Microbicide acceptability research: recent findings and evolution across phases of product development:

Acceptability Assessment in HIV Prevention and Treatment Intervention and Service Delivery Research: A Systematic Review and Qualitative Analysis

We reviewed the literature on the assessment of acceptability of HIV prevention and treatment interventions and service delivery strategies. Following PRISMA guidelines, we screened 601 studies published from 2015 to 2020 and included 217 in our review. Of 384 excluded studies, 21% were excluded because they relied on retention as the sole acceptability indicator. Of 217 included studies, only 16% were rated at our highest tier of methodological rigor. Operational definitions of acceptability varied widely and failed to comprehensively represent the suggested constructs in current acceptability frameworks. Overall, 25 studies used formal quantitative assessments (including four adapted measures used in prior studies) and six incorporated frameworks of acceptability. Findings suggest acceptability assessment in recent HIV intervention and service delivery research lacks harmonization and rigor. We offer guidelines for best practices and future research, which are timely and critical in this era of informed choice and novel options for HIV prevention and treatment.

Pregnant and breastfeeding women's prospective acceptability of two biomedical HIV prevention approaches in Sub Saharan Africa: A multisite qualitative analysis using the Theoretical Framework of Acceptability

HIV infection during pregnancy and breastfeeding has implications for maternal health. Between May- November 2018, we explored prospective acceptability of two novel HIV Pre-exposure Prophylaxis (PrEP) products, oral pills and vaginal rings, through focus group discussions with 65 pregnant and breastfeeding women in Malawi, South Africa, Uganda, Zimbabwe. Qualitative analysis was completed, guided by the Theoretical Framework of Acceptability (TFA). First, a deductive thematic analysis was applied to relevant coded data, into the seven TFA constructs (Affective Attitude; Burden; Ethicality, Intervention Coherence; Opportunity Costs; Perceived Effectiveness; Self-efficacy). Next, an iterative analysis was completed to generate themes within each of the TFA constructs. Women’s positive attitudes towards daily oral PrEP highlighted the familiarity of taking pills, understanding the purpose of taking pills, and the perception that it is an effective method to protect mothers and babies from HIV during pregnancy and breastfeeding. Women emphasized the ease of using the ring given its monthly duration that lowers burden on the user, its discreetness and invisibility once in place. The TFA analysis highlighted how acceptability of both methods could be enhanced by focusing on perceptions of the end users (i.e. the women) and not just the products themselves. This approach provided insights into how to refine the intervention materials and plans for implementation.

The influence of social constructs of hegemonic masculinity and sexual behaviour on acceptability of vaginal microbicides in Zambia

Vaginal microbicides are heralded as a woman's HIV prevention method. This study, conducted in a microbicide clinical trial setting in Zambia, explored how the social construction of masculinity and sexual behaviour influenced the acceptability of vaginal microbicides. The data were generated from 18 In-depth Interviews and 8 Focus Group Discussions. The data were analysed thematically. The study found that hegemonic masculinity influenced the use of vaginal microbicides positively and negatively, in multiple ways including: decision to initiate gel use, autonomous use of the gel, and consistent use of the gel. Men were seen as heads of households and decision-makers who approved their partners' intentions to initiate gel use. Autonomous gel use by women was not supported because it challenged men's dominant position in sexual matters and at a family level. The socially accepted notion that men engaged in multiple sexual relationships also influenced women's decision to use the gel. Sustained gel use depended on the perceived effect of the gel on men's sexual desires, sexual performance, fertility, and sexual behaviour. This study suggests that acceptability of microbicides partially lies within the realm of men, with use constrained and dictated by cultural constructs and practice of masculinity and gender.

Lessons for Rectal Microbicide Development From an Acceptability Trial of a Placebo Gel Applied Prior to Receptive Anal Intercourse

Rectal microbicides, formulated as a gel to be applied before and/or after intercourse, are promising HIV prevention agents and are now in Phase II trials. However, both an optimal formulation and a practical delivery system are needed to ensure that the target population will use the product once efficacy is demonstrated. The precise dynamics of lubricant application by gay and bisexual men who practice anal sex and the qualities they seek in these products are underexplored. As part of a Phase I microbicide acceptability and adherence study conducted in one Puerto Rican and two continental U.S. cities, we recruited 124 young men who have sex with men (YMSM) with a history of unprotected receptive anal intercourse (RAI) and provided them with 40 rectal applicators containing a placebo gel to use prior to RAI during a 12-week period as a proxy for an eventual rectal microbicide. Ninety-five YMSM completed the trial. Their varied preferences as to product viscosity, durability, residue, and mode of application provide important lessons for the design of a product that will be satisfactory to users. Despite many reservations, the participants used the product frequently and found ways to overcome a range of obstacles. A successful rectal microbicide product may need to be presented in a range of viscosities to attract a broad client base.

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.

Stated product formulation preferences for HIV pre-exposure prophylaxis among women in the VOICE-D (MTN-003D) study

Introduction

The effectiveness of HIV pre-exposure prophylaxis (PrEP) requires consistent and correct product use, thus a deeper understanding of women's stated product formulation preferences, and the correlates of those preferences, can help guide future research. VOICE-D (MTN-003D), a qualitative ancillary study conducted after the VOICE trial, retrospectively explored participants’ tablet and gel use, as well as their preferences for other potential PrEP product formulations.

Methods

We conducted an analysis of quantitative and qualitative data from VOICE-D participants. During in-depth interviews, women were presented with pictures and descriptions of eight potential PrEP product formulations, including the oral tablet and vaginal gel tested in VOICE, and asked to discuss which product formulations they would prefer to use and why. Seven of the original product formulations displayed were combined into preferred product formulation categories based on exploratory factor and latent class analyses. We examined demographic and behavioural correlates of these preferred product formulation categories. In-depth interviews with participants were conducted, coded, and analysed for themes related to product preference.

Results

Of the 68 female participants who completed in-depth interviews (22 South Africa, 24 Zimbabwe, 22 Uganda), median age was 28 (range 21–41), 81% were HIV negative, and 49% were married or living with a partner. Four preferred product formulation categories were identified via exploratory factor analysis: 1) oral tablets; 2) vaginal gel; 3) injectable, implant, or vaginal ring; and 4) vaginal film or suppository. A majority of women (81%) expressed a preference for product formulations included in category 3. Characteristics significantly associated with each preferred product category differed. Attributes described by participants as being important in a preferred product formulation included duration of activity, ease of use, route of administration, clinic- versus self-administration, and degree of familiarity with product.

Conclusions

While there was interest in a variety of potential PrEP product formulations, a majority of VOICE-D participants preferred long-acting methods. More research is needed to gain insight into end-users’ product formulation preference to inform messaging and market segmentation for different PrEP products and resources to invest in products that target populations are most interested in using.

Clinical Trial Number: NCT02358616

Attitudes towards microbicide use for bacterial vaginosis in pregnancy

Background Bacterial vaginosis (BV) is the most common reproductive tract infection (RTI) and is a significant risk factor for preterm birth. Microbicides could be an option for the prevention and treatment of BV in pregnancy, and understanding use of the product will be crucial. The present study explored attitudes of women in the third trimester of pregnancy regarding topical microbicide use for the prevention and treatment of BV.

METHODS

Twenty-six women in their third trimester were interviewed regarding their knowledge and beliefs about RTIs during pregnancy and attitudes concerning the use of topical microbicides for prevention and treatment of BV.

RESULTS

Participants had a mean age of 24.9 years, were largely under-represented minorities and the majority had had past pregnancies. Participants had knowledge and experience with RTIs but not BV. They were open to the use of microbicides for prevention or treatment of BV, but believed that women requiring treatment would be more motivated. Rationales for acceptability were most commonly related to the baby's health. Practical issues that may interfere with use were often, but not always, related to pregnancy. There was a range of attitudes about partner involvement in decision-making and the practicalities of product use.

CONCLUSION

Pregnant women are knowledgeable about RTIs but not necessarily BV. The women in this study found microbicide use acceptable, particularly for treatment. To improve acceptability and use, education would be needed about BV and possible complications, how to overcome practical problems and the value of involving partners in the decision.

Clinical use of vaginal or rectally applied microbicides in patients suffering from HIV/AIDS

Microbicides, primarily used as topical pre-exposure prophylaxis, have been proposed to prevent sexual transmission of HIV. This review covers the trends and challenges in the development of safe and effective microbicides to prevent sexual transmission of HIV Initial phases of microbicide development used such surfactants as nonoxynol-9 (N-9), C13G, and sodium lauryl sulfate, aiming to inactivate the virus. Clinical trials of microbicides based on N-9 and C31G failed to inhibit sexual transmission of HIV. On the contrary, N-9 enhanced susceptibility to sexual transmission of HIV-1. Subsequently, microbicides based on polyanions and a variety of other compounds that inhibit the binding, fusion, or entry of virus to the host cells were evaluated for their efficacy in different clinical setups. Most of these trials failed to show either safety or efficacy for prevention of HIV transmission. The next phase of microbicide development involved antiretroviral drugs. Microbicide in the form of 1% tenofovir vaginal gel when tested in a Phase IIb trial (CAPRISA 004) in a coitally dependent manner revealed that tenofovir gel users were 39% less likely to become HIV-infected compared to placebo control. However, in another trial (VOICE MTN 003), tenofovir gel used once daily in a coitally independent mode failed to show any efficacy to prevent HIV infection. Tenofovir gel is currently in a Phase III safety and efficacy trial in South Africa (FACTS 001) employing a coitally dependent dosing regimen. Further, long-acting microbicide-delivery systems (vaginal ring) for slow release of such antiretroviral drugs as dapivirine are also undergoing clinical trials. Discovering new markers as correlates of protective efficacy, novel long-acting delivery systems with improved adherence in the use of microbicides, discovering new compounds effective against a broad spectrum of HIV strains, developing multipurpose technologies incorporating additional features of efficacy against other sexually transmitted infections, and contraception will help in moving the field of microbicide development forward.

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.

Acceptability in microbicide and PrEP trials: current status and a reconceptualization

PURPOSE OF REVIEW

Assessment of acceptability is a central component of most oral PrEP and microbicide trials. In this paper we review current definitions and frameworks employed in acceptability research, discuss findings from recent studies of product acceptability and summarize trends in acceptability research. We conclude by offering a new framework for investigating product acceptability within clinical trials, one which considers product acceptability to be conceptually distinct from adherence.

RECENT FINDINGS

Although numerous studies have investigated product acceptability, a consensus is lacking regarding the definition and operationalization of the concept. In addition fewer than half of the studies reviewed investigated actual candidate products. To the extent that an overall measure of acceptability is considered, the consensus is that most participants find the products acceptable. However, it is the rare study that investigates whether product adherence is associated with acceptability.

SUMMARY

Given that adherence is critical to the success of clinical trials, it is important to identify the extent to which acceptability is a factor in product usage and to ascertain which dimensions of acceptability - product attributes, dosing regimen, delivery mechanism, use attributes, partner's attitudes, effect of product on the sexual encounter, product-related norms - if any, affect adherence.

Acceptability of potential rectal microbicide delivery systems for HIV prevention: a randomized crossover trial

We assessed the acceptability of three of over-the-counter products representative of potential rectal microbicide (RM) delivery systems. From 2009 to 2010, 117 HIV-uninfected males (79 %) and females (21 %) who engage in receptive anal intercourse participated in a 6-week randomized crossover acceptability trial. Participants received each of three products (enema, lubricant-filled applicator, suppository) every 2 weeks in a randomized sequence. CASI and T-ACASI scales assessed product acceptability via Likert responses. Factor analysis was used to identify underlying factors measured by each scale. Random effects models were fit to examine age and gender effects on product acceptability. Three underlying factors were identified: Satisfaction with Product Use, Sexual Pleasure, and Ease of Product Use. For acceptability, the applicator ranked highest; however, differences between product acceptability scores were greatest among females and younger participants. These findings indicate that RM delivery systems impact their acceptability and should be considered early in RM development to enhance potential use.

Adherence and acceptability in MTN 001: a randomized cross-over trial of daily oral and topical tenofovir for HIV prevention in women

We compared adherence to and acceptability of daily topical and oral formulations of tenofovir (TFV) used as pre-exposure prophylaxis (PrEP) for HIV prevention among women in South Africa, Uganda and the United States. 144 sexually active, HIV-uninfected women participated in a cross-over study of three regimens: oral tablet, vaginal gel, or both. We tested for differences in adherence and evaluated product acceptability. Self-reported adherence for all regimens was high (94 %), but serum TFV concentrations indicated only 64 % of participants used tablets consistently. Most women in the U.S. (72 %) favored tablets over gel; while preferences varied at the African sites (42 % preferred gel and 40 % tablets). Findings indicate a role for oral and vaginal PrEP formulations and highlight the importance of integrating pharmacokinetics-based adherence assessment in future trials. Biomedical HIV prevention interventions should consider geographic and cultural experience with product formulations, partner involvement, and sexual health benefits that ultimately influence use.

"Tell Juliana": acceptability of the candidate microbicide VivaGel® and two placebo gels among ethnically diverse, sexually active young women participating in a phase 1 microbicide study

This study assessed acceptability of the candidate microbicide VivaGel(®) and two placebo gels among 61 sexually active young US and Puerto Rican women at three sites. Participants were randomly assigned to use one of the gels twice per day for 14 days. At trial completion, 59% of the women in the VivaGel(®) group reported being likely to use the gel in the future, whereas 23% were unlikely to use it and 18% were undecided. Participants reported problems with all three gels, including the "universal" placebo containing hydroxyethyl cellulose (HEC). The most frequent complaints were leakage, interference with sexual behavior, and decreased sexual satisfaction. Some of the complaints are not new but remain unresolved. Women's perceived risk of HIV infection may determine whether the gels are used. Users also may want a choice of viscosity. Poor acceptability of vaginal microbicide formulations may result in poor adherence to gel use during efficacy trials and compromise validity of results.

The future role of rectal and vaginal microbicides to prevent HIV infection in heterosexual populations: implications for product development and prevention

OBJECTIVES

To compare the potential impact of rectal (RMB), vaginal (VMB) and bi-compartment (RVMB) (applied vaginally and protective during vaginal and anal intercourse) microbicides to prevent HIV in various heterosexual populations. To understand when a RMB is as useful than a VMB for women practicing anal intercourse (AI).

METHODS

Mathematical model was used to assess the population-level impact (cumulative fraction of new HIV infections prevented (CFP)) of the three different microbicides in various intervention scenarios and prevalence settings. We derived the break-even RMB efficacy required to reduce a female's cumulative risk of HIV infection by the same amount than a VMB.

RESULTS

Under optimistic coverage (fast roll-out, 100% uptake), a 50% efficacious VMB used in 75% of sex acts in population without AI may prevent ∼33% (27, 42%) new total (men and women combined) HIV infections over 25 years. The 25-year CFP reduces to ∼25% (20, 32%) and 17% (13, 23%) if uptake decreases to 75% and 50%, respectively. Similar loss of impact (by 25%-50%) is observed if the same VMB is introduced in populations with 5%-10% AI and for RR(RAI)=4-20. A RMB is as useful as a VMB (ie, break-even) in populations with 5% AI if RR(RAI)=20 and in populations with 15%-20% AI if RR(RAI)=4, independently of adherence as long as it is the same with both products. The 10-year CFP with a RVMB is twofold larger than for a VMB or RMB when AI=10% and RR(RAI)=10.

CONCLUSIONS

Even low AI frequency can compromise the impact of VMB interventions. RMB and RVMB will be important prevention tools for heterosexual populations.

Clinical evaluation of microbicide formulations

The clinical evaluation of microbicide formulations presents variable and interacting challenges. Specific domains of acceptability, pharmacokinetics, and toxicity interact with each other to potentially inhibit or enhance a microbicide's efficacy. Each of these is further influenced by application and use parameters in the relative presence (or absence) of vaginal and/or seminal fluids, ultimately impacting effectiveness. Historically, acceptability of formulation and use parameters, and their concomitant behavioral influences, have been considered separately from pharmacokinetics and toxicity. While independent evaluation of these elements is necessary in some respects, we must acknowledge that this approach is not sufficient for the successful development of microbicides. Each needs to be considered in an integrated clinical evaluation strategy. This article presents the rationale for such an approach. This article forms part of a special supplement covering two presentations on clinical evaluation of microbicides from the symposium on "Recent Trends in Microbicide Formulations" held on 25 and 26 January 2010, Arlington, VA.

Pre-exposure prophylaxis state of the science: empirical analogies for research and implementation

Pre-exposure prophylaxis (PrEP) has the potential to become a powerful biomedical approach to HIV prevention; however, its success depends on behavioral and social factors that may determine its appropriate use. This article is designed to facilitate interdisciplinary empirical analogies relevant to PrEP implementation, reviewing behavioral and social science findings that may provide lessons critical to the success of PrEP as a biomedical-behavioral prevention strategy. As we prepare for the dissemination of new biomedical approaches to HIV prevention, integrating the state of the science across disciplines may result in innovative strategies for implementation that can enhance their success.