancers, increasing HPV vaccination coverage could potentially reduce HIV incidence.

Infusion Reactions After Receiving the Broadly Neutralizing Antibody VRC01 or Placebo to Reduce HIV-1 Acquisition: Results From the Phase 2b Antibody-Mediated Prevention Randomized Trials.

BACKGROUND: The antibody-mediated prevention (AMP) studies (HVTN 703/HPTN 081 and HVTN 704/HPTN 085) are harmonized phase 2b trials to assess HIV prevention efficacy and safety of intravenous infusion of anti-gp120 broadly neutralizing antibody VRC01. Antibodies for other indications can elicit infusion-related reactions (IRRs), often requiring premedication and limiting their application. We report on AMP study IRRs. METHODS: From 2016 to 2018, 2699 HIV-uninfected, at-risk men and transgender adults in the Americas and Switzerland (704/085) and 1924 at-risk heterosexual women in sub-Saharan Africa (703/081) were randomized 1:1:1 to VRC01 10 mg/kg, 30 mg/kg, or placebo. Participants received infusions every 8 weeks (n = 10/participant) over 72 weeks, with 104 weeks of follow-up. Safety assessments were conducted before and after infusion and at noninfusion visits. A total of 40,674 infusions were administered. RESULTS: Forty-seven participants (1.7%) experienced 49 IRRs in 704/085; 93 (4.8%) experienced 111 IRRs in 703/081 (P < 0.001). IRRs occurred more frequently in VRC01 than placebo recipients in 703/081 (P < 0.001). IRRs were associated with atopic history (P = 0.046) and with younger age (P = 0.023) in 703/081. Four clinical phenotypes of IRRs were observed: urticaria, dyspnea, dyspnea with rash, and "other." Urticaria was most prevalent, occurring in 25 (0.9%) participants in 704/085 and 41 (2.1%) participants in 703/081. Most IRRs occurred with the initial infusion and incidence diminished through the last infusion. All reactions were managed successfully without sequelae. CONCLUSIONS: IRRs in the AMP studies were uncommon, typically mild or moderate, successfully managed at the research clinic, and resolved without sequelae. Analysis is ongoing to explore potential IRR mechanisms.

The Influence of Perceived Dapivirine Vaginal Ring Effectiveness on Social Disclosure and Ring Adherence.

We analyzed data from 1428 users of the dapivirine vaginal ring, who participated in the MTN-020/ASPIRE phase III trial and subsequent open-label extension MTN-025/HOPE trial, to examine relationships between perceived ring protection, social disclosures, and self-reported ring adherence. In HOPE, 77% perceived the ring to be highly effective, and this view was associated with speaking: (a) to a greater number of people about the study, (b) with other participants, (c) to more people who were in favor of the ring, and (d) to more people whose opinions were valued. Reported adherence was not directly associated with perceived protection but was associated with disclosing to someone who was in favor of the ring. These findings suggest the importance of women's internalized ideas about the protective benefits of the DVR in sharing information about the ring and the importance of social support on adherence.

Safety, uptake, and use of a dapivirine vaginal ring for HIV-1 prevention in African women (HOPE): an open-label, extension study.

BACKGROUND: Two phase 3 clinical trials showed that use of a monthly vaginal ring containing 25 mg dapivirine was well tolerated and reduced HIV-1 incidence in women by approximately 30% compared with placebo. We aimed to evaluate use and safety of the dapivirine vaginal ring (DVR) in open-label settings with high background rates of HIV-1 infection, an important step for future implementation. METHODS: We did a phase 3B open-label extension trial of the DVR (MTN-025/HIV Open-label Prevention Extension [HOPE]). Women who were HIV-1-negative and had participated in the MTN-020/ASPIRE phase 3 trial were offered 12 months of access to the DVR at 14 clinical research centres in Malawi, South Africa, Uganda, and Zimbabwe. At each visit (monthly for 3 months, then once every 3 months), women chose whether or not to accept the offer of the ring. Used, returned rings were tested for residual amounts of dapivirine as a surrogate marker for adherence. HIV-1 serological testing was done at each visit. Dapivirine amounts in returned rings and HIV-1 incidence were compared with data from the ASPIRE trial, and safety was assessed. This study is registered with ClinicalTrials.gov, NCT02858037. FINDINGS: Between July 16, 2016, and Oct 10, 2018, of 1756 women assessed for eligibility, 1456 were enrolled and participated in the study. Median age was 31 years (IQR 27-37). At baseline, 1342 (92·2%) women chose to take the DVR; ring acceptance was more than 79% at each visit up until 12 months and 936 (73·2%) of 1279 chose to take the ring at all visits. 12 530 (89·3%) of 14 034 returned rings had residual dapivirine amounts consistent with some use during the previous month (>0·9 mg released) and the mean dapivirine amount released was greater than in the ASPIRE trial (by 0·21 mg; p<0·0001). HIV-1 incidence was 2·7 per 100 person-years (95% CI 1·9-3·8, 35 infections), compared with an expected incidence of 4·4 per 100 person-years (3·2-5·8) among a population matched on age, site, and presence of a sexually transmitted infection from the placebo group of ASPIRE. No serious adverse events or grade 3 or higher adverse events observed were assessed as related to the DVR. INTERPRETATION: High uptake and persistent use in this open-label extension study support the DVR as an HIV-1 prevention option for women. With an increasing number of HIV-1 prophylaxis choices on the horizon, these results suggest that the DVR will be an acceptable and practical option for women in Africa. FUNDING: The Microbicide Trials Network and the National Institute of Allergy and Infectious Diseases, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, and the National Institute of Mental Health, all components of the US National Institutes of Health.

Pharmacokinetics and predicted neutralisation coverage of VRC01 in HIV-uninfected participants of the Antibody Mediated Prevention (AMP) trials.

The phase 2b AMP trials are testing whether the broadly neutralising antibody VRC01 prevents HIV-1 infection in two cohorts: women in sub-Saharan Africa, and men and transgender persons who have sex with men (MSM/TG) in the Americas and Switzerland. We used nonlinear mixed effects modelling of longitudinal serum VRC01 concentrations to characterise pharmacokinetics and predict HIV-1 neutralisation coverage. We found that body weight significantly influenced clearance, and that the mean peripheral volume of distribution, steady state volume of distribution, elimination half-life, and accumulation ratio were significantly higher in MSM/TG than in women. Neutralisation coverage was predicted to be higher in the first (versus second) half of a given 8-week infusion interval, and appeared to be higher in MSM/TG than in women overall. Study cohort differences in pharmacokinetics and neutralisation coverage provide insights for interpreting the AMP results and for investigating how VRC01 concentration and neutralisation correlate with HIV incidence.

Elevated Risk of Bacterial Vaginosis Among Users of the Copper Intrauterine Device: A Prospective Longitudinal Cohort Study.

BACKGROUND: Limited evidence suggests that the nonhormonal contraceptive copper intrauterine device (Cu-IUD) may increase bacterial vaginosis (BV) risk, possibly due to increased volume and duration of menses, a common side effect of Cu-IUD use. Although increases in bleeding typically resolve within 6-12 months following initiation, evaluations of the association between Cu-IUD and BV have not included more than 6 months of follow-up. METHODS: This secondary analysis of a human immunodeficiency virus type 1 prevention trial included 2585 African women ages 18-45 followed for up to 33 months. Women reported contraceptive use each month. BV was evaluated by Nugent score in 6-monthly intervals and, if clinically indicated, by Amsel criteria. Andersen-Gill proportional hazards models were used to (1) evaluate BV risk among Cu-IUD users relative to women using no/another nonhormonal contraceptive and (2) test changes in BV frequency before, while using, and following Cu-IUD discontinuation. RESULTS: BV frequency was highest among Cu-IUD users at 153.6 episodes per 100 person-years (95% confidence interval [CI]: 145.2, 162.4). In adjusted models, Cu-IUD users experienced 1.28-fold (95% CI: 1.12, 1.46) higher BV risk relative to women using no/another nonhormonal contraception. Compared to the 6 months prior to initiation, BV risk was 1.52-fold (95% CI: 1.16, 2.00) higher in the first 6 months of Cu-IUD use and remained elevated over 18 months of use (P < .05). Among women who discontinued Cu-IUD, BV frequency was similar to pre-initiation rates within 1 year. CONCLUSIONS: Cu-IUD users experienced elevated BV risk that persisted throughout use. Women and their providers may wish to consider BV risk when discussing contraceptive options.

Use of the dapivirine vaginal ring and effect on cervical cytology abnormalities.

OBJECTIVE: We aimed to determine if the dapivirine vaginal ring and the ring device alone (flexible silicone matrix polymer) was associated with the development of cervical cytology abnormalities. DESIGN: Secondary analysis comparing cervical cytology results between two randomized controlled microbicide trials (MTN-020/ASPIRE and MTN-003/VOICE). METHODS: Data from ASPIRE, a phase III, placebo-controlled trial of the dapivirine vaginal ring, were used in this analysis. Cervical cytology smears were evaluated at baseline and at the final visit with product use. We compared cytology results between women randomized to dapivirine versus placebo vaginal ring. We further assessed for the effect of the vaginal ring device on cervical cytology by comparing results with data from the oral placebo arm of VOICE, a prior HIV-1 prevention trial conducted in a similar population. RESULTS: Cervical cytology results for 2394 women from ASPIRE (1197 per study arm) were used in this analysis; median time between baseline and final visit with product use was 22.1 months. Cytology smear findings were comparable between dapivirine and placebo vaginal ring arms: at final visit, normal: 90.6 versus 91.5%, ASC-US//LSIL: 7.8 versus 7.4%, ASC-H/HSIL/AGC/AGC-favor neoplastic: 1.7 versus 1.1%, P = 0.44. Cytology data from VOICE had findings (normal: 87.8%, ASC-US/LSIL: 9.8%, ASC-H/HSIL/AGC/AGC-favor neoplastic: 2.4%) comparable with that of both dapivirine (P = 0.93) and placebo vaginal ring arms (P = 0.24). CONCLUSION: These findings indicate that neither use of the dapivirine vaginal ring nor the vaginal ring device alone, over a period of 2 years, is associated with development of cervical cytology abnormalities that could lead to precancerous or cancerous lesions.

Social harms in female-initiated HIV prevention method research: state of the evidence.

OBJECTIVES: Assessment of safety is an integral part of real-time monitoring in clinical trials. In HIV prevention research, safety of investigational products and trial participation has been expanded to include monitoring for 'social harms', generally defined as negative consequences of trial participation that may manifest in social, psychological, or physical ways. Further research on social harms within HIV prevention research is needed to understand the potential safety risks for women and advance the implementation of prevention methods in real-world contexts. METHODS: Secondary analysis of quantitative data from three randomized, double-blind, placebo-controlled trials of microbicide candidates in sub-Saharan Africa was conducted. Additionally, we assessed data from two prospective cohort studies that included participants who became HIV-positive or pregnant during parent trials. RESULTS: Social harms reporting was low across the largest and most recent microbicide studies. Social harm incidence per 100 person-years ranged from 1.10 (95% CI 0.78-1.52) to 3.25 (95% CI 2.83-3.74) in the phased trials. Reporting differed by dosing mechanism (e.g. vaginal gel, oral tablet, ring) and study, most likely as a function of measurement differences. Social harms were most frequently associated with male partners, rather than, for example, experiences of stigma in the community. CONCLUSION: Measurement and screening for social harms is an important component of conducting ethical research of novel HIV prevention methods. To date, social harm incidence reported in microbicide trials has been relatively low (<4% per 100 person-years), and the majority have been partner-related events. However, any incidence of social harm within the context of HIV prevention is important to capture and understand for the safety of individuals, and for the successful impact of prevention methods in a real-world context.

Impact of Partner-Related Social Harms on Women's Adherence to the Dapivirine Vaginal Ring During a Phase III Trial.

BACKGROUND: Long-acting female-initiated methods such as the dapivirine ring may give women greater agency in HIV-1 prevention. However, social harms, defined as nonmedical adverse consequences of study participation or dapivirine ring use, may reduce product adherence and consequently HIV-1 protection. METHODS: We assessed whether experiencing social harms from male partners was associated with lower adherence to the dapivirine ring in the MTN-020/ASPIRE trial. Reports of social harms were solicited quarterly. Low adherence was defined by plasma dapivirine levels ≤95 pg/mL or residual dapivirine levels in returned rings >23.5 mg. RESULTS: Among 2629 women enrolled in ASPIRE, 85 (3.2%) reported 87 social harms during a median follow-up of 1.6 years. Women were significantly more likely to have low adherence, measured by plasma dapivirine levels, at visits with a social harm in the past month than at visits where no social harm was reported (adjusted risk ratio 2.53, 95% confidence interval: 1.37 to 4.66, P = 0.003). There was no association for social harms reported ≥1 month prior, suggesting an acute, short-term effect. Women were significantly more likely to not return a ring at visits with a social harm reported (adjusted risk ratio 24.70, 95% confidence interval: 18.57 to 32.85, P < 0.001). In rings that were returned, social harms were not associated with residual dapivirine levels. CONCLUSIONS: Although social harms were uncommon (<5% of women with >1 year of use), participants reporting social harms by male partners had lower adherence to the dapivirine ring. Strategies to mitigate nonadherence to product use related to social harms should be evaluated in future studies of female-controlled HIV-1 prevention options.

Brief Report: Dapivirine Vaginal Ring Use Does Not Diminish the Effectiveness of Hormonal Contraception.

OBJECTIVE: To evaluate the potential for a clinically relevant drug-drug interaction with concomitant use of a dapivirine vaginal ring, a novel antiretroviral-based HIV-1 prevention strategy, and hormonal contraception by examining contraceptive efficacies with and without dapivirine ring use. DESIGN: A secondary analysis of women participating in MTN-020/ASPIRE, a randomized, double-blind, placebo-controlled trial of the dapivirine vaginal ring for HIV-1 prevention. METHODS: Use of a highly effective method of contraception was an eligibility criterion for study participation. Urine pregnancy tests were performed monthly. Pregnancy incidence by arm was calculated separately for each hormonal contraceptive method and compared using an Andersen-Gill proportional hazards model stratified by site and censored at HIV-1 infection. RESULTS: Of 2629 women enrolled, 2310 women returned for follow-up and reported using a hormonal contraceptive method at any point during study participation (1139 in the dapivirine arm and 1171 in the placebo arm). Pregnancy incidence in the dapivirine arm versus placebo among women using injectable depot medroxyprogesterone acetate was 0.43% vs. 0.54%, among women using injectable norethisterone enanthate was 1.15% vs. 0%, among women using hormonal implants was 0.22% vs. 0.69%, and among women using oral contraceptive pills was 32.26% vs. 28.01%. Pregnancy incidence did not differ by study arm for any of the hormonal contraceptive methods. CONCLUSIONS: Use of the dapivirine ring does not reduce the effectiveness of hormonal contraceptives for pregnancy prevention. Oral contraceptive pill use was associated with high pregnancy incidence, potentially because of poor pill adherence. Injectable and implantable methods were highly effective in preventing pregnancy.

Use of a Vaginal Ring Containing Dapivirine for HIV-1 Prevention in Women.

BACKGROUND: Antiretroviral medications that are used as prophylaxis can prevent acquisition of human immunodeficiency virus type 1 (HIV-1) infection. However, in clinical trials among African women, the incidence of HIV-1 infection was not reduced, probably because of low adherence. Longer-acting methods of drug delivery, such as vaginal rings, may simplify use of antiretroviral medications and provide HIV-1 protection. METHODS: We conducted a phase 3, randomized, double-blind, placebo-controlled trial of a monthly vaginal ring containing dapivirine, a non-nucleoside HIV-1 reverse-transcriptase inhibitor, involving women between the ages of 18 and 45 years in Malawi, South Africa, Uganda, and Zimbabwe. RESULTS: Among the 2629 women who were enrolled, 168 HIV-1 infections occurred: 71 in the dapivirine group and 97 in the placebo group (incidence, 3.3 and 4.5 per 100 person-years, respectively). The incidence of HIV-1 infection in the dapivirine group was lower by 27% (95% confidence interval [CI], 1 to 46; P=0.046) than that in the placebo group. In an analysis that excluded data from two sites that had reduced rates of retention and adherence, the incidence of HIV-1 infection in the dapivirine group was lower by 37% (95% CI, 12 to 56; P=0.007) than that in the placebo group. In a post hoc analysis, higher rates of HIV-1 protection were observed among women over the age of 21 years (56%; 95% CI, 31 to 71; P<0.001) but not among those 21 years of age or younger (-27%; 95% CI, -133 to 31; P=0.45), a difference that was correlated with reduced adherence. The rates of adverse medical events and antiretroviral resistance among women who acquired HIV-1 infection were similar in the two groups. CONCLUSIONS: A monthly vaginal ring containing dapivirine reduced the risk of HIV-1 infection among African women, with increased efficacy in subgroups with evidence of increased adherence. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01617096 .).