Lydia Soto-Torres

Safety and effectiveness of BufferGel and 0.5% PRO2000 gel for the prevention of HIV infection in women

Objective:To determine the safety and effectiveness of BufferGel and 0.5% PRO2000 microbicide gels for the prevention of male-to-female HIV transmission. Design:Phase II/IIb, randomized, placebo-controlled trial with three double-blinded gel arms and an open-label no gel arm. Methods:Study participants from Malawi, South Africa, Zambia, Zimbabwe, and the USA were instructed to apply study gel up to 1 h before each sex act and safety, sexual behavior, pregnancy, gel adherence, acceptability, and HIV serostatus were assessed during follow-up. Results:The 3101 enrolled women were followed for an average of 20.4 months with 93.6% retention and 81.1% self-reported gel adherence. Adverse event rates were similar in all study arms. HIV incidence rates in the 0.5% PRO2000 gel, BufferGel, placebo gel, and no gel arms were 2.70, 4.14, 3.91, and 4.02 per 100 women-years, respectively. HIV incidence in the 0.5% PRO2000 gel arm was lower than the placebo gel arm (hazard ratio = 0.7, P = 0.10) and the no gel arm (hazard ratio = 0.67, P = 0.06). HIV incidence rates were similar in the BufferGel and both placebo gel (hazard ratio = 1.10, P = 0.63) and no gel control arms (hazard ratio = 1.05, P = 0.78). HIV incidence was similar in the placebo gel and no gel arms (hazard ratio = 0.97, P = 0.89). Conclusion:The 0.5% PRO2000 gel demonstrated a modest 30% reduction in HIV acquisition in women. However, these results were not statistically significant and subsequent findings from the Microbicide Development Programme (MDP) 301 trial have confirmed that 0.5% PRO2000 gel has little or no protective effect. BufferGel did not alter the risk of HIV infection. Both products were well tolerated.

Safety and tolerability of tenofovir vaginal gel in abstinent and sexually active HIV-infected and uninfected women.

Objectives:To establish the highest practical dose and frequency (HPDF) of 0.3% or 1% tenofovir vaginal gel applied once or twice daily by sexually abstinent HIV-uninfected women, and to evaluate the safety, tolerability and systemic pharmacokinetics of the HPDF in abstinent and sexually active HIV-negative and HIV-infected women. Methods:Eighty-four women, enrolled in sequential cohorts, used the study product for 14 consecutive intermenstrual days. Safety laboratory assessments and pelvic examinations were carried out during five study visits, with colposcopy at enrollment and on day 14. Samples for pharmacokinetics were collected before and after the initial tenofovir gel use and at day 13. Results:The 1% tenofovir gel used twice daily was as well tolerated as other regimens used by the 48 HIV-negative sexually abstinent women, establishing the HPDF. Although 92% of the women reported at least one adverse event, the majority were mild (87%) and involved the genitourinary tract (70%). One possibly product-related severe adverse event involving lower abdominal cramping was reported by a sexually abstinent woman who used 0.3% gel twice daily. Serum tenofovir levels were low but detectable in 14 of the 25 women. No new HIV RNA resistance mutations were detected after 2 weeks of tenofovir gel in the 24 HIV-infected participants. No significant systemic toxicity was detected. Conclusion:A 2-week course of 1% tenofovir vaginal gel used twice daily was well tolerated in sexually abstinent and sexually active HIV-negative and HIV-positive women. Systemic tenofovir absorption occurred. Expanded safety and effectiveness testing is warranted.

MTN-001: Randomized Pharmacokinetic Cross-Over Study Comparing Tenofovir Vaginal Gel and Oral Tablets in Vaginal Tissue and Other Compartments

Background Oral and vaginal preparations of tenofovir as pre-exposure prophylaxis (PrEP) for human immunodeficiency virus (HIV) infection have demonstrated variable efficacy in men and women prompting assessment of variation in drug concentration as an explanation. Knowledge of tenofovir concentration and its active form, tenofovir diphosphate, at the putative vaginal and rectal site of action and its relationship to concentrations at multiple other anatomic locations may provide key information for both interpreting PrEP study outcomes and planning future PrEP drug development. Objective MTN-001 was designed to directly compare oral to vaginal steady-state tenofovir pharmacokinetics in blood, vaginal tissue, and vaginal and rectal fluid in a paired cross-over design. Methods and Findings We enrolled 144 HIV-uninfected women at 4 US and 3 African clinical research sites in an open label, 3-period crossover study of three different daily tenofovir regimens, each for 6 weeks (oral 300 mg tenofovir disoproxil fumarate, vaginal 1% tenofovir gel [40 mg], or both). Serum concentrations after vaginal dosing were 56-fold lower than after oral dosing (p<0.001). Vaginal tissue tenofovir diphosphate was quantifiable in ≥90% of women with vaginal dosing and only 19% of women with oral dosing. Vaginal tissue tenofovir diphosphate was ≥130-fold higher with vaginal compared to oral dosing (p<0.001). Rectal fluid tenofovir concentrations in vaginal dosing periods were higher than concentrations measured in the oral only dosing period (p<0.03). Conclusions Compared to oral dosing, vaginal dosing achieved much lower serum concentrations and much higher vaginal tissue concentrations. Even allowing for 100-fold concentration differences due to poor adherence or less frequent prescribed dosing, vaginal dosing of tenofovir should provide higher active site concentrations and theoretically greater PrEP efficacy than oral dosing; randomized topical dosing PrEP trials to the contrary indicates that factors beyond tenofovir’s antiviral effect substantially influence PrEP efficacy. Trial Registration ClinicalTrials.gov NCT00592124

Women's Experiences with Oral and Vaginal Pre-Exposure Prophylaxis: The VOICE-C Qualitative Study in Johannesburg, South Africa

Background In VOICE, a multisite HIV pre-exposure prophylaxis (PrEP) trial, plasma drug levels pointed to widespread product nonuse, despite high adherence estimated by self-reports and clinic product counts. Using a socio-ecological framework (SEF), we explored socio-cultural and contextual factors that influenced participants’ experience of daily vaginal gel and oral tablet regimens in VOICE. Methods In Johannesburg, a qualitative ancillary study was concurrently conducted among randomly selected VOICE participants assigned to in-depth interviews (n = 41), serial ethnographic interviews (n = 21), or focus group discussions (n = 40). Audiotaped interviews were transcribed, translated, and coded thematically for analysis. Results Of the 102 participants, the mean age was 27 years, and 96% had a primary sex partner with whom 43% cohabitated. Few women reported lasting nonuse, which they typically attributed to missed visits, lack of product replenishments, and family-related travel or work. Women acknowledged occasionally skipping or mistiming doses because they forgot, were busy, felt lazy or bored, feared or experienced side effects. However, nearly all knew or heard of other study participants who did not use products daily. Three overarching themes emerged from further analyses: ambivalence toward research, preserving a healthy status, and managing social relationships. These themes highlighted the profound and complex meanings associated with participating in a blinded HIV PrEP trial and taking antiretroviral-based products. The unknown efficacy of products, their connection with HIV infection, challenges with daily regimen given social risks, lack of support–from partners and significant others–and the relationship tradeoffs entailed by using the products appear to discourage adequate product use. Conclusions Personal acknowledgment of product nonuse was challenging. This qualitative inquiry highlighted key influences at all SEF levels that shaped women’s perceptions of trial participation and experiences with investigational products. Whether these impacted women’s behaviors and may have contributed to ineffective trial results warrants further investigation.

Safety and acceptability of cellulose sulfate as a vaginal microbicide in HIV-infected women.

Objectives:Few studies of topical microbicides have assessed their safety in HIV-infected women. We conducted this study to evaluate the safety and acceptability of 6% cellulose sulfate (CS) gel as a vaginal microbicide in sexually abstinent and active HIV-infected women. Methods:Fifty-nine HIV-infected women were enrolled in a randomized double-blind placebo-controlled study comparing 6% CS to placebo gel used for 14 days. Sexually abstinent women applied gel once or twice daily and sexually active women used gel once daily. Results:CS gel was safe with no reported severe or life-threatening adverse events (AE). Thirty-nine (66%) of the participants experienced urogenital AE judged as probably or possibly related to gel. The majority (51%) of these participants reported only mild events. Fewer women (62%) who used CS experienced urogenital AE than those assigned to placebo gel (70%) (P = 0.59). Eleven (19%) women experienced intermenstrual bleeding judged to be probably or possibly related to gel use (four in the CS and seven in the placebo gel group). There was no increase in AE by frequency of gel use or sexual activity with the exception of abdominal/pelvic pain which was noted more frequently with twice daily use among sexually abstinent women. Women and men found the gel highly acceptable. Conclusions:This Phase I study demonstrated that CS vaginal gel was safe, well tolerated and acceptable by HIV-infected women and their male partners. Thus, further development of CS is warranted as a potential method to prevent HIV transmission and acquisition.

A randomized trial to assess anti-HIV activity in female genital tract secretions and soluble mucosal immunity following application of 1% tenofovir gel.

Background Preclinical and early phase clinical microbicide studies have not consistently predicted the outcome of efficacy trials. To address this gap, candidate biomarkers of microbicide pharmacodynamics and safety were evaluated in a double-blind, placebo-controlled trial of tenofovir gel, the first microbicide to demonstrate significant protection against HIV acquisition. Methods 30 women were randomized to apply a single daily dose of tenofovir or placebo gel for 14 consecutive days. Anti-HIV activity was measured in cervicovaginal lavage (CVL) on Days 0, 3, 7, 14 and 21 by luciferase assay as a surrogate marker of pharmacodynamics. Endogenous activity against E. coli and HSV-2 and concentrations of immune mediators were quantified in CVL as candidate biomarkers of safety. Tenofovir levels were measured in CVL and blood. Results A significant increase in anti-HIV activity was detected in CVL from women who applied tenofovir gel compared to their endogenous anti-HIV activity in genital tract secretions on Day 0 and compared to activity in CVL from women in the placebo group. The activity correlated significantly with CVL concentration of tenofovir (r = 0.6, p<0.001) and fit a sigmoid Emax pharmacodynamic model. Anti-HIV activity in CVL from women who applied tenofovir persisted when virus was introduced in semen, whereas endogenous anti-HIV activity decreased. Tenofovir did not trigger an inflammatory response or induce sustained loss in endogenous antimicrobial activity or immune mediators. Conclusions Tenofovir gel had no deleterious impact on soluble mucosal immunity. The increased anti-HIV activity in CVL, which persisted in the presence of semen and correlated with tenofovir concentration, is consistent with the efficacy observed in a recent clinical trial. These results promote quantified CVL anti-HIV activity as a surrogate of tissue pharmacodynamics and as a potential biomarker of adherence to product. This simple, feasible and inexpensive bioassay may promote the development of models more predictive of microbicide efficacy. Trial Registration ClinicalTrials.gov NCT00594373

Challenges of a hidden epidemic: HIV prevention among women in the United States.

HIV/AIDS trends in the United States depict a concentrated epidemic with hot spots that vary by location, poverty, race/ethnicity, and transmission mode. HIV/AIDS is a leading cause of death among US women of color; two-thirds of new infections among women occur in black women, despite the fact that black women account for just 14% of the US female population. The gravity of the HIV epidemic among US women is often not appreciated by those at risk and by the broader scientific community. We summarize the current epidemiology of HIV/AIDS among US women and discuss clinical, research, and public health intervention components that must be brought together in a cohesive plan to reduce new HIV infections in US women. Only by accelerating research and programmatic efforts will the hidden epidemic of HIV among US women emerge into the light and come under control.

Phase 1 Safety, Pharmacokinetics, and Pharmacodynamics of Dapivirine and Maraviroc Vaginal Rings: a Double-Blind Randomized Trial

Background:Variable adherence limits effectiveness of daily oral and intravaginal tenofovir-containing pre-exposure prophylaxis. Monthly vaginal antiretroviral rings are one approach to improve adherence and drug delivery. Methods:MTN-013/IPM 026, a multisite, double-blind, randomized, placebo-controlled trial in 48 HIV-negative US women, evaluated vaginal rings containing dapivirine (DPV) (25 mg) and maraviroc (MVC) (100 mg), DPV only, MVC only, and placebo used continuously for 28 days. Safety was assessed by adverse events. Drug concentrations were quantified in plasma, cervicovaginal fluid (CVF), and cervical tissue. Cervical biopsy explants were challenged with HIV ex vivo to evaluate pharmacodynamics. Results:There was no difference in related genitourinary adverse events between treatment arms compared with placebo. DPV and MVC concentrations rose higher initially before falling more rapidly with the combination ring compared with relatively stable concentrations with the single-drug rings. DPV concentrations in CVF were 1 and 5 log10 greater than cervical tissue and plasma for both rings. MVC was consistently detected only in CVF. DPV and MVC CVF and DPV tissue concentrations dropped rapidly after ring removal. Cervical tissue showed a significant inverse linear relationship between HIV replication and DPV levels. Conclusions:In this first study of a combination microbicide vaginal ring, all 4 rings were safe and well tolerated. Tissue DPV concentrations were 1000 times greater than plasma concentrations and single drug rings had more stable pharmacokinetics. DPV, but not MVC, demonstrated concentration-dependent inhibition of HIV-1 infection in cervical tissue. Because MVC concentrations were consistently detectable only in CVF and not in plasma, improved drug release of MVC rings is needed.

Postcoital Bioavailability and Antiviral Activity of 0.5% PRO 2000 Gel: Implications for Future Microbicide Clinical Trials

Background The pharmacokinetics and pharmacodynamics of vaginal microbicides are typically assessed among sexually abstinent women. However, the physical act of sex may modulate gel distribution, and preclinical studies demonstrate seminal plasma interferes with the antiviral activity of several microbicides. This study compared the biological activity and concentration of PRO 2000 in cervicovaginal lavage (CVL) collected in the absence or following coitus. Methods CVL samples were collected from ten heterosexual couples at baseline, after sex, after a single dose of 0.5% PRO 2000 gel and sex, and after gel application without sex. The impact of CVL on HIV-1 infection of TZM-bl cells and HSV-2 infection of CaSki cells was monitored by luciferase and plaque assay, respectively. PRO 2000 concentrations were measured by fluorescence. Results CVL collected after PRO 2000 application significantly inhibited HIV-1 and HSV-2 (p = 0.01). However, the antiviral activity was reduced following sex and no significant protective effect was observed in postcoital CVL obtained in the presence compared to the absence of PRO 2000 for HIV (p = 0.45) or HSV-2 (p = 0.56). Less PRO 2000 was recovered in postcoital CVL, which, in conjunction with interference by seminal plasma, may have contributed to lower antiviral activity. Conclusions Postcoital responses to PRO 2000 differ from precoital measures and the results obtained may provide insights into the clinical trial findings in which there was no significant protection against HIV-1 or HSV-2. Postcoital studies should be incorporated into clinical studies before embarking on large-scale efficacy trials.

HIV Acquisition Among Women From Selected Areas of the United States: A Cohort Study

BACKGROUND Women account for 23% of newly diagnosed HIV infections in the United States, but there are few recent, well-characterized cohorts of U.S. women in whom behavior characteristics and HIV acquisition have been well-described. OBJECTIVE To evaluate HIV incidence and describe behaviors among U.S. women residing in areas of high HIV prevalence. DESIGN Multisite, longitudinal cohort of women who had HIV rapid testing and audio computer-assisted self-interviews at baseline and every 6 months for up to 12 months. (ClinicalTrials.gov: NCT00995176) SETTING 10 urban and periurban communities with high HIV prevalence and poverty rates, located in the northeastern and southeastern United States. PATIENTS Venue-based sampling was used to recruit women aged 18 to 44 years who recently had unprotected sex and had 1 or more additional personal or partner risk factors and no self-reported previous HIV diagnosis. MEASUREMENTS HIV prevalence and incidence, frequency of HIV risk behaviors, and health status perceptions. RESULTS Among 2099 high-risk women (85.9% black and 11.7% of Hispanic ethnicity), 32 (1.5%) were diagnosed with HIV infection at enrollment. Annual HIV incidence was 0.32% (95% CI, 0.14% to 0.74%). Older age, substance use, and knowing a partner had HIV were associated with HIV prevalence. Ten women died during the study (0.61% per year). LIMITATIONS Longitudinal assessment of risk behaviors was limited to a maximum of 12 months. There were few incident HIV infections, precluding identification of characteristics predictive of HIV acquisition. CONCLUSION This study enrolled a cohort of women with HIV incidence substantially higher than the Centers for Disease Control and Prevention national estimate in the general population of U.S. black women. Concerted efforts to improve preventive health care strategies for HIV and overall health status are needed for similar populations. PRIMARY FUNDING SOURCE National Institutes of Health.