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

Adherence to Pre-Exposure Prophylaxis in Adolescents and Young Adults: A Systematic Review and Meta-Analysis

This meta-analysis synthesized the proportion of adolescents and young adults (AYAs) who are adherent to pre-exposure prophylaxis (PrEP) and factors moderating adherence. A systematic search was conducted of studies published through May 2020 using PubMed, PsycInfo, Cochrane, EMBASE, and CINAHL. Included studies reported the proportion of AYAs (mean age ≤ 29 years) who were PrEP adherent. PrEP adherence was meta-analyzed using random-effects models. Secondary analyses evaluated potential moderating variables. A total of 41 individual samples, from 29 studies, of 8,679 AYA (weighted average age = 23.8 years) were synthesized. The proportion of AYA who met study-defined thresholds for PrEP adherence was .64 (95% confidence interval .57-.71) across studies. Subgroup analyses revealed that adherence was lower in young cisgender women (.46) than young men who have sex with men (.65) and serodiscordant heterosexual couples (.98). Adherence was higher in studies initiated after 2012 (.70) than earlier studies (.47). No differences based on participant age, country, or strategies to promote adherence were found. Across published studies to date, 64% of AYA demonstrate adequate PrEP adherence. Findings can be used to guide PrEP adherence interventions and also provide directions for future research on PrEP among AYA.

Integration of HIV Prevention With Sexual and Reproductive Health Services: Evidence for Contraceptive Options and HIV Outcomes Study Experience of Integrating Oral Pre-exposure HIV Prophylaxis in Family Planning Services in Lusaka, Zambia

The WHO guideline on the integration of family planning (FP) and pre-exposure HIV prophylaxis (PrEP) to enhance the health of women and adolescent girls is reflected in the Zambia Consolidated Guidelines for Treatment and Prevention of HIV Infection, 2020. There is however a dearth of data on the integration of PrEP and FP in Zambia. We describe the integration of oral PrEP in FP services using the Evidence for Contraceptive Options and HIV Outcomes (ECHO) study experience at Kamwala District Health Center in Lusaka, Zambia. The provision of oral PrEP at Kamwala started in October 2017, lasting for ~11 months, and utilized the model where initial processes to offer PrEP were on-site followed by off-site referral to laboratory and PrEP provider services. The characteristics of 658 women who enrolled in ECHO at Kamwala are representative of women accessing FP services in Lusaka. About 644 of the enrollees were offered oral PrEP. The proportion of women accepting PrEP was low at 1.08% and the proportion of study visits at which PrEP was requested was also low at 0.57%. Those who accepted PrEP were above 20 years old, married, with at least primary education, sexual behavior, and risk comparable to decliners. The ECHO study experience indicates that the setup and integration of oral PrEP and FP services are feasible in the setting. However, uptake of PrEP was very low. Possible contributory factors were as follows: (1) timing of introduction of PrEP midway in the study, (2) PrEP being a new intervention, (3) challenges of autonomy of young women to include a daily pill into their lives and anticipated challenges to adherence because of fear of adverse events, (4) possible underdetermined risk due to use of an unvalidated risk assessment tool and assessment by health care provider vs. self-assessment, and (5) extra layer of challenges to negotiate due to needing for off-site referrals. Following these findings, we conclude that further research through demonstration projects of integration of oral PrEP and FP may provide solutions to low uptake. This information is critical for scaling up of integration HIV prevention services and sexual and reproductive health (SRH) services.

Factors Affecting Pre-Exposure Prophylaxis Implementation for Women in the United States: A Systematic Review

Oral HIV pre-exposure prophylaxis (PrEP) is a highly effective pill that HIV-negative individuals can take once daily to prevent HIV infection. Although PrEP is a private, user-controlled method that empowers women to protect themselves without relying on a partner's behavior, women's PrEP use has been extremely low. We systematically reviewed the literature to identify and summarize factors that may be affecting PrEP implementation for women in the United States. We conducted a search of the Centers for Disease Control and Prevention HIV/AIDS Prevention Research Synthesis Project database (MEDLINE, EMBASE, and CINAHL) and PubMed to identify peer-reviewed studies published between January 2000 and April 2018 that reported U.S. women's or health care providers' PrEP knowledge or awareness, willingness to use or prescribe, attitudes, barriers and facilitators to use or prescription, or PrEP adherence and discontinuation influences. Thirty-nine studies (26 women, 13 providers) met the eligibility criteria. In these studies, 0%-33% of women had heard of PrEP. Between 51% and 97% of women were willing to try PrEP, and 60%-92% of providers were willing to prescribe PrEP to women. Implementation barriers included access, cost, stigma, and medical distrust. Three studies addressed adherence or discontinuation. PrEP knowledge is low among women and providers. However, women and providers generally have positive views when aware of PrEP, including a willingness to use or prescribe PrEP to women. Most of the implementation barriers highlighted in studies were social or structural factors (e.g., access). Additional studies are needed to address research gaps, including studies of PrEP adherence and discontinuation.

Understanding women's motivations to participate in MTN-003/VOICE, a phase 2b HIV prevention trial with low adherence

BACKGROUND

In biomedical prevention trials, correct and consistent use of the investigational product is crucial to determine efficacy. Product adherence in VOICE, a phase 2B randomized trial of a vaginal gel and oral tablets for HIV prevention, was low (~ 34%), yet self-reported adherence and retention was high (> 90%). This analysis from VOICE-D, a post-trial qualitative ancillary study, explores motivations to participate in VOICE, and possible sources of misalignment between the stated priorities of the trial and the participants.

METHODS

VOICE-D enrolled 171 former VOICE participants to investigate, among other things, reasons for joining and remaining in the trial. Local language in-depth interviews and focus groups were transcribed and translated into English and coded and analyzed using NVivo. Data on motivation to join obtained from a VOICE termination visit survey of 106 participants were also analyzed to corroborate the VOICE-D findings.

RESULTS

Participants primarily participated for personal health benefits (e.g. free healthcare and HIV testing) and reported remaining enrolled from a sense of commitment to the trial. Altruistic motivations were the most commonly stated motivation on the termination visit survey; qualitatively, many of those stating altruistic reasons also desired personal health benefits. Joining for financial reimbursement was not commonly mentioned. Social networks influenced recruitment and spread therapeutic misconception.

CONCLUSIONS

Women's participation for personal health benefits highlighted their desire to monitor their HIV risk and overall health. Helping participants view use of investigational products as improving social capital and reminding participants of their study responsibilities may improve trial outcomes. Understanding the reasons for participating in studies will help to ensure alignment between priorities of researchers and participants.

TRIAL REGISTRATION

NCT02358616 ; Posted February 9, 2015, retrospectively registered.

Associations between perceived barriers and benefits of using HIV pre-exposure prophylaxis and medication adherence among men who have sex with men in Western China

BACKGROUND

To investigate the associations between the perceived barriers and benefits of using HIV pre-exposure prophylaxis medication, including worries about the side effects, disliking taking drugs, perceived burden of taking medication, positive expectations as to the efficacy of the drugs, favourable doctor-patient relationships, and medication adherence among men who have sex with men (MSM) to provide a target for improving medication adherence and reducing HIV infection among MSM.

METHODS

MSM were recruited in western China from April 2013 to October 2014, administered oral tenofovir (TDF) daily and followed up every 12 weeks for 2 years. At each follow-up, the medication rate was calculated based on the self-reported number of missed doses over 2 weeks, and then, the medication adherence was evaluated. The barriers and benefits perceived during medication were obtained by a self-administered questionnaire, and their effects on medication adherence were analysed by linear mixed models.

RESULTS

A total of 411 participants were enrolled in this study, and 1561 follow-up observation points were obtained. The average medication rate was 0.62 ± 0.37, and the medication rate increased with longer follow-up (P < 0.05). The medication rate was higher among MSM who were divorced (compared to those who were unmarried, P < 0.0001). MSM with more positive expectations as to the efficacy of the drugs showed higher rates of medication (P < 0.0001), while those who were more worried about side effects had a lower medication rate (P = 0.0208). In contrast, the dislike of taking the drugs and the burden perceived during medication had no effects on the actual medication rate of taking TDF (P > 0.05).

CONCLUSION

How to obtain and maintain high medication adherence among MSM is the key to the PrEP intervention strategy for effective reduction of HIV infection. For MSM in China, we should deepen their understanding of the effectiveness and safety of PrEP and increase their confidence in PrEP, thereby improving their medication adherence.

TRIAL REGISTRATION

ChiCTR-TRC-13003849 . Registered on 24/06/2013.

Technological methods to measure adherence to antiretroviral therapy and preexposure prophylaxis

PURPOSE OF REVIEW

The WHO's Consolidated Guidelines (2016) call for research on improved methods to proactively monitor adherence and identify those individuals who have the greatest needs for adherence support. This review aims to elucidate the latest technologies available to measure adherence to HIV antiretroviral therapy and preexposure prophylaxis against HIV infection and present their utility in various settings and populations.

RECENT FINDINGS

Within the last few years, advances have been made in the features of existing technology to measure adherence (real-time electronic adherence measurements), additional approaches have been developed (digital medicine systems) and improved (short message service surveys), and point of care testing for pharmacokinetic measures are under development.

SUMMARY

Technology advances in adherence measurement are promising for improved accuracy and, in some cases, the ability to intervene with adherence challenges in real time. This progress will greatly further our understanding of adherence behavior, as well as the ability to effectively link interventions with individuals who need them, thus maximizing the clinical and public health benefits of both antiretroviral therapy and preexposure prophylaxis.

Historical development of vaginal microbicides to prevent sexual transmission of HIV in women: from past failures to future hopes

Infection with human immunodeficiency virus (HIV) remains a global public health concern and is particularly serious in low- and middle-income countries. Widespread sexual violence and poverty, among other factors, increase the risk of infection in women, while currently available prevention methods are outside the control of most. This has driven the study of vaginal microbicides to prevent sexual transmission of HIV from men to women in recent decades. The first microbicides evaluated were formulated as gels for daily use and contained different substances such as surfactants, acidifiers and monoclonal antibodies, which failed to demonstrate efficacy in clinical trials. A gel containing the reverse transcriptase inhibitor tenofovir showed protective efficacy in women. However, the lack of adherence by patients led to the search for dosage forms capable of releasing the active principle for longer periods, and hence to the emergence of the vaginal ring loaded with dapivirine, which requires a monthly application and is able to reduce the sexual transmission of HIV. The future of vaginal microbicides will feature the use of alternative dosage forms, nanosystems for drug release and probiotics, which have emerged as potential microbicides but are still in the early stages of development. Protecting women with vaginal microbicide formulations would, therefore, be a valuable tool for avoiding sexual transmission of HIV.

Packing Polymorphism of Dapivirine and Its Impact on the Performance of a Dapivirine-Releasing Silicone Elastomer Vaginal Ring

A silicone elastomer vaginal ring providing sustained release over 28 days of the anti-retroviral microbicide dapivirine has recently completed phase III clinical testing and showed moderate protection against HIV acquisition. In support of the product licensure program, we report the impact of dapivirine packing polymorphism on the thermal and solubility characteristics of dapivirine and on the in vitro performance of the 25 mg dapivirine ring product. This is the first time that polymorphism has been reported for a drug-releasing vaginal ring product. Thermal, particle size, powder X-ray diffraction, and thermodynamic solubility analyses of dapivirine polymorphic forms I and IV, both of which are persistent at room temperature and with form I being the thermodynamically stable form, were conducted for both micronized and non-micronized materials. No significant differences in solubility between DPV forms I and IV were observed in media commonly used for in vitro release testing. Matrix-type silicone elastomer vaginal rings were manufactured and the impact of dapivirine polymorphism on key in vitro parameters (compression and tensile behavior; content assay; in vitro release; residual content assay) was investigated. The data demonstrate that dapivirine packing polymorphism has no significant impact on in vitro performance of the 25 mg dapivirine vaginal ring.

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.

Adherence and Acceptability of a Multidrug Vaginal Ring for HIV Prevention in a Phase I Study in the United States

We evaluated the adherence and acceptability of a vaginal ring containing dapivirine, maraviroc, or both drugs for 28 days during a Phase I placebo-controlled trial in 48 HIV-negative sexually abstinent U.S. women aged 18-40. Adherence was assessed weekly by clinical interview and computer-assisted self-interviewing; acceptability assessment occurred at the last product-use visit. Study retention was 98 % (47/48); 94 % (45/48) reported being fully adherent with ring use during the 28-day period. Two participants experienced the ring partially coming out. Analysis was blinded and behavioral data were combined across study groups. Most women reported being very comfortable having the ring in their vagina; 44 % preferred continuous use, whereas 51 % had no preference compared to episodic use. Although a range of minor ring concerns were expressed, few were actually experienced. High adherence to and acceptability of this vaginal ring in this Phase I trial contributes to its promise as a sustained mechanism for multidrug vaginal microbicide delivery.

Superior Efficacy of a Human Immunodeficiency Virus Vaccine Combined with Antiretroviral Prevention in Simian-Human Immunodeficiency Virus-Challenged Nonhuman Primates

Although vaccines and antiretroviral (ARV) prevention have demonstrated partial success against human immunodeficiency virus (HIV) infection in clinical trials, their combined introduction could provide more potent protection. Furthermore, combination approaches could ameliorate the potential increased risk of infection following vaccination in the absence of protective immunity. We used a nonhuman primate model to determine potential interactions of combining a partially effective ARV microbicide with an envelope-based vaccine. The vaccine alone provided no protection from infection following 12 consecutive low-dose intravaginal challenges with simian-HIV strain SF162P3, with more animals infected compared to naive controls. The microbicide alone provided a 68% reduction in the risk of infection relative to that of the vaccine group and a 45% reduction relative to that of naive controls. The vaccine-microbicide combination provided an 88% reduction in the per-exposure risk of infection relative to the vaccine alone and a 79% reduction relative to that of the controls. Protected animals in the vaccine-microbicide group were challenged a further 12 times in the absence of microbicide and demonstrated a 98% reduction in the risk of infection. A total risk reduction of 91% was observed in this group over 24 exposures (P = 0.004). These important findings suggest that combined implementation of new biomedical prevention strategies may provide significant gains in HIV prevention.

IMPORTANCE There is a pressing need to maximize the impact of new biomedical prevention tools in the face of the 2 million HIV infections that occur each year. Combined implementation of complementary biomedical approaches could create additive or synergistic effects that drive improved reduction of HIV incidence. Therefore, we assessed a combination of an untested vaccine with an ARV-based microbicide in a nonhuman primate vaginal challenge model. The vaccine alone provided no protection (and may have increased susceptibility to a simian-HIV vaginal challenge), while the microbicide reduced the infection risk compared to that of vaccinated and naive animals. Importantly, the combined interventions provided the greatest level of protection, which was sustained following withdrawal of the microbicide. The data suggest that provision of ARV prophylaxis during vaccination reduces the potential for unexpected increased risks of infection following immunization and augments vaccine efficacy. These findings are important for the potential adoption of ARV prophylaxis as the baseline intervention for future HIV/AIDS vaccines.

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.