Jennifer E. Balkus

Weighing the gold in the gold standard: challenges in HIV prevention research.

Objective(s):Few HIV prevention interventions have been evaluated in randomized controlled trials (RCTs). We examined design, implementation, and contextual considerations that may limit detection of a positive or adverse effect in HIV prevention trials. Design:A systematic review of late phase RCTs for prevention of sexual transmission of HIV that randomly allocated intervention and comparison groups; evaluated interventions to prevent sexual transmission in nonpregnant populations; and reported HIV incidence as the primary or secondary outcome. Methods:PubMed/MEDLINE, other electronic databases, and electronic conference proceedings of recent HIV/AIDS-related conferences were searched to identify published or unpublished trials meeting the inclusion criteria. Descriptive, methodological, and contextual factors were abstracted from each trial. Results:The review included 37 HIV prevention RCTs reporting on 39 unique interventions. Only six RCTs, all evaluating biomedical interventions, demonstrated definitive effects on HIV incidence. Five of the six RCTs significantly reduced HIV infection: all three male circumcision trials, one trial of sexually transmitted infection treatment and care, and one vaccine trial. One microbicide trial of nonoxynol-9 gel produced adverse results. Lack of statistical power, poor adherence, and diluted versions of the intervention in comparison groups may have been important issues for the other trials that demonstrated ‘flat’ results. Conclusion:Almost 90% of HIV prevention trials had ‘flat’ results, which may be attributable to trial design and/or implementation. The HIV prevention community must not only examine evidence from significant RCTs, but must also examine flat trials and address design and implementation issues that limit detection of an effect.

Antiretroviral-Associated Toxicity Among HIV-1-Seropositive Pregnant Women in Mozambique Receiving Nevirapine-Based Regimens

Objective:To assess toxicities associated with highly active antiretroviral therapy (HAART) among HIV-1-infected pregnant women treated with nevirapine-based regimens according to Mozambican national guidelines. Study Design:Prospective cohort study. Methods:HIV-1-infected antiretroviral-naive pregnant women with CD4 counts ≤350 cells/μL were initiated on nevirapine, lamivudine, and stavudine or zidovudine and followed monthly. Severe hepatotoxicity was defined as aspartate aminotransferase (AST) or alanine aminotransferase (ALT) levels ≥5-fold the upper limit of normal. Analyses were stratified by baseline CD4 count (<250 vs. 250-350 cells/μL). Results:Among 146 pregnant women, 75 (52%) began nevirapine, lamivudine, and zidovudine and 71 (48%) began nevirapine, lamivudine, and stavudine. Overall, 79 (54%) women had CD4 counts <250 cells/μL, 7 (5%) had grade II hepatotoxicity, and 4 (3%) had severe (grade III or IV) hepatotoxicity. All 4 women with severe hepatotoxicity had baseline CD4 counts ≥250 cells/μL (P = 0.02). Rates of skin toxicity, anemia, and peripheral neuropathy did not differ by CD4 cell count group. Overall, 12 (8%) women changed or discontinued HAART as a result of drug toxicity. Conclusions:Severe hepatotoxicity from nevirapine-containing HAART in this cohort of pregnant women was more common at higher CD4 counts (6% vs. 0% among women with CD4 counts ≥250 cells/μL and CD4 counts <250 cells/μL, respectively), suggesting that laboratory monitoring is necessary when administering nevirapine-containing regimens to pregnant women with CD4 counts ≥250 cells/μL.

Preclinical Safety Assessments of UC781 Anti-Human Immunodeficiency Virus Topical Microbicide Formulations

ABSTRACT The nonnucleoside reverse transcriptase inhibitor UC781 is under development as a potential microbicide to prevent sexual transmission of human immunodeficiency virus type 1 (HIV-1). Two gel formulations of UC781 (0.1% and 1.0%) were evaluated in a range of preclinical safety assessments, including systemic absorption analysis following topical application in the pig-tailed macaque models for vaginally and rectally applied topical microbicides. High-sensitivity high-performance liquid chromatography analysis of serum samples showed that no systemic absorption of UC781 was detected after repeated vaginal or rectal application of either product. However, high levels of UC781 were detectable in the cervicovaginal lavage samples up to 6 h after product exposure. Both formulations were safe to the vaginal microenvironment, even with repeated daily use, as evidenced by colposcopy, cytokine analysis, and lack of impact on vaginal microflora. By contrast, rectal application of the 1.0% UC781 formulation caused an increased expression of numerous cytokines not observed after rectal application of the 0.1% UC781 formulation. These results provide additional support for the continued development of UC781 formulations as anti-HIV microbicides.

Bacterial vaginosis and the risk of trichomonas vaginalis acquisition among HIV-1-negative women.

Background The vaginal microbiota may play a role in mediating susceptibility to sexually transmitted infections, including Trichomonas vaginalis (TV). Methods Data were analyzed from HIV-1-seronegative women participating in HIV Prevention Trials Network Protocol 035. At quarterly visits for up to 30 months, participants completed structured interviews and specimens were collected for genital tract infection testing. T. vaginalis was detected by saline microscopy. Bacterial vaginosis (BV) was characterized by Gram stain using the Nugent score (BV = 7–10; intermediate = 4–6; normal = 0–3 [reference group]). Cox proportional hazards models stratified by study site were used to assess the association between Nugent score category at the prior quarterly visit and TV acquisition. Results In this secondary analysis, 2920 participants from Malawi, South Africa, United States, Zambia, and Zimbabwe contributed 16,259 follow-up visits. Bacterial vaginosis was detected at 5680 (35%) visits, and TV was detected at 400 (2.5%) visits. Adjusting for age, marital status, hormonal contraceptive use, unprotected sex in the last week and TV at baseline, intermediate Nugent score, and BV at the prior visit were associated with an increased risk of TV (intermediate score: adjusted hazard ratio [aHR], 1.73; 95% confidence interval [CI], 1.21–2.19; BV: aHR, 2.40; 95% CI, 1.92–3.00). Sensitivity analyses excluding 211 participants with TV at baseline were similar to those from the full study population (intermediate score: aHR, 1.54; 95% CI, 1.10–2.14; BV: aHR, 2.23; 95% CI, 1.75–2.84). Conclusions Women with a Nugent score higher than 3 were at an increased risk for acquiring TV. If this relationship is causal, interventions that improve the vaginal microbiota could contribute to reductions in TV incidence.

High uptake of postpartum hormonal contraception among HIV-1-seropositive women in Kenya.

Objectives: The objectives of this study were to determine patterns of contraceptive utilization among sexually active HIV-1-seropositive women postpartum and to identify correlates of hormonal contraception uptake. Goal: The goal of this study was to improve delivery of family planning services to HIV-1-infected women in resource-limited settings. Study Design: HIV-1-infected pregnant women were followed prospectively in a perinatal HIV-1 transmission study. Participants were referred to local clinics for contraceptive counseling and management. Results: Among 319 HIV-1-infected women, median time to sexual activity postpartum was 2 months and 231 (72%) women used hormonal contraception for at least 2 months during follow-up, initiating use at approximately 3 months postpartum (range, 1–11 months). Overall, 101 (44%) used DMPA, 71 (31%) oral contraception, and 59 (25%) switched methods during follow-up. Partner notification, infant mortality, and condom use were similar between those using and not using contraception. Conclusions: Using existing the healthcare infrastructure, it is possible to achieve high levels of postpartum hormonal contraceptive utilization among HIV-1-seropositive women.

Assessing the effect of hormonal contraception on HIV acquisition in observational data: challenges and recommended analytic approaches.

Introduction:Determining whether hormonal contraception, particularly the injectable contraceptive depot-medroxyprogesterone acetate (DMPA), increases a womans risk of HIV acquisition is a priority question for public health. However, assessing the relationship between various hormonal contraceptive methods and HIV acquisition with observational data involves substantial analytic design issues and challenges. Studies to date have used inconsistent approaches and generated a body of evidence that is complex and challenging to interpret. Methods:In January 2013, the United States Agency for International Development and FHI 360 supported a meeting of epidemiologists, statisticians, and content experts to develop recommendations for future observational analyses of hormonal contraception and HIV acquisition. Results:Meeting participants generated recommendations regarding careful definition of exposure groups; handling potential confounders, mediators, and effect modifiers; estimating and addressing the magnitude of measurement error; using multiple methods to account for pregnancy; and exploring the potential for differential exposure to HIV-infected partners. Advantages and disadvantages of various statistical approaches to account for time-varying confounding and estimating total and direct effects were also discussed. Conclusion:Implementing these recommendations in future observational hormonal contraception-HIV acquisition analyses will enhance interpretation of existing studies and strengthen the overall evidence base for this complex and important area.

Vaginal and Rectal Topical Microbicide Development: Safety and Efficacy of 1.0% Savvy (c31g) in the Pigtailed Macaque

Background: A 1.0% gel formulation of C31G, a surfactant, has been shown to have in vitro antiviral and antibacterial activity. Goal: The goal of this study was to evaluate the safety and efficacy of vaginal and rectal applications of 1.0% Savvy (C31G) in the nonhuman primate model. Study Design: The safety of repeated 1.0% C31G application was evaluated by microflora, pH, vaginal biopsy, colposcopy, and rectal lavage. Efficacy in preventing chlamydial infection was documented by culture, nucleic acid amplification tests, and serology. Results: Repeated applications of Savvy (1.0% C31G) were not associated with significant changes in pH, microflora, or inflammatory infiltrates on tissues. No significant differences in epithelial desquamation were noted after rectal product use compared with placebo. Four of 6 animals were protected from chlamydial infection after pretreatment with Savvy. C31G was shown to be safe to both vaginal and rectal mucosal tissues and to the microflora with repeated daily use. Conclusion: Savvy has an acceptable safety profile after repeated vaginal and rectal use. A single intravaginal application of 1.0% C31G provided partial protection from acquiring cervical chlamydial infection.

Risk of HIV-1 acquisition among women who use different types of injectable progestin contraception in South Africa: a prospective cohort study.

BACKGROUND Several observational studies have reported that HIV-1 acquisition seems to be higher in women who use depot medroxyprogesterone acetate (DMPA) than in those who do not use hormonal contraception. We aimed to assess whether two injectable progestin-only contraceptives, DMPA and norethisterone enanthate (NET-EN), confer different risks of HIV-1 acquisition. METHODS We included data from South African women who used injectable contraception while participating in theVOICE study, a multisite, randomised, placebo-controlled trial that investigated the safety and efficacy of three formulations of tenofovir for prevention of HIV-1 infection in women between Sept 9, 2009, and Aug 13, 2012. Women were assessed monthly for contraceptive use and incident infection. We estimated the difference in incident HIV-1infection between DMPA and NET-EN users by Cox proportional hazards regression analyses in this prospective cohort. The VOICE trial is registered with ClinicalTrials.gov, NCT00705679. FINDINGS 3141 South African women using injectable contraception were included in the present analysis: 1788 (56·9%)solely used DMPA, 1097 (34·9%) solely used NET-EN, and 256 (8·2%) used both injectable types at different times during follow-up. During 2733·7 person-years of follow-up, 207 incident HIV-1 infections occurred (incidence7·57 per 100 person-years, 95% CI 6·61–8·68). Risk of HIV-1 acquisition was higher among DMPA users (incidence 8·62 per 100 person-years, 95% CI 7·35–10·11) than among NET-EN users (5·67 per 100 person-years, 4·35–7·38;hazard ratio 1·53, 95% CI 1·12–2·08; p=0·007). This association persisted when adjusted for potential confoundingvariables (adjusted hazard ratio [aHR] 1·41, 95% CI 1·06–1·89; p=0·02). Among women seropositive for herpes simplex virus type 2 (HSV-2) at enrolment, the aHR was 2·02 (95% CI 1·26–3·24) compared with 1·09 (0·78–1·52)for HSV-2-seronegative women (pinteraction=0·07). INTERPRETATION Although moderate associations in observational analyses should be interpreted with caution, thesefi ndings suggest that NET-EN might be an alternative injectable drug with a lower HIV risk than DMPA in high HIV-1 incidence settings where NET-EN is available. FUNDING National Institutes of Health, Mary Meyer Scholars Fund, and the Ruth Freeman Memorial Fund.

P3.090 Bacterial Vaginosis and the Risk of Trichomonas Vaginalis Acquisition Among HIV-1 Negative Women

Background The vaginal microbiota may play a role in mediating susceptibility to sexually transmitted infections, including Trichomonas vaginalis (TV). This analysis evaluated the association between bacterial vaginosis (BV) and incident TV among women enrolled in a biomedical HIV prevention trial. Methods Data were analysed from HIV-1 seronegative women participating in HIV Prevention Trials Network Protocol 035. At quarterly visits for up to 30 months, participants completed structured interviews and specimens were collected for genital tract infection testing. TV was detected by saline microscopy. BV was characterised by Gram stain using the Nugent score (BV = 7–10; intermediate = 4–6; normal = 0–3 [reference group]). Cox proportional hazards models stratified by study site were used to assess the association between BV at the prior quarterly visit and TV acquisition. Participants were censored at their first TV infection or if they became pregnant or HIV-infected. Results This secondary analysis included 2,804 participants from Malawi, South Africa, USA, Zambia and Zimbabwe who contributed 13,977 follow-up visits. BV was detected at 5,184 (37.1%) visits and TV was detected at 352 (2.5%) visits. After adjusting for age, marital status, hormonal contraceptive use, sexual activity and TV at baseline, intermediate microbiota and BV at the prior visit were independently associated with an increased risk of TV (intermediate microbiota: adjusted hazard ratio [aHR] = 1.74, 95% confidence interval [CI] 1.22, 2.47; BV: aHR = 3.25, 95% CI 2.53–4.17). TV at baseline was also associated with an increased risk of TV (aHR = 2.54; 95% CI 1.91, 3.36). Sensitivity analyses excluding 202 women with baseline TV showed similar results (BV: aHR = 3.18; 95% CI 2.42 – 2.19). Conclusions Women with a Nugent score > 3 were at an increased risk of acquiring TV. If this relationship is causal, interventions that decrease the incidence of BV and promote a normal vaginal microbiota could potentially contribute to reductions in TV incidence.

Development of a nonhuman primate model for Trichomonas vaginalis infection.

Objective: Trichomoniasis, caused by Trichomonas vaginalis, is a prevalent sexually transmitted infection associated with increased risk of HIV infection. An animal model of T. vaginalis infection would enable scientists to further investigate trichomoniasis. Study Design: Seven macaques (4 test vs. 3 control) were enrolled in a 2-week pilot study. Eight additional animals participated in a 2-arm (T. vaginalis vs. sham inoculated) crossover study lasting 5 weeks before treatment. In all, 12 Macaca nemestrina monkeys were challenged with a single intravaginal inoculation of 6.6 to 7.1 × 105 trichomonads (ATCC 50148). Vaginal culture (InPouch TV), colposcopy, microbiology, pH, and cervical cytokines were assessed at baseline, day 2, and weekly thereafter. Results: Ten of 12 challenged animals tested positive for trichomoniasis for 2 weeks or longer. One animal tested positive on days 2 and 7 but negative thereafter. Only one animal was not infected. Oral metronidazole treatment (35 mg/kg per day for 3 days) resolved infection in all animals. Trichomoniasis infection did not lead to shifts in vaginal microbiology or pH. Conclusions: A single T. vaginalis inoculation results in persistent infection in the pigtailed macaque.