Perceptibility and the "Choice Experience": User Sensory Perceptions and Experiences Inform Vaginal Prevention Product Design

Exploring user and stakeholder perspectives from South Africa and Uganda to refine microarray patch development for HIV PrEP delivery and as a multipurpose prevention technology

BACKGROUND

Oral HIV pre-exposure prophylaxis (PrEP) is highly effective, but alternative delivery options are needed to reach more users. Microarray patches (MAPs), a novel drug-delivery system containing micron-scale projections or "microneedles" that deliver drugs via skin, are being developed to deliver long-acting HIV PrEP and as a multipurpose prevention technology to protect from HIV and unintended pregnancy. We explored whether MAP technology could meet user and health system needs in two African countries.

METHODS

Researchers in South Africa and Uganda conducted 27 focus group discussions, 76 mock-use exercises, and 31 key informant interviews to explore perceptions about MAPs and specific features such as MAP size, duration of protection, delivery indicator, and health system fit. Participants included young women and men from key populations and vulnerable groups at high risk of HIV and/or unintended pregnancy, including adolescent girls and young women; female sex workers and men who have sex with these women; and men who have sex with men. In Uganda, researchers also recruited young women and men from universities and the community as vulnerable groups. Key stakeholders included health care providers, sexual and reproductive health experts, policymakers, and youth activists. Qualitative data were transcribed, translated, coded, and analyzed to explore perspectives and preferences about MAPs. Survey responses after mock-use in Uganda were tabulated to assess satisfaction with MAP features and highlight areas for additional refinement.

RESULTS

All groups expressed interest in MAP technology, reporting perceived advantages over other methods. Most participants preferred the smallest MAP size for ease of use and discreetness. Some would accept a larger MAP if it provided longer protection. Most preferred a protection duration of 1 to 3 months or longer; others preferred 1-week protection. Upper arm and thigh were the most preferred application sites. Up to 30 minutes of wear time was considered acceptable; some wanted longer to ensure the drug was fully delivered. Self-administration was valued by all groups; most preferred initial training by a provider.

CONCLUSIONS

Potential users and stakeholders showed strong interest in/acceptance of MAP technology, and their feedback identified key improvements for MAP design. If a MAP containing a high-potency antiretroviral or a MAP containing both an antiretroviral and hormonal contraceptive is developed, these products could improve acceptability/uptake of protection options in sub-Saharan Africa.

Women Want Choices: Opinions from the Share.Learn.Shape Global Internet Survey About Multipurpose Prevention Technology (MPT) Products in Development

Women need multipurpose prevention technologies (MPTs) to simultaneously prevent sexually transmitted infections (STIs), including HIV, with or without contraception. User feedback early in product development is critical for maximizing uptake and continuation. Our global online survey (April 2017-December 2018) explored women's opinions about MPT formulations in development (e.g., fast-dissolving vaginal inserts, vaginal films, intravaginal rings, injectables, implants), preferences for long-acting or "on-demand" methods, and interest in a contraceptive MPT versus products for HIV/STI prevention alone. Of the 630 women in our final analysis (mean 30 years old; range 18-49), 68% were monogamous, 79% completed secondary education, 58% had ≥ 1 child, 56% were from sub-Saharan Africa and 82% preferred a cMPT versus HIV/STI prevention alone. There were no clear preferences for any specific product or product type (long-acting, on-demand, daily). No single product will appeal everyone, however, adding contraception is likely to increase uptake of HIV/STI prevention methods for most women.

Users' Preferred Characteristics of Vaginal Rings for HIV Prevention: A Qualitative Analysis of Two Phase I Trials

Vaginal rings address a critical need for an independently initiated, long-acting HIV prevention method, but their design must be acceptable to promote uptake and adherence. Human-centered design (HCD) may help address design preference questions. In two Phase I studies of vaginal rings for HIV prevention conducted in the United States, we used qualitative interviews to assess participants' perceptions and opinions of the physical characteristics of the ring they used and of a ring's physical characteristics after comparing four ring designs presented via a visual tool. Users were found to prefer ring designs that appear easy to use, are physically comfortable, that function well, and are aesthetically pleasing. The parameters for these features varied widely. Product developers and marketers should consider marketing messages in which the target users feel this product is made to meet their needs and desires. Product developers are encouraged to design using HCD early in ring development (Clinical Trial Registration number: NCT03234400 and NCT03670355).

Women's preferences and acceptance for different drug delivery routes and products

To use or not to use, that is the first decision to take regarding a drug product. This mandatory step for adherence dictates product efficacy. The determinants for such decision do not only rely on the priority of the therapeutic or preventive strategy, but are related to a complex network of perceptions, preferences, personal and cultural backgrounds, and results from previous experiences. Women's preferences for dosage forms and even for drug delivery routes have been mainly studied in the fields of contraception and HIV prevention (and their related multipurpose approaches). Much less attention has been devoted to other therapeutic or preventive strategies. In a time when patient-centred approaches and shared decisions are increasingly valued, considering women's preferences and their main determinants is essential for product development and selection. Such products will be more likely to be chosen and used as intended, increasing efficacy, and reducing the overall costs related with these treatments. This knowledge shall be integrated in early stages of product development. This article reviews the state of the art related with women's preferences and acceptance for different dosage forms and drug delivery routes involved in women's health. The methodologies used for collecting these data and their major drawbacks are discussed. Results obtained from acceptability studies and the main determinants for selection of preventive and treatment drug products are discussed as tools for new developments in the field.

Designing Dual Compartment HIV Prevention Products: Women's Sensory Perceptions and Experiences of Suppositories for Rectal and Vaginal Use

Dual compartment suppositories are being developed to prevent HIV and other sexually transmitted infections. Such products, for use in the rectum, the vagina, or both, could have a significant public health impact by decreasing global incidence of these diseases. In this study, 16 women each used two rheologically distinct suppositories in their vagina and rectum. User Sensory Perception and Experience (USPE) scales assessed sensory experiences during sexual activity to understand whether, and how, women perceive formulation properties in the vagina and rectum. Qualitative data from individual in-depth interviews captured women's descriptions and comparisons of the experiences. Significant differences and large Cohen's d effect sizes between vaginal and rectal experiences of suppository-A were found for three scales: Application (APP): Product Awareness, SEX: Initial Penetration; and SEX: Effortful. Qualitative data provided user experience details that credibly align with these score differences. Near significant differences and large effect sizes were found for two additional scales: SEX: Perceived Wetness with suppository-A and SEX: Messiness with suppository-B. In addition, other scale scores showed medium-to-large effect sizes that correspond to hypothesized sensations associated with biophysical properties of the suppositories. Statistical significance combined with large effect sizes and qualitative data accurately represent the hypothesized perceptibility of suppository properties and identifies performance characteristics relevant to acceptability and adherence; together these data provide discernment of factors that can guide the development of dual compartment products. The Clinical Trial Registration number: NCT02744261.

The new contraceptive revolution: developing innovative products outside of industry†,‡

A significant global unmet need for new contraceptive options for both women and men remains due to side effect profiles, medical concerns, and inconvenience of many currently available products. The pharmaceutical industry has largely abandoned early research and development for contraception and will not likely engage to bring new products to the market unless they have been significantly de-risked by showing promise in early phase clinical trials. This lack of interest by big pharma comes at a time when scientific and technological advances in biology and medicine are creating more opportunities than ever for the development of new and innovative drug products. Novel partnerships between the academic sector, small biotechnology companies, foundations, non-government organizations (NGOs), and the federal government could accelerate the development of new contraceptive products. We discuss the challenges and opportunities that we have encountered as an NGO with a mission to develop novel contraceptive products for low- and middle-income countries and how it differs from developing products for higher-income markets. We hope that our experiences and “lessons learned” will be of value to others as they proceed down the product development path, be it for female or male or for hormonal or nonhormonal contraceptives.

Women-specific routes of administration for drugs: A critical overview

The woman's body presents a number of unique anatomical features that can constitute valuable routes for the administration of drugs, either for local or systemic action. These are associated with genitalia (vaginal, endocervical, intrauterine, intrafallopian and intraovarian routes), changes occurring during pregnancy (extra-amniotic, intra-amniotic and intraplacental routes) and the female breast (breast intraductal route). While the vaginal administration of drug products is common, other routes have limited clinical application and are fairly unknown even for scientists involved in drug delivery science. Understanding the possibilities and limitations of women-specific routes is of key importance for the development of new preventative, diagnostic and therapeutic strategies that will ultimately contribute to the advancement of women's health. This article provides an overview on women-specific routes for the administration of drugs, focusing on aspects such as biological features pertaining to drug delivery, relevance in current clinical practice, available drug dosage forms/delivery systems and administration techniques, as well as recent trends in the field.

The Role of Volume in the Perceptibility of Topical Vaginal Formulations: User Sensory Perceptions and Experiences of Heterosexual Couples During Vaginal Sex

Users' sensory perceptions and experiences (USPEs; perceptibility) of drug formulations can critically impact product adoption and adherence, especially when products rely on appropriate user behaviors (timing of administration, dosing measurement) for effectiveness. The use of topical gel formulations for effective antihuman immunodeficiency virus/sexually transmitted infection (HIV/STI) vaginal microbicides has been associated with messiness and other use-associated challenges, resulting in low adherence. Nonetheless, such formulations remain attractive due to good pharmacokinetics and resulting pharmacodynamics through their volume and surface contact for drug delivery into luminal fluids and mucosa. Consequently, advocates and scientists continue to pursue topical forms [semisolid (e.g., gel, suppository); solid (e.g., film)] to deliver select drugs and offer user choice in HIV/STI prevention. The current data build on previously validated USPE scales evaluating perceptibility of gels with various biophysical/rheological properties. Specifically, increased formulation parameter space adds a new set of properties inherent in quick-dissolving film. We compared film, a product adding no discernable volume to the vaginal environment, to 2 and 3.5 mL hydroxyethyl cellulose gel to consider the impact of volume on user experience. We also examined the USPE scales for evaluation of male sexual partners' experiences. The original USPE scales functioned as expected. Additionally, six new USPE scales were identified in this enhanced parameter space. Significant differences were noted between USPEs in pairwise comparisons, with largest differences between film and high-volume gel. Product developers and behavioral scientists can use these scales to design products, optimizing user experience and maximizing adherence and delivery of efficacious anti-HIV/STI pharmaceuticals. They can be extended to evaluation of additional formulations, devices, and compartments, as well as single- and multipurpose pharmaceuticals. In broader contexts, USPEs could be of value in evaluating formulations and devices to prevent/treat other diseases (e.g., ophthalmologic, dermatologic). Steadfast attention should be given to patient experience, and, where applicable, experiences of partners and/or caregivers.

Development of multipurpose technologies products for pregnancy and STI prevention: update on polyphenylene carboxymethylene MPT gel development†

Current modern contraceptives rely heavily on the use of hormones. These birth control drug products, including pills, patches, injections, and IUDS, have been extremely beneficial to millions of women and their families over the past 50 years. But a surprisingly high number of women abandon such modern methods, many because they cannot tolerate the side effects and others because they have medical issues for which hormonal methods are contraindicated. In addition, modern hormonal methods are simply not available to many women. The extent of this problem is steadily becoming more apparent. We present the case for developing simple nonhormonal vaginal products that women can use when needed, ideal products that are multipurpose and offer both contraception and sexually transmitted disease protection. Gel-based vaginal products are particularly well suited for this purpose. Gels are easy to use, highly acceptable to many women, and can be safely formulated to enhance natural vaginal defenses against infection. However, the development of a new chemical entity for this application faces significant technical and regulatory hurdles. These challenges and our solutions are described for polyphenylene carboxymethylene (PPCM), a novel topical drug in a vaginal gel nearing human clinical trials. We have advanced PPCM from benchtop to IND-enabling studies and provide a brief description of the complex development process. We also describe a simple lab assay which can be used as a biomarker for contraceptive activity to enable pharmacodynamic studies in vaginal contraceptive development, both preclinically and in early human clinical trials.

Towards a roadmap to advance non-hormonal contraceptive multipurpose prevention technologies: strategic insights from key stakeholders†

The development of non-hormonal contraceptives is critical to increase options for women. In combination with prevention against sexually transmitted infections, they can become an important component of multipurpose prevention technologies (MPTs) which address multiple reproductive health needs with a single product. Resulting from multiple rounds of expert consultations, this framework aims to guide the development of non-hormonal contraceptive MPTs. Key informant interviews with experts in family planning and HIV and STI prevention and MPT product developers and funders from around the globe were conducted, reviewed, and coded. Identified key themes were discussed by experts at the November 2019 Eunice Kennedy Shriver National Institute of Child Health and Human Development Contraceptive Development Meeting in Houston, Texas. Seven action strategies were identified to address key research gaps and priorities for advancing the field. They highlight the importance of identifying target populations, a systematic approach to collaborative research, and leveraging knowledge from other fields, including regulatory and patenting, manufacturing, and commercialization expertise. Employing expanded target product profiles and setting go/no-go decisions for non-hormonal MPTs will help to prioritize the most promising candidates in the drug development pipeline. Further, they call for optimizing investments and engagement of stakeholders from public and private sectors. These action strategies aim to facilitate collaboration and innovation amongst multidisciplinary MPT stakeholders. Paramount to success will be enhancing strategic alliances and reconciling the essential social–behavioral context and market forces that drive product use with the complexities of research and development, regulatory approval, and commercialization.

Vaginal multipurpose prevention technologies: promising approaches for enhancing women's sexual and reproductive health

Introduction: Multipurpose prevention technologies (MPTs) have the potential to avert multiple concomitant sexual and reproductive health issues in women such as sexually transmitted infections and unintended pregnancy. MPTs incorporate one or more active pharmaceutical ingredients in a single product, which adds more convenience for users and may promote increased adherence. Various vaginal dosage forms/delivery systems have been studied for designing MPTs. However, several challenges remain that are mainly related to requirements of individual drugs or intended multiple applications.Areas covered: This review focuses on the emerging need and development of vaginal MPTs. It illustrates numerous examples that are currently in the preclinical and clinical development pipeline, highlighting the concept behind vaginal MPTs. The article also highlights the challenges associated with formulation design and development, including regulatory issues that need to be addressed.Expert opinion: Vaginal MPTs present great potential to empower women with novel, efficient, and safe products for protection against sexually transmitted infections and unintended pregnancy. However, several technological issues and regulatory gaps still need to be addressed in order to meet real-world needs.

A Qualitative Systematic Review of Women's Experiences Using Contraceptive Vaginal Rings: Implications for New Technologies

CONTEXT

Vaginal rings are available for contraception and hormone replacement, and are being developed as HIV/STD or multipurpose prevention technologies. A comprehensive understanding of women's expectations of and experiences with rings is urgently needed to inform product development and to optimize ring use.

METHODS

Three databases (PubMed, Global Health and CINAHL) were searched for English-language, peer-reviewed articles published between January 1996 and November 2017 that reported qualitative data on barriers to and facilitators of use of female-controlled contraceptive methods. Data on study methods, findings and conclusions pertaining to contraceptive rings were extracted, organized and analyzed.

RESULTS

Twenty-six articles, all published since 2008, met the inclusion criteria. Seven studies focused largely or entirely on rings (and involved current, former or potential users), while the others focused on other contraceptive methods but included ring-specific data. Familiarity with the ring was low, and women commonly had initial concerns about the method-often related to insertion and removal, cleanliness and discomfort with touching their vagina-that were typically overcome over time. Other major themes were issues related to ring use and discontinuation, the importance of ring-related properties and characteristics, and considerations related to sexual partners and health care providers.

CONCLUSIONS

Qualitative data have the potential to inform ring design and promotion. Future research should further explore women's expectations and experiences with the ring, the value of involving male partners in ring evaluation, and evaluation of interventions to improve patient-provider communication concerning ring choice and use.

A Qualitative Systematic Review of Women's Experiences Using Contraceptive Vaginal Rings: Implications for New Technologies

CONTEXT

Vaginal rings are available for contraception and hormone replacement, and are being developed as HIV/STD or multipurpose prevention technologies. A comprehensive understanding of women's expectations of and experiences with rings is urgently needed to inform product development and to optimize ring use.

METHODS

Three databases (PubMed, Global Health and CINAHL) were searched for English-language, peer-reviewed articles published between January 1996 and November 2017 that reported qualitative data on barriers to and facilitators of use of female-controlled contraceptive methods. Data on study methods, findings and conclusions pertaining to contraceptive rings were extracted, organized and analyzed.

RESULTS

Twenty-six articles, all published since 2008, met the inclusion criteria. Seven studies focused largely or entirely on rings (and involved current, former or potential users), while the others focused on other contraceptive methods but included ring-specific data. Familiarity with the ring was low, and women commonly had initial concerns about the method-often related to insertion and removal, cleanliness and discomfort with touching their vagina-that were typically overcome over time. Other major themes were issues related to ring use and discontinuation, the importance of ring-related properties and characteristics, and considerations related to sexual partners and health care providers.

CONCLUSIONS

Qualitative data have the potential to inform ring design and promotion. Future research should further explore women's expectations and experiences with the ring, the value of involving male partners in ring evaluation, and evaluation of interventions to improve patient-provider communication concerning ring choice and use.

Qualitative exploration of intrinsic and extrinsic factors that influence acceptability of semisoft vaginal suppositories

BACKGROUND

Vaginal microbicides are a promising means to prevent the transmission of HIV and other sexually transmitted infections, by empowering women to initiate use prophylactically when they perceive themselves to be at risk. However, in clinical trials, microbicides have shown mixed results, with the consistent finding that effectiveness varies substantially as a function of user adherence.

METHODS

Based on the assumption that adherence is driven, at least in part, by product properties that influence acceptability, we used softgel technology to develop vaginal drug delivery systems in the intermediate texture space between solids and liquids to overcome potential shortcomings of current dosage forms. Here, we used focus groups and surveys to determine women's initial reactions (i.e., acceptance and willingness-to-try) for semisoft vaginal suppositories intended for HIV and STI prevention, with a specific focus on how perception of and preferences for vaginal suppositories may be influenced by product characteristics such as size, shape, and firmness.

RESULTS

Via focus groups, we identified intrinsic and extrinsic factors relevant to acceptability of semisoft suppository prototypes. Willingness-to-try depended on factors like intended functionality, anticipated leakage, type of sex, recommended frequency of use, type of sexual partner, and perceived risk. When handled ex vivo, shape, size, and firmness of suppositories communicated information about ease of imagined insertion and handling, perceived effectiveness, anticipated awareness and comfort of the product in the body. These impressions were partly based on prior experience with vaginal products.

CONCLUSIONS

Sensory attributes appear to play a substantial role in women's preferences and willingness to try the semisoft suppositories. Using these methods during preclinical development should help efficiently optimize a final product that is both biologically efficacious and preferred by women, toward a goal of enhancing adherence and effectiveness.

Pharmaceutical Approaches to HIV Treatment and Prevention

Human immunodeficiency virus (HIV) infection continues to pose a major infectious disease threat worldwide. It is characterized by the depletion of CD4+ T cells, persistent immune activation, and increased susceptibility to secondary infections. Advances in the development of antiretroviral drugs and combination antiretroviral therapy have resulted in a remarkable reduction in HIV-associated morbidity and mortality. Antiretroviral therapy (ART) leads to effective suppression of HIV replication with partial recovery of host immune system and has successfully transformed HIV infection from a fatal disease to a chronic condition. Additionally, antiretroviral drugs have shown promise for prevention in HIV pre-exposure prophylaxis and treatment as prevention. However, ART is unable to cure HIV. Other limitations include drug-drug interactions, drug resistance, cytotoxic side effects, cost, and adherence. Alternative treatment options are being investigated to overcome these challenges including discovery of new molecules with increased anti-viral activity and development of easily administrable drug formulations. In light of the difficulties associated with current HIV treatment measures, and in the continuing absence of a cure, the prevention of new infections has also arisen as a prominent goal among efforts to curtail the worldwide HIV pandemic. In this review, the authors summarize currently available anti-HIV drugs and their combinations for treatment, new molecules under clinical development and prevention methods, and discuss drug delivery formats as well as associated challenges and alternative approaches for the future.

User input in iterative design for prevention product development: leveraging interdisciplinary methods to optimize effectiveness

The development of HIV-preventive topical vaginal microbicides has been challenged by a lack of sufficient adherence in later stage clinical trials to confidently evaluate effectiveness. This dilemma has highlighted the need to integrate translational research earlier in the drug development process, essentially applying behavioral science to facilitate the advances of basic science with respect to the uptake and use of biomedical prevention technologies. In the last several years, there has been an increasing recognition that the user experience, specifically the sensory experience, as well as the role of meaning-making elicited by those sensations, may play a more substantive role than previously thought. Importantly, the role of the user-their sensory perceptions, their judgements of those experiences, and their willingness to use a product-is critical in product uptake and consistent use post-marketing, ultimately realizing gains in global public health. Specifically, a successful prevention product requires an efficacious drug, an efficient drug delivery system, and an effective user. We present an integrated iterative drug development and user experience evaluation method to illustrate how user-centered formulation design can be iterated from the early stages of preclinical development to leverage the user experience. Integrating the user and their product experiences into the formulation design process may help optimize both the efficiency of drug delivery and the effectiveness of the user.

User evaluations offer promise for pod-intravaginal ring as a drug delivery platform: A mixed methods study of acceptability and use experiences

BACKGROUND

Effective HIV prevention requires efficient delivery of safe and efficacious drugs and optimization of user adherence. The user's experiences with the drug, delivery system, and use parameters are critical to product acceptability and adherence. Prevention product developers have the opportunity to directly control a drug delivery system and its impact on acceptability and adherence, as well as product efficacy. Involvement of potential users during preclinical design and development can facilitate this process. We embedded a mixed methods user evaluation study into a safety and pharmacokinetics (PK) trial of a pod-intravaginal ring delivering antiretroviral agents.

METHODOLOGY

Women enrolled in two cohorts, ultimately evaluating the safety/PK of a pod-IVRs delivering TDF-alone, TDF-FTC, and/or TDF-FTC-MVC. A 7-day use period was targeted for each pod-IVR, regardless of drug or drug combination. During the clinical study, participants provided both quantitative (i.e., survey) and qualitative (i.e., in-depth interview) data capturing acceptability, perceptibility, and adherence behaviors. Initial sexual and reproductive health history surveys, daily diaries, a final acceptability and willingness to use survey, and a qualitative in-depth interview comprised the user evaluation data for each pod-IVR experienced by the participants.

FINDINGS

Overall, the majority of participants (N = 10) reported being willing to use the pod-IVR platform for HIV prevention should it advance to market. Confidence to use the pod-IVR (e.g., insertion, removal) was high. There were no differences noted in the user experience of the pod-IVR platform; that is, whether the ring delivered TDF-alone, TDF-FTC, or TDF-FTC-MVC, users' experiences of the ring were similar and acceptable. Participants did report specific experiences, both sensory and behavioral, that impacted their use behaviors with respect to the ring, and which could ultimately impact acceptability and adherence. These experiences, and user evaluations elicited by them, could both challenge use or be used to leverage use in future trials and product rollout once fully articulated.

CONCLUSIONS

High willingness-to-use data and lack of salient differences in user experiences related to use of the pod-IVR platform (regardless of agents delivered) suggests that the pod-IVR is a feasible and acceptable drug delivery device in and of itself. This finding holds promise both for an anti-HIV pod-IVR and, potentially, a multipurpose prevention pod-IVR that could deliver both prevention for sexually transmitted infections (STIs) including HIV and contraception. Given the very early clinical trial context, further acceptability, perceptibility, and adherence data should continue to be explored, in the context of longer use periods (e.g., 28-day ring use), and in the contexts of sexual activity and menses. Using early design and development contexts to gain insights into potential challenges and facilitators of drug delivery systems such as the pod-IVR could save valuable resources and time as a potential biomedical technology moves through the clinical trial pipeline and into real-world use.

Vaginal film for prevention of HIV: using visual and tactile evaluations among potential users to inform product design

Topical prevention of HIV and other STIs is a global health priority. To provide options for users, developers have worked to design safe, effective and acceptable vaginal dissolving film formulations. We aimed to characterize user experiences of vaginal film size, texture and color, and their role in product-elicited sensory perceptions (i.e. perceptibility), acceptability and willingness to use. In the context of a user-centered product evaluation study, we elicited users' 'first impressions' of various vaginal film formulation designs via visual and tactile prototype inspection during a qualitative user evaluation interview. Twenty-four women evaluated prototypes. Participants considered size and texture to be important for easy insertion. Color was more important following dissolution than prior to insertion. When asked to combine and balance all properties to arrive at an ideal film, previously stated priorities for individual characteristics sometimes shifted, with the salience of some individual characteristics lessening when multiple characteristics were weighted in combination. While first impressions alone may not drive product uptake, users' willingness to initially try a product is likely impacted by such impressions. Developers should consider potential users' experiences and preferences in vaginal film design. This user-focused approach is useful for characterizing user sensory perceptions and experiences relevant to early design of prevention technologies.

A Comparative Pre-Phase I Study of the Impact of Gel Vehicle Volume on Distal Colon Distribution, User Experience, and Acceptability

For persons at risk of HIV infection who practice receptive anal intercourse (RAI), topical rectal microbicides represent a promising option for coitally dependent protection. The study compared colorectal distribution and user sensory experiences of two different volumes of rectal gel for suitability as rectal microbicide. Eight HIV-negative men with a history of recent RAI were enrolled into a two-period, sequence-randomized dosing study comparing 3.5 and 10 ml of radiolabeled (1 mCi ^99mTc-DTPA) universal placebo, hydroxyethyl cellulose gel. Each participant received two doses in the research unit, one of each volume, separated by a washout period of at least 2 weeks. Each research unit dose was followed by a self-administered take-home dose in the context of preparing for RAI. Safety and gastrointestinal distribution were assessed after the research unit doses, safety, perceptibility, and acceptability, were assessed after take-home doses. There were no adverse effects of Grade 2 or higher and all resolved spontaneously. Both volumes were well tolerated and received high acceptability scores. Perceptibility scores showed meaningful effect size differences ranging from Cohen's d = 0.5 to d = 1.2. The 3.5 and 10 ml gel volumes distributed similarly (p > .2) within the rectosigmoid, ranging from 0.69 to 18.84 cm and 1.21 to 19.01 cm from the anorectal junction, respectively. Both volumes covered the typical gastrointestinal distribution of ejaculate following simulated intercourse based on other studies. Either of these gel volumes could reasonably be pursued for the next phase of development of rectal microbicides.