Methodological Lessons from Clinical Trials and the Future of Microbicide Research

High adherence to intermittent and continuous use of a contraceptive vaginal ring among women in a randomized controlled trial in Kigali, Rwanda

Background

The introduction of female-initiated drug-delivery methods, including vaginal rings, have proven to be a promising avenue to address sexually transmitted infections and unintended pregnancies, which disproportionally affects women and girls in sub-Saharan Africa. Efficient uptake of existing and new technologies such as vaginal rings requires in depth understanding of product adherence. This remains a major challenge as data on adherence to vaginal rings from African countries is limited. In this study, we explored adherence of contraceptive vaginal ring (NuvaRing®) use in Kigali, Rwanda using a mixed methods approach.

Methods

We collected quantitative and qualitative data at multiple time points from women participating in a clinical trial exploring the safety and acceptability of either intermittent or continuous use of the NuvaRing®. Various adherence categories were used including monthly and cumulative adherence measurement. The quantitative data were analysed using R and the qualitative data were analysed using a deductive, content-analytical approach based on categories related to the quantitative adherence measures. All data were compared and triangulated.

Results

Data from 120 enrolled participants showed that self-reported adherence was high at every study visit in both study groups. At first study visit 80% of the intermittent ring users and 79.7% of the continuous ring users reported perfect adherence (assessed as "the ring was never out"). Reporting of ring expulsions and removals were highest (28.3%) at the beginning of the trial. Self-reported perfect ring adherence increased during the study and reports of ring expulsions and removals declined as familiarity with this contraceptive method increased. The percentage of women with perfect cumulative adherence was non-significantly higher in the intermittent (61.7%) than in the continuous use group (54.3%). The low rate of discrepant adherence data after triangulation (6%) is in line with the perception of the participants as adherent throughout the study.

Conclusions

Self-reported adherence in both study groups was high with removals and expulsions being within the expected product range. Comprehensive adherence data triangulation allowed for a deeper understanding of context-driven behaviour that shaped adherence patterns and challenges. Our data categorisation and triangulation approach has shown potential for implementation in future vaginal ring studies aiming to better understand and measure adherence.

Adherence, safety, and choice of the monthly dapivirine vaginal ring or oral emtricitabine plus tenofovir disoproxil fumarate for HIV pre-exposure prophylaxis among African adolescent girls and young women: a randomised, open-label, crossover trial

BACKGROUND

Half of new HIV acquisitions in Africa occur in adolescent girls and young women. Pre-exposure prophylaxis (PrEP) with oral tenofovir disoproxil fumarate plus emtricitabine or the monthly dapivirine vaginal ring is efficacious but has lower adherence and effectiveness among adolescent girls and young women. We aimed to assess product adherence, safety, and choice of oral PrEP compared with the dapivirine ring among African adolescent girls and young women.

METHODS

MTN-034/REACH was a randomised, open-label, phase 2a crossover trial among HIV-seronegative, non-pregnant adolescent girls and young women aged 16-21 years at four clinical research sites in South Africa, Uganda, and Zimbabwe. Participants were randomly assigned (1:1) to either the dapivirine ring or daily oral PrEP (200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate) for 6 months, then switched to the other product option for 6 months, followed by a third 6-month period in which participants were given a choice of oral PrEP, the dapivirine ring, or neither. Fixed block randomisation was used, stratified by site. The primary adherence endpoint was use of each product during the randomised periods, with high use defined as tenofovir-diphosphate concentrations greater than or equal to 700 fmol/punch (associated with taking an average of four or more tablets per week in the previous month) and greater than or equal to 4 mg dapivirine released from the returned ring (continuous use for 28 days in the previous month) based on residual drug concentrations. The primary safety endpoint was grade 2 or higher adverse events during each randomised period of 24 weeks of ring and oral PrEP. This trial is registered at ClinicalTrials.gov, NCT03593655.

FINDINGS

From Feb 6, 2019 to Sept 9, 2021, 396 adolescent girls and young women were screened, 247 of whom were enrolled and randomly assigned (6 months of the ring followed by 6 months of oral PrEP n=124; 6 months of oral PrEP followed by 6 months of the ring n=123). Median age was 18 years (IQR 17-19). 54 grade 2 or higher product-related adverse events were reported during oral PrEP and five during dapivirine ring use, with no product-related serious adverse events. High adherence was observed in 753 (57%) of the 1316 oral PrEP visits and 806 (57%) of the 1407 dapivirine ring visits. Four women acquired HIV during follow-up.

INTERPRETATION

Adherence was moderately high and similar between oral PrEP and the dapivirine ring with favourable safety and tolerability. Oral PrEP and the dapivirine ring are effective, safe, and well tolerated HIV prevention options for adolescent girls and young women who would benefit from a choice of PrEP formulations to meet their needs and preferences.

FUNDING

National Institutes of Health.

Adherence to methotrexate and associated factors considering social desirability in patients with rheumatoid arthritis: a multicenter cross-sectional study

BACKGROUND

Assessing medication adherence in rheumatoid arthritis (RA) is clinically significant as low adherence is associated with high disease activity. Self-reported medication adherence surveys have been shown to have problems with overestimation of adherence due to social desirability bias. However, no MTX adherence studies adjusted for social desirability have been conducted to date. This study aimed to evaluate adherence to MTX and perform an investigatory search for factors associated with MTX adherence including social desirability.

METHODS

This cross-sectional multicenter study was conducted among adult RA patients consuming oral MTX for ≥ 3 months. We examined the distribution of MTX adherence, according to the eight-item Morisky Medication Adherence Scale (MMAS-8). Social desirability was using the Social Desirability Scale (SDS). Furthermore, an exploratory factor analysis involving social desirability was examined to identify factors associated with MTX adherence using linear regression analysis. To deal with missing values, we used multiple imputations with chained equations methods.

RESULTS

A total of 165 RA patients were enrolled. The median age was 64 years, and 86.1% were women. Based on the MMAS-8, low, medium, and high adherences were noted in 12.1%, 60.0%, and 27.9% of participants, respectively. High social desirability (coefficient, 0.14; 95% confidence interval [CI], 0.05-0.23; p < 0.05) and high age (coefficient per 10 years, 0.16; 95% CI, 0.01-0.03; p < 0.05) were associated with high MTX adherence, whereas full-time work was negatively associated with high MTX adherence (coefficient, -0.50; 95% CI, -0.95--0.05; p < 0.05).

CONCLUSIONS

A large proportion of patients with RA do not take MTX as prescribed. High social desirability, high educational level, and non-full-time work may be associated with high MTX adherence. Physicians should confirm MTX adherence before switching or adding disease-modifying anti-rheumatic drugs in cases of uncontrolled disease activity.

Acceptability of PC-1005 Gel Administered Rectally to HIV-1 Seronegative Adults at Three Different Volume Levels (MTN-037)

Multipurpose prevention technologies (MPT) have been increasingly researched for their dual-purpose preventative properties against HIV and other STIs. The acceptability of PC-1005, a topical MPT candidate, was explored among men and women participating in the MTN-037 Phase I trial at two U.S. sites (Pittsburgh, PA, and Birmingham, AL). We triangulated quantitative and qualitative assessments of the acceptability of three volumes (4 mL, 16 mL, 32 mL) of PC-1005 administered rectally (N = 12; 6 males, 6 females). Participants rated overall gel acceptability on a scale of 1-10, with a median of 7.17 (SD = 2.04) and had positive feelings about all three dose volumes, citing them to be very comfortable or comfortable (dose 1 = 91.7%; dose 2 = 91.7%; dose 3 = 83.3%). High acceptability of and comfort with all three dose volumes shows promise for PC-1005 as an MPT to prevent HIV and STIs, warranting future clinical development.

PrEP use and HIV seroconversion rates in adolescent girls and young women from Kenya and South Africa: the POWER demonstration project

INTRODUCTION

HIV incidence remains high among African adolescent girls and young women (AGYW). The primary objective of this study is to assess pre-exposure prophylaxis (PrEP) initiation, use, persistence and HIV acquisition among African AGYW offered PrEP in order to inform PrEP scale-up.

METHODS

POWER was a prospective implementation science evaluation of PrEP delivery for sexually active HIV-negative AGYW ages 16-25 in family planning clinics in Kisumu, Kenya and youth and primary healthcare clinics in Cape Town and Johannesburg, South Africa. Follow-up visits occurred at month 1 and quarterly for up to 36 months. PrEP users were defined based on the month 1 refill. PrEP persistence through month 6 was assessed using Kaplan-Meier survival analysis among AGYW with a month 1 visit, defining non-persistence as an ≥15 day gap in PrEP availability for daily dosing. PrEP execution was evaluated in a subset with PrEP supply from the prior visit sufficient for daily dosing by measuring blood tenofovir diphosphate (TFV-DP) levels.

RESULTS

From June 2017 to September 2020, 2550 AGYW were enrolled (1000 in Kisumu, 787 in Cape Town and 763 in Johannesburg). Median age was 21 years, 66% had a sexual partner of unknown HIV status, and 29% had chlamydia and 10% gonorrhoea. Overall, 2397 (94%) initiated PrEP and 749 (31%) had a refill at 1 month. Of AGYW who could reach 6 months of post-PrEP initiation follow-up, 128/646 (20%) persisted with PrEP for 6 months and an additional 92/646 (14%) had a gap and restarted PrEP. TFV-DP levels indicated that 47% (91/193) took an average of ≥4 doses/week. Sixteen HIV seroconversions were observed (incidence 2.2 per 100 person-years, 95% CI 1.2, 3.5); 13 (81%) seroconverters either did not have PrEP dispensed in the study interval prior to seroconversion or TFV-DP levels indicated <4 doses/week in the prior 6 weeks.

CONCLUSIONS

In this study of PrEP integration with primary care and reproductive health services for African AGYW, demand for PrEP was high. Although PrEP use decreased in the first months, an important fraction used PrEP through 6 months.  Strategies are needed to simplify PrEP delivery, support adherence and offer long-acting PrEP options to improve persistence and HIV protection.

Sharing Objective Measures of Adherence to a Vaginal Microbicide Promotes Candor About Actual Use and Bolsters Motivation to Prevent HIV

Discrepancies between self-reported and actual adherence to biomedical HIV interventions is common and in clinical trials can compromise the integrity of findings. One solution is to monitor adherence biomarkers, but it is not well understood how to navigate biomarker feedback with participants. We surveyed 42 counselors and interviewed a subset of 22 to characterize their perspectives about communicating with participants about residual drug levels, an objective marker of adherence, within MTN-025/HOPE, a Phase 3b clinical trial of a vaginal ring to prevent HIV. When biomarkers indicated low drug levels that mismatched high adherence by self-report, counselors encountered barriers to acceptance and comprehension among participants. However, discrepancies between low self-report and higher drug levels generally stimulated candor. Women recollected times they had not used the product and disclosed problems that counselors thought might otherwise have remained forgotten or concealed. Navigating conversations toward HIV prevention was easier at mid-range drug levels and when women indicated motivation to prevent HIV. Ratings of residual drug level offered a somewhat objective measure of adherence and protection that counselors perceived as meaningful to participants and as a valuable catalyst for broaching conversation about HIV prevention. However, communication about drug levels required that counselors navigate emotional barriers, respond skillfully to questions about accuracy, and pivot conversations non-judgmentally away from numerical results and toward the priority of HIV prevention. Findings suggest a role for biomarker feedback in future clinical trials as well as other clinical contexts where biomarkers may be monitored, to motivate disclosure of actual adherence and movement toward HIV prevention.Clinical Trial Number NCT02858037.

Vaginal Ring Use in a Phase 3 Microbicide Trial: A Comparison of Objective Measures and Self-reports of Non-adherence in ASPIRE

This analysis compares self-reports of product use with objective measures of non-adherence-quarterly plasma dapivirine levels and monthly residual dapivirine (DPV) levels in used rings-in MTN-020/ASPIRE, a phase 3 trial of a monthly DPV vaginal ring among women aged 18-45 years in Malawi, South Africa, Uganda and Zimbabwe. For participants on active product (N = 1211) we assessed self-reported monthly non-adherence, as measured by (1) whether the ring was ever out, and out for ≥ 12 h in the previous month and, (2) by a self-rating scale assessing ability to keep the vaginal ring inserted, and compared the self-reports to two biomarkers of non-use separately and as a composite measure. For this analysis, a plasma DPV value ≤ 95 pg/ml and residual ring ≥ 23.5 mg were used to classify non-adherence (i.e. the ring never being in the vagina the previous month). Compared to self-reports, non-adherence was found to be substantially higher for the composite measure as well as its two components, an indication that ring removal was likely underreported in the trial. The discrepancy between the self-report measure of ring outage and the composite indicator was greater for those aged 18-21 than for those older, evidence that younger women are more likely to underreport non-adherence. Despite underreporting of non-adherence, self-reports of the ring never being out were significant in predicting the composite objective measure. Furthermore, the association between the self-rating scale and the objective measure was in the expected direction and significant, although 11% of those 18-21 and 7% of those 22+ who rated their ability to keep the ring inserted as good, very good or excellent in the 4 weeks prior to exit were considered non-adherent according to the objective measure. This analysis indicates that while self-reports are significantly associated with objective measures of adherence in the ASPIRE trial, they were inflated-more so by those younger-and therefore may have limited utility identifying those who have challenges using products as directed. ClinicalTrials.gov number NCT01617096.

Long acting systemic HIV pre-exposure prophylaxis: an examination of the field

Oral pre-exposure prophylaxis for the prevention of HIV-1 transmission (HIV PrEP) has been widely successful as demonstrated by a number of clinical trials. However, studies have also demonstrated the need for patients to tightly adhere to oral dosing regimens in order to maintain protective plasma and tissue concentrations. This is especially true for women, who experience less forgiveness from dose skipping than men in clinical trials of HIV PrEP. There is increasing interest in long-acting (LA), user-independent forms of HIV PrEP that could overcome this adherence challenge. These technologies have taken multiple forms including LA injectables and implantables. Phase III efficacy trials are ongoing for a LA injectable candidate for HIV PrEP. This review will focus on the design considerations for both LA injectable and implantable platforms for HIV PrEP. Additionally, we have summarized the existing LA technologies currently in clinical and pre-clinical studies for HIV PrEP as well as other technologies that have been applied to HIV PrEP and contraceptives. Our discussion will focus on the potential application of these technologies in low resource areas, and their use in global women's health.

Evaluation of a Multidrug Assay for Monitoring Adherence to a Regimen for HIV Preexposure Prophylaxis in a Clinical Study, HIV Prevention Trials Network 073

Daily oral tenofovir disoproxil fumarate (TDF)-emtricitabine (FTC) is a safe and effective intervention for HIV preexposure prophylaxis (PrEP). We evaluated the performance of a qualitative assay that detects 20 antiretroviral (ARV) drugs (multidrug assay) in assessing recent PrEP exposure (detection limit, 2 to 20 ng/ml). Samples were obtained from 216 Black men who have sex with men (208 HIV-uninfected men and 8 seroconverters) who were enrolled in a study in the United States evaluating the acceptability of TDF-FTC PrEP (165 of the uninfected men and 5 of the seroconverters accepted PrEP). Samples from 163 of the 165 HIV-uninfected men who accepted PrEP and samples from all 8 seroconverters were also tested for tenofovir (TFV) and FTC using a quantitative assay (detection limit for both drugs, 0.31 ng/ml). HIV drug resistance was assessed in seroconverter samples. The multidrug assay detected TFV and/or FTC in 3 (1.4%) of the 208 uninfected men at enrollment, 84 (40.4%) of the 208 uninfected men at the last study visit, and 1 (12.5%) of the 8 seroconverters. No other ARV drugs were detected. The quantitative assay confirmed all positive results from the multidrug assay and detected TFV and/or FTC in 9 additional samples (TFV range, 0.65 to 16.5 ng/ml; FTC range, 0.33 to 14.6 ng/ml). Resistance mutations were detected in 4 of the 8 seroconverter samples. The multidrug assay had 100% sensitivity and specificity for detecting TFV and FTC at drug concentrations consistent with daily PrEP use. The quantitative assay detected TFV and FTC at lower levels, which also might have provided protection against HIV infection.

Misreporting of Product Adherence in the MTN-003/VOICE Trial for HIV Prevention in Africa: Participants' Explanations for Dishonesty

Consistent over-reporting of product use limits researchers' ability to accurately measure adherence and estimate product efficacy in HIV prevention trials. While lying is a universal characteristic of the human condition, growing evidence of a stark discrepancy between self-reported product use and biologic or pharmacokinetic evidence demands examination of the reasons research participants frequently misrepresent product use in order to mitigate this challenge in future research. This study (VOICE-D) was an ancillary post-trial study of the vaginal and oral interventions to control the epidemic (VOICE) phase IIb trial (MTN 003). It was conducted in three African countries to elicit candid accounts from former VOICE trial participants about why actual product use was lower than reported. In total 171 participants were enrolled between December 2012 and March 2014 in South Africa (n = 47), Uganda (n = 59) and Zimbabwe (n = 65). Data suggested that participants understood the importance of daily product use and honest reporting, yet acknowledged that research participants typically lie. Participants cited multiple reasons for misreporting adherence, including human nature, self-presentation with study staff, fear of repercussions (study termination resulting in loss of benefits and experience of HIV-related stigma), a permissive environment in which it was easy to get away with misreporting, and avoiding inconvenient additional counseling. Some participants also reported mistrust of the staff and reciprocal dishonesty about the study products. Many suggested real-time blood-monitoring during trials would encourage greater fidelity to product use and honesty in reporting. Participants at all sites understood the importance of daily product use and honesty, while also acknowledging widespread misreporting of product use. Narratives of dishonesty may suggest a wider social context of hiding products from partners and distrust about research, influenced by rumors circulating in clinic waiting-rooms and surrounding communities. Prevailing power hierarchies between staff and participants may exacerbate misreporting. Participants recognized and suggested that objective, real-time feedback is needed to encourage honest reporting.

Measurement of Vaginal Microbicide Adherence Using Visual Inspection as Compared to Ultra Violet Light Assessment of Returned Empty Gel Applicators

Accurate and objective measurement of adherence is critical in microbicide trials. We compared two applicator tests: visual inspection of returned empty tenofovir gel applicators (VIREA) and ultraviolet light (UVL) assessment in terms of sensitivity and specificity, and for concordance. Sensitivity and specificity analysis of 24 control applicators (12 known-inserted and 12 sham-inserted) at 4-months after receipt was 75.0 and 66.7 % for VIREA and 83.3 and 91.7 % for UVL, respectively. After an additional 3 months of storage sensitivity and specificity was 100 and 58.3 % for VIREA and 100 and 66.7 % for UVL, respectively. In January 2015, 1316 empty applicators were returned as used by 115 participants enrolled at one site in a randomized controlled trial. Assessment outcomes showed 78.8 % agreement between the techniques. Methods concurred that 22.0 % of the returned empty applicators appeared unused. By UVL assessment, 40.0 % of returned empty applicators had no evidence of vaginal insertion, translating to a potential 28.0 % less product used as compared to that returned as used by women. UVL assessment may be considered a more accurate and less subjective measure of adherence as compared to VIREA.

Reporting of Adherence in the VOICE Trial: Did Disclosure of Product Nonuse Increase at the Termination Visit?

VOICE-a phase 2B, placebo-controlled, randomized trial testing daily use of an antiretroviral tablet (tenofovir or Truvada) or daily use of tenofovir gel in 5029 women from South Africa, Uganda, and Zimbabwe-found none of the drug regimens effective in reducing HIV-1 acquisition in the intent-to-treat analysis. More than half of women assigned to active products in a case cohort sample had no drug detected in any plasma specimens tested during the trial. Yet, in response to questions asked of participants during the trial, ≥90 % of doses were reportedly taken. To explore factors associated with low adherence, a behavioral termination visit questionnaire was developed after early closure of the oral tenofovir and vaginal gel arms. We hypothesized that participants would be more forthcoming about nonuse after they exited the trial than during monthly/quarterly follow-up visits. Comparison of adherence reporting at routine follow-up visits with reporting at trial termination, however, indicates that disclosure of product nonadherence did not increase at the termination visit as anticipated. In resource-limited settings where women value the ancillary benefits provided by trial participation and are concerned that disclosure of nonuse may jeopardize trial participation, objective measures of adherence may yield more meaningful data regarding the inability or reluctance to use than measures of product use derived from self-report.

Pre-exposure Prophylaxis Adherence Measured by Plasma Drug Level in MTN-001: Comparison Between Vaginal Gel and Oral Tablets in Two Geographic Regions

Despite strong evidence that daily oral pre-exposure prophylaxis (PrEP) reduces HIV risk, effectiveness across studies has varied. Inconsistent adherence constitutes one explanation. Efforts to examine adherence are limited when they rely on self-reported measures. We examined recent adherence as measured by plasma tenofovir (TFV) concentration in participants of MTN-001, a phase 2 cross-over trial comparing oral tablet and vaginal gel formulations of TFV among 144 HIV-uninfected women at sites in the United States (U.S.) and sub-Saharan Africa (SSA). Adherence to daily product use was higher in the U.S. than in the SSA sites. Within region, however, adherence was similar between products. In the U.S., gel adherence was higher among married women, and lower among women using male condoms and injectable contraceptives. At the SSA sites, gel adherence was lower for younger women. Inconsistent adherence points to challenges in use of daily PrEP, even during a trial of short duration.

Biomarkers and biometric measures of adherence to use of ARV-based vaginal rings

Introduction

Poor adherence to product use has been observed in recent trials of antiretroviral (ARV)-based oral and vaginal gel HIV prevention products, resulting in an inability to determine product efficacy. The delivery of microbicides through vaginal rings is widely perceived as a way to achieve better adherence but vaginal rings do not eliminate the adherence challenges exhibited in clinical trials. Improved objective measures of adherence are needed as new ARV-based vaginal ring products enter the clinical trial stage.

Methods

To identify technologies that have potential future application for vaginal ring adherence measurement, a comprehensive literature search was conducted that covered a number of biomedical and public health databases, including PubMed, Embase, POPLINE and the Web of Science. Published patents and patent applications were also searched. Technical experts were also consulted to gather more information and help evaluate identified technologies. Approaches were evaluated as to feasibility of development and clinical trial implementation, cost and technical strength.

Results

Numerous approaches were identified through our landscape analysis and classified as either point measures or cumulative measures of vaginal ring adherence. Point measurements are those that give a measure of adherence at a particular point in time. Cumulative measures attempt to measure ring adherence over a period of time.

Discussion

Approaches that require modifications to an existing ring product are at a significant disadvantage, as this will likely introduce additional regulatory barriers to the development process and increase manufacturing costs. From the point of view of clinical trial implementation, desirable attributes would be high acceptance by trial participants, and little or no additional time or training requirements on the part of participants or clinic staff. We have identified four promising approaches as being high priority for further development based on the following measurements: intracellular drug levels, drug levels in hair, the accumulation of a vaginal analyte that diffuses into the ring, and the depletion of an intrinsic ring constituent.

Conclusions

While some approaches show significant promise over others, it is recommended that a strategy of using complementary biometric and behavioural approaches be adopted to best understand participants’ adherence to ARV-based ring products in clinical trials.

Safety, Acceptability and Adherence of Dapivirine Vaginal Ring in a Microbicide Clinical Trial Conducted in Multiple Countries in Sub-Saharan Africa

Background

This was the first microbicide trial conducted in Africa to evaluate an antiretroviral-containing vaginal ring as an HIV prevention technology for women.

Objectives

The trial assessed and compared the safety, acceptability and adherence to product use of a 4-weekly administered vaginal ring containing the antiretroviral microbicide, dapivirine, with a matching placebo ring among women from four countries in sub-Saharan Africa.

Methods

280 Healthy, sexually active, HIV-negative women, aged 18 to 40 years were enrolled with 140 women randomised to a dapivirine vaginal ring (25 mg) and 140 women to a matching placebo ring, inserted 4-weekly and used over a 12-week period. Safety was evaluated by pelvic examination, colposcopy, clinical laboratory assessments, and adverse events. Blood samples for determination of plasma concentrations of dapivirine were collected at Weeks 0, 4 and 12. Residual dapivirine levels in returned rings from dapivirine ring users were determined post-trial. Participant acceptability and adherence to ring use were assessed by self-reports.

Results

No safety concerns or clinically relevant differences were observed between the dapivirine and placebo ring groups. Plasma dapivirine concentrations immediately prior to ring removal were similar after removal of the first and third ring, suggesting consistent ring use over the 12-week period. No clear relationship was observed between the residual amount of dapivirine in used rings and corresponding plasma concentrations. Self-reported adherence to daily use of the vaginal rings over the 12-week trial period was very high. At the end of the trial, 96% of participants reported that the ring was usually comfortable to wear, and 97% reported that they would be willing to use it in the future if proven effective.

Conclusions

The dapivirine vaginal ring has a favourable safety and acceptability profile. If proven safe and effective in large-scale trials, it will be an important component of combination HIV prevention approaches for women.

Trial Registration

ClinicalTrials.gov NCT01071174

Divergent adherence estimates with pharmacokinetic and behavioural measures in the MTN-003 (VOICE) study

INTRODUCTION

In the Microbicide Trial Network MTN-003 (VOICE) study, a Phase IIB pre-exposure prophylaxis trial of daily oral or vaginal tenofovir (TFV), product adherence was poor based on pharmacokinetic (PK) drug detection in a random subsample. Here, we sought to compare behavioural and PK measures of adherence and examined correlates of adherence misreporting.

METHODS

We included participants with PK and behavioural data from VOICE random subsample. Behavioural assessments included face-to-face interviews (FTFI), audio computer-assisted self-interviewing (ACASI) and pharmacy-returned product counts (PC). TFV concentrations < 0.31 ng/mL in plasma (oral group) and < 8.5 ng/swab in vaginal group were defined as "PK non-adherent." Logistic regression models were fit to calculate the combined predictive ability of the behavioural measures as summarized by area under the curve (AUC). Baseline characteristics associated with over-reporting daily product use relative to PK measures was assessed using a Generalized Linear Mixed Model.

RESULTS

In this random adherence cohort of VOICE participants assigned to active products, (N = 472), PK non-adherence was 69% in the oral group (N = 314) and 65% in the vaginal group (N = 158). Behaviourally, ≤ 10% of the cohort reported low/none use with any behavioural measure and accuracy was low (≤ 43%). None of the regression models had an AUC > 0.65 for any single or combined behavioural measures. Significant (p < 0.05) correlates of over-reporting included being very worried about getting HIV and being unmarried for the oral group; whereas for the vaginal group, being somewhat worried about HIV was associated with lower risk of over-reporting.

CONCLUSIONS

PK measures indicated similarly low adherence for the oral and vaginal groups. No behavioural measure accurately predicted PK non-adherence. Accurate real-time measures to monitor product adherence are urgently needed.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00705679.

Dose Frequency Ranging Pharmacokinetic Study of Tenofovir-Emtricitabine After Directly Observed Dosing in Healthy Volunteers to Establish Adherence Benchmarks (HPTN 066)

Oral preexposure prophylaxis (PrEP) trials report disparate efficacy attributed to variable adherence. HPTN 066 was conducted to establish objective, quantitative benchmarks for discrete, regular levels of adherence using directly observed dosing of tenofovir (TFV) disoproxil fumarate (TDF)/emtricitabine (FTC). Healthy, HIV-uninfected men and women were randomized to one of four oral regimens of fixed-dose TDF 300 mg/FTC 200 mg tablet for 5 weeks with all doses observed: one tablet weekly (one/week), one tablet twice weekly (two/week), two tablets twice weekly (four/week), or one tablet daily (seven/week). Trough serum TFV and FTC, peripheral blood mononuclear cell (PBMC), and CD4(+) TFV-diphosphate (TFV-DP) and FTC-triphosphate (FTC-TP) concentrations were determined throughout dosing and 2 weeks after the last dose. Rectosigmoidal, semen, and cervicovaginal samples were collected for drug assessment at end of dosing and 2 weeks later in a subset of participants. The 49 enrolled participants tolerated the regimens well. All regimens achieved steady-state concentrations by the second dose for serum TFV/FTC and by 7 days for PBMC TFV-DP/FTC-TP. Steady-state median TFV-DP predose concentrations demonstrated dose proportionality: one/week 1.6 fmol/10(6) PBMCs, two/week 9.1, four/week 18.8, seven/week, 36.3. Further, TFV-DP was consistently quantifiable 2 weeks after the last dose for the ≥4/week regimens. Adherence benchmarks were identified using receiver operating characteristic curves, which had areas under the curve ≥0.93 for all analytes in serum and PBMCs. Intersubject and intrasubject coefficients of variation (%CV) ranged from 33% to 63% and 14% to 34%, respectively, for all analytes in serum and PBMCs. Steady-state PBMC TFV-DP was established earlier and at lower concentrations than predicted and was the only analyte demonstrating predose concentration dose proportionality. Steady-state daily dosing serum TFV and PBMC TFV-DP was consistent with highly effective PrEP clinical trials. HPTN 066 provides adherence benchmarks for oral TFV/FTC regimens to assist interpreting study outcomes.

Disclosure of pharmacokinetic drug results to understand nonadherence

OBJECTIVES

In VOICE, a phase IIB trial of daily oral and vaginal tenofovir for HIV prevention, at least 50% of women receiving active products had undetectable tenofovir in all plasma samples tested. MTN-003D, an ancillary study using in-depth interviews (IDIs) and focus group discussions (FGDs), together with retrospective disclosure of plasma tenofovir pharmacokinetic results, explored adherence challenges during VOICE.

METHODS

We systematically recruited participants with pharmacokinetic data (median six plasma samples), categorized as low (0%, N = 79), inconsistent (1-74%, N = 28) or high (≥75%; N = 20) on the basis of frequency of tenofovir detection. Following disclosure of pharmacokinetic results, reactions were captured and adherence challenges systematically elicited; IDIs and FGDs were audio-recorded, transcribed, coded and thematically analysed.

RESULTS

We interviewed 127 participants from South Africa, Uganda and Zimbabwe. The most common reactions to pharmacokinetic results included surprise (41%; low pharmacokinetic), acceptance (39%; inconsistent pharmacokinetic) and happiness (65%; high pharmacokinetic). On the basis of participants' explanations, we developed a typology of adherence patterns: noninitiation, discontinuation, misimplementation (resulting from visit-driven use, variable taking, modified dosing or regimen) and adherence. Fear of product side effects/harm was a frequent concern, fuelled by stories shared among participants. Although women with high pharmacokinetic levels reported similar concerns, several described strategies to overcome challenges. Women at all pharmacokinetic levels suggested real-time drug monitoring and feedback to improve adherence and reporting.

CONCLUSION

Retrospective provision of pharmacokinetic results seemingly promoted candid discussions around nonadherence and study participation. The effect of real-time drug monitoring and feedback on adherence and accuracy of reporting should be evaluated in trials.

Comparison of visual and ultraviolet light inspection versus DNA/protein biomarkers to assess product adherence with vaginal microbicide applicators

BACKGROUND

Objective biomarkers of product use and protocol compliance are urgently needed. We compared the sensitivity and specificity of DNA and protein-based biomarkers, obtained from used vaginal gel applicators, to visual inspection of those applicators under ambient light (visual inspection of returned applicator [VIRA]) and ultraviolet light (UVL).

METHODS

Forty women inserted hydroxyethylcellulose placebo gel vaginal applicators under direct observation. Applicators were evaluated by VIRA, UVL, and DNA/protein-based methods at 2 time points: within 7 days of the visit and after storing applicators for approximately 30 days. Semen biomarkers were assayed from vaginal swabs and returned applicators.

RESULTS

The overall sensitivity and specificity of DNA and protein-based biomarkers in determining vaginal insertion versus sham handling of returned applicators were 98.3% and 100%, respectively, at both 7- and 30-day evaluations. The overall sensitivity and specificity of VIRA at 7 and 30 days after collection were significantly lower than those of DNA and protein-based biomarkers. Ultraviolet light inspection also had significantly lower overall sensitivity and overall specificity compared with DNA and protein biomarkers. The sensitivity of DNA and protein-based biomarkers for detecting insertion of wiped applicators was 95%, whereas the sensitivity of VIRA (range of 24%-28%) and UVL inspection (range, 38%-84%) was low for this subset. It was feasible to obtain semen biomarkers from vaginal swabs and returned used applicators.

CONCLUSIONS

DNA and protein-based biomarkers offer significantly higher sensitivity and specificity compared with VIRA and UVL assessment. The accuracy of these objective biomarkers is maintained despite storage of returned products for approximately 30 days and under conditions potentially modeling field use.

An interdisciplinary framework for measuring and supporting adherence in HIV prevention trials of ARV-based vaginal rings

INTRODUCTION

Product adherence and its measurement have emerged as a critical challenge in the evaluation of new HIV prevention technologies. Long-acting ARV-based vaginal rings may simplify use instructions and require less user behaviour, thereby facilitating adherence. One ARV-based ring is in efficacy trials and others, including multipurpose rings, are in the pipeline. Participant motivations, counselling support and measurement challenges during ring trials must still be addressed. In previous HIV prevention trials, this has been done largely using descriptive and post-hoc methods that are highly variable and minimally evaluated. We outline an interdisciplinary framework for systematically investigating promising strategies to support product uptake and adherence, and to measure adherence in the context of randomized, blinded clinical trials.

DISCUSSION

The interdisciplinary framework highlights the dual use of adherence measurement (i.e. to provide feedback during trial implementation and to inform interpretation of trial findings) and underscores the complex pathways that connect measurement, adherence support and enacted adherence behaviour. Three inter-related approaches are highlighted: 1) adherence support - sequential efforts to define motivators of study product adherence and to develop, test, refine and evaluate adherence support messages; 2) self-reported psychometric measures - creation of valid and generalizable measures based in easily administered scales that capture vaginal ring use with improved predictive ability at screening, baseline and follow-up that better engage participants in reporting adherence; and 3) more objective measurement of adherence - real-time adherence monitoring and cumulative measurement to correlate adherence with overall product effectiveness through innovative designs, models and prototypes using electronic and biometric technologies to detect ring insertion and/or removal or expulsion. Coordinating research along these three pathways will result in a comprehensive approach to product adherence within clinical trials.

CONCLUSIONS

Better measurement of adherence will not, by itself, ensure that future effectiveness trials will be able to address the most basic question: if the product is used per instructions, will it prevent HIV transmission? The challenges to adherence measurement must be addressed as one component of a more integrated system that has as its central focus adherence as a behaviour emerging from the social context of the user.

Impact of an adherence intervention on the effectiveness of tenofovir gel in the CAPRISA 004 trial

High adherence is important in microbicide trials, but no adherence interventions to date have demonstrated empiric improvements in microbicide adherence or effectiveness. Approximately midway during the CAPRISA 004 trial, we implemented a novel adherence intervention (Adherence Support Program-ASP), based on an Information-Motivation-Behavioral Skills model and incorporating a Motivational Interviewing approach. We assessed the impact of the ASP on adherence and tenofovir gel effectiveness using a before-and-after comparison. Of the 889 women in the trial, 774 contributed 486.1 women-years of follow-up pre-ASP and 828 contributed 845.7 women-years of follow-up post-ASP. Median adherence rose from 53.6 % pre-ASP to 66.5 % post-ASP. Detectable tenofovir levels increased from 40.6 % pre-ASP to 62.5 % post-ASP in 64 women who had paired tenofovir drug samples. Gel effectiveness improved post-ASP; HIV incidence in the tenofovir gel arm was 24 % lower pre-ASP compared to 47 % lower post-ASP. Following implementation of the ASP, microbicide adherence improved with a concomitant increase in the effectiveness of tenofovir gel.

Use of the dye stain assay and ultraviolet light test for assessing vaginal insertion of placebo-filled applicators before and after sex

BACKGROUND

Applicator dye staining and ultraviolet (UV) light have been used in trials to measure adherence, but not in the setting of before and after sex gel dosing (BAT-24). This study was designed to determine if semen or presex gel dosing impacts the sensitivity and specificity of a dye stain assay (DSA) for measuring vaginal insertion of placebo-filled applicators with BAT-24 dosing.

METHODS

Healthy monogamous couples received Microlax-type applicators (Tectubes, Åstorp, Sweden) filled with hydroxyethylcelluose placebo gel. Women were instructed to vaginally insert 1 dose of gel before and a second dose after sex and to return applicators within 48 hours after sex. Applicators were stained to detect semen, followed by UV then DSA, and scored by 2 readers. Positive and negative controls were randomly included in applicator batches.

RESULTS

Fifteen couples completed the study. Each woman returned at least 6 applicators over a 30-day period. The sensitivity for insertion of postsex applicators was higher for UV (97%) compared with DSA (90%), and the specificity was similar (≥96%). For presex applicators, the sensitivity and specificity were higher for DSA (100%) compared with UV testing (87% sensitivity, 96% specificity). Among returned postsex applicators, 95% tested positive by UV compared with 87% by DSA. Agreement between readers was significantly better on the presex applicators for DSA than for UV, and for postsex readings, agreement was less than half that for UV, although the results were not statistically significant.

CONCLUSIONS

Applicator tests are feasible for measuring adherence in trials with gel dosing before and after sex.

Evaluation of 3 approaches for assessing adherence to vaginal gel application in clinical trials

BACKGROUND

Accurate measurement of adherence to product use is an ongoing challenge in microbicide trials.

METHODS

We compared adherence estimates using 2 applicator tests (a dye stain assay [DSA] and an ultraviolet light assay [UVA]), the Wisebag (an applicator container that electronically tracks container openings), and self-reported adherence (ability, frequency, and percent missed doses). Healthy, HIV-negative, nonpregnant US women aged 23 to 45 years received a Wisebag and 32 applicators filled with placebo gel were instructed to insert 1 applicator daily for 30 days, returned the Wisebag and all applicators, and completed an exit interview. Emptied applicators were tested by UVA and then DSA, and scored by 2 blinded readers. Positive and negative controls were randomly included in applicator batches.

RESULTS

Among 42 women enrolled, 39 completed the study. Both DSA and UVA yielded similar sensitivity (97% and 95%) and specificity (79% and 79%). Two participants had fully inoperable Wisebags, and 9 had partially inoperable Wisebags. The proportion of participants considered to have high adherence (≥80%) varied: 43% (Wisebag), 46% (UVA), 49% (DSA), and 62% to 82% (self-reports). For estimating high adherence, Wisebag had a sensitivity of 76% (95% confidence interval, 50%-93%) and a specificity of 85% (95% confidence interval, 62%-97%) compared with DSA. Although 28% of participants reported forgetting to open the Wisebag daily, 59% said that it helped them remember gel use.

CONCLUSIONS

Dye stain assay and UVA performed similarly. Compared with these tests, self-reports overestimated and Wisebag underestimated adherence. Although Wisebag may encourage gel use, the applicator tests currently seem more useful for measuring use in clinical trials.

Summary measures of adherence using pill counts in two HIV prevention trials: the need for standardisation in reporting

For trials of user-dependent HIV prevention products, accurate adherence measurements are essential to interpret and compare results across trials. We used pill count data from two recent HIV prevention trials of herpes simplex virus type 2 (HSV-2) suppression, to show that estimates of adherence vary substantially depending on assumptions that are made in analysing pill count data. We associate calculated adherence with biological markers of anti-HSV-2 activity. In both trials, calculated adherence varied considerably, depending on the summary measure used, and the handling of intervals with apparent ‘over-adherence’ (fewer pills returned than expected), and unreturned pills. Intervals of apparent over-adherence were associated with reduced antiviral effects on biological markers of herpes reactivation, indicating these are likely to represent periods of non-adherence. Our results demonstrate the clear need for standardisation in reporting of adherence data that are based on pill counts.

Development of dapivirine vaginal ring for HIV prevention

In the continuing effort to develop effective HIV prevention methods for women, a vaginal ring containing the non-nucleoside reverse transcriptase inhibitor dapivirine is currently being tested in two safety and efficacy trials. This paper reviews dapivirine ring's pipeline development process, including efforts to determine safe and effective dosing levels as well as identify delivery platforms with the greatest likelihood of success for correct and consistent use. Dapivirine gel and other formulations were developed and tested in preclinical and clinical studies. Multiple vaginal ring prototypes were also tested, resulting in the current ring design as well as additional designs under consideration for future testing. Efficacy results from clinical trials are expected in 2015. Through ongoing consultations with national regulatory authorities, licensure requirements for dapivirine vaginal ring approval have been defined. This article is based on a presentation at the "Product Development Workshop 2013: HIV and Multipurpose Prevention Technologies," held in Arlington, Virginia on February 21-22, 2013. It forms part of a special supplement to Antiviral Research.

Microbicide clinical trial adherence: insights for introduction

After two decades of microbicide clinical trials it remains uncertain if vaginally- delivered products will be clearly shown to reduce the risk of HIV infection in women and girls. Furthermore, a microbicide product with demonstrated clinical efficacy must be used correctly and consistently if it is to prevent infection. Information on adherence that can be gleaned from microbicide trials is relevant for future microbicide safety and efficacy trials, pre-licensure implementation trials, Phase IV post-marketing research, and microbicide introduction and delivery. Drawing primarily from data and experience that has emerged from the large-scale microbicide efficacy trials completed to-date, the paper identifies six broad areas of adherence lessons learned: (1) Adherence measurement in clinical trials, (2) Comprehension of use instructions/Instructions for use, (3) Unknown efficacy and its effect on adherence/Messages regarding effectiveness, (4) Partner influence on use, (5) Retention and continuation and (6) Generalizability of trial participants' adherence behavior. Each is discussed, with examples provided from microbicide trials. For each of these adherence topics, recommendations are provided for using trial findings to prepare for future microbicide safety and efficacy trials, Phase IV post-marketing research, and microbicide introduction and delivery programs.