Phase 1 pharmacokinetics and safety study of extended duration dapivirine vaginal rings in the United States

Phase 1 randomized trials to assess safety, pharmacokinetics, and vaginal bleeding associated with use of extended duration dapivirine and levonorgestrel vaginal rings

BACKGROUND

Vaginal rings formulated to deliver two drugs simultaneously have potential as user-controlled, long-acting methods for dual prevention of HIV and pregnancy.

METHODS

Two phase 1 randomized trials (MTN-030/IPM 041 and MTN-044/IPM 053/CCN019) respectively enrolled 24 and 25 healthy, HIV-negative participants to evaluate safety, pharmacokinetics, and vaginal bleeding associated with use of a vaginal ring containing 200mg dapivirine (DPV) and 320mg levonorgestrel (LNG) designed for 90-day use. MTN-030/IPM 041 compared the DPV/LNG ring to a DPV-only ring (200mg) over 14 days of use. MTN-044/IPM 053/CCN019 compared continuous or cyclic use of the DPV/LNG ring over 90 days of use. Safety was assessed by recording adverse events (AEs). DPV and LNG concentrations were quantified in plasma, cervicovaginal fluid, and cervical tissue. Vaginal bleeding was self-reported.

RESULTS

There were no differences in the proportion of participants with grade ≥2 genitourinary AEs or grade ≥3 AEs with DPV/LNG ring vs. DPV ring use (p = .22), or with DPV/LNG ring continuous vs. cyclic use (p = .67). Higher plasma DPV concentrations were observed in users of DPV/LNG compared to DPV-only rings (Cmax p = 0.049; AUC p = 0.091). Plasma DPV and LNG concentrations were comparable with continuous and cyclic use (Cmax p = 0.74; AUC p = 0.25). With cyclic use, median nadir plasma DPV concentration was approximately 300 pg/mL two days after removal and median t1/2 for cervicovaginal fluid DPV concentration was 5.76 hours (n = 3). Overall bleeding experiences did not differ between continuous and cyclic users (p = 0.12).

CONCLUSIONS

The extended duration DPV/ LNG rings were well tolerated and the observed DPV concentrations in plasma and cervicovaginal fluid when used continuously exceeded concentrations observed in previous DPV ring efficacy studies. LNG concentrations in plasma were comparable with other efficacious LNG-based contraceptives. Genital DPV concentrations had a short half-life and were thus not well sustained following ring removal.

Development and verification of mechanistic vaginal absorption and metabolism model to predict systemic exposure after vaginal ring and gel application

AIMS

The current work describes the development of mechanistic vaginal absorption and metabolism model within Simcyp Simulator to predict systemic concentrations following vaginal application of ring and gel formulations.

METHODS

Vaginal and cervix physiology parameters were incorporated in the model development. The study highlights the model assumptions including simulation results comparing systemic concentrations of 5 different compounds, namely, dapivirine, tenofovir, lidocaine, ethinylestradiol and etonogestrel, administered as vaginal ring or gel. Due to lack of data, the vaginal absorption parameters were calculated based on assumptions or optimized. The model uses release rate/in vitro release profiles with formulation characteristics to predict drug mass transfer across vaginal tissue into the systemic circulation.

RESULTS

For lidocaine and tenofovir vaginal gel, the predicted to observed AUC0-t and Cmax ratios were well within 2-fold error limits. The average fold error (AFE) and absolute AFE indicating bias and precision of predictions range from 0.62 to 1.61. For dapivirine, the pharmacokinetic parameters are under and overpredicted in some studies due to lack of formulation composition details and relevance of release rate used in ring model. The predicted to observed AUC0-t and Cmax ratios were well within 2-fold error limits for etonogestrel and ethinylestradiol vaginal ring (AFEs and absolute AFEs from 0.84 to 1.83).

CONCLUSION

The current study provides first of its kind physiologically based pharmacokinetic framework integrating physiology, population and formulation data to carry out in silico mechanistic vaginal absorption studies, with the potential for virtual bioequivalence assessment in the future.

Two into one does go: Formulation development of a multipurpose combination vaginal ring releasing dapivirine and metronidazole for prevention of HIV infection and treatment of bacterial vaginosis

Bacterial vaginosis (BV) is a common but often asymptomatic dysbiosis of the human vagina characterized by an imbalance in the normal vaginal microbiota due to loss of lactobacilli and an overgrowth of certain anaerobic bacteria. While BV itself is not a sexually transmitted infection, it is associated with an increased risk in women of various sexually acquired infections, including human immunodeficiency virus (HIV) infection. There is, therefore, a strong rationale for pursuing new multipurpose products that seek to treat or prevent BV alongside preventing HIV infection. With the dapivirine-releasing vaginal ring for HIV prevention now approved in several African countries, here we report formulation development of a next-generation ring product that releases both dapivirine (DPV) and the antibiotic drug metronidazole (MET). Following thermal analysis studies to characterize the phase behaviour of DPV-MET mixtures and rheological analysis to assess the cure characteristics of the active silicone elastomer mixes, matrix-type rings were manufactured containing 25 or 200 mg DPV in combination with 100, 250, 500, 1000 or 2000 mg MET. The results for drug content, in vitro release, mechanical testing, and Gardnerella vaginalis time-kill experiments demonstrate the feasibility of incorporating both DPV and MET in a matrix-type ring formulation and indicate that clinically effective release rates may be possible.

HIV Pre-Exposure Prophylaxis: New and Upcoming Drugs to Address the HIV Epidemic

Human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) provides a critical intervention toward ending the HIV epidemic and protecting people with reasons to utilize PrEP. PrEP options continue to expand as new administration modalities offer the potential to tailor PrEP use for individual success. We have provided the evidence for new and emerging antiretroviral agents for PrEP (cabotegravir, lenacapavir, dapivirine, and broadly neutralizing antibodies), divided into pharmacology, animal model, and human data, accompanied by a summary and suggested place in therapy. Cabotegravir is a US Food and Drug Administration (FDA)-approved intramuscular injection given every 2 months with a strong body of evidence demonstrating efficacy for HIV PrEP, lenacapavir administered subcutaneously every 6 months is currently under investigation for HIV PrEP, dapivirine vaginal ring is an available PrEP option for women in certain areas of Africa, and broadly neutralizing monoclonal antibodies have been challenged in demonstrating efficacy in phase 1-2 study for HIV PrEP to date. Clinical literature for individual agents is discussed with data from major studies summarized in tables. This review provides a detailed overview of recently available and premier candidate PrEP drugs.

Advances in long-acting slow effective release antiretroviral therapies for treatment and prevention of HIV infection

Adherence to daily oral antiretroviral therapy (ART) is a barrier to both treatment and prevention of human immunodeficiency virus (HIV) infection. To overcome limitations of life-long daily regimen adherence, long-acting (LA) injectable antiretroviral (ARV) drugs, nanoformulations, implants, vaginal rings, microarray patches, and ultra-long-acting (ULA) prodrugs are now available or in development. These medicines enable persons who are or at risk for HIV infection to be treated with simplified ART regimens. First-generation LA cabotegravir, rilpivirine, and lenacapavir injectables and a dapivirine vaginal ring are now in use. However, each remains limited by existing dosing intervals, ease of administration, or difficulties in finding drug partners. ULA ART regimens provide an answer, but to date, such next-generation formulations remain in development. Establishing the niche will require affirmation of extended dosing, improved access, reduced injection volumes, improved pharmacokinetic profiles, selections of combination treatments, and synchronization of healthcare support. Based on such needs, this review highlights recent pharmacological advances and a future treatment perspective. While first-generation LA ARTs are available for HIV care, they remain far from ideal in meeting patient needs. ULA medicines, now in advanced preclinical development, may close gaps toward broader usage and treatment options.

Participant experiences with a multipurpose vaginal ring for HIV and pregnancy prevention during a phase 1 clinical trial: learning from users to improve acceptability

Introduction

With high concurrent global rates of HIV incidence and unintended pregnancy, there is a need to provide options beyond condoms to enable users to simultaneously prevent HIV acquisition and pregnancy. Multiple vaginal rings are in development as "MPTs" (multipurpose prevention technologies) as they are shown to provide several co-occurring benefits such as discretion, convenience, reversibility and user control.

Methods

In this Phase 1 trial of a 3-month MPT ring in the U.S., 25 participants (low-risk for HIV and pregnancy) were randomized to use the study ring for 90 days continuously or in 28-day cycles with 2-day removal periods in between. All participants completed in-depth interviews at the end of their study participation.

Results

Overall, the ring was well tolerated. Participants resoundingly endorsed the concept of an extended-use, dual-purpose vaginal ring, but reported too many functional challenges and side effects to endorse this particular ring. Participants assigned to the continuous regimen reported more positive experiences with ring use than those in the cyclic group. A minority of participants who experienced minimal side effects and did not experience challenges with vaginal retention of the ring found it appealing. However, the majority of participants experienced challenges (ring slippage, expulsions, side effects, vaginal bleeding changes) with product use that outweighed the potential benefits and led them to report that - in the future - they would not be interested in using this specific version of the ring in its current form. A subset expressed interest in using the current MPT ring under certain conditions (e.g., if fewer expulsions, less bleeding, higher risk for HIV/pregnancy).

Discussion

User feedback regarding participant experiences and challenges with the study ring was continuously shared with the product developer, underscoring the value of early-stage end-user feedback in product development.

The future of HIV pre-exposure prophylaxis adherence: reducing barriers and increasing opportunities

The effectiveness of HIV pre-exposure prophylaxis (PrEP) hinges on adherence, which has been restricted by multifaceted barriers. Uptake of PrEP has been impeded by poor access resulting from high costs, provider uncertainty, discrimination, stigma, and poor understanding within the health-care community and the public of who can benefit from PrEP. Other important barriers to adherence and persistence over time relate to individuals (eg, depression) and their community, partners, and family (eg, poor support), and their effects vary substantially with each person, population, and setting. Despite these challenges, key opportunities for improving PrEP adherence exist, including novel delivery systems, tailored individual interventions, mobile health and digital health interventions, and long-acting formulations. Objective monitoring strategies will help to improve adherence interventions and alignment of PrEP use with the need for HIV prevention (ie, prevention-effective adherence). The future of PrEP adherence lies in person-centred approaches to service delivery that meet the needs of individuals while creating supportive environments and facilitating health-care access and delivery.

Acceptability and Preference for 3-Month Versus 1-Month Vaginal Rings for HIV-1 Risk Reduction Among Participants in a Phase 1 Trial

Background: The monthly dapivirine vaginal ring provides partial protection against HIV, and a longer duration ring may reduce user burden and improve adherence. We examined acceptability and preference for 3-month versus 1-month rings for HIV-1 risk reduction in a phase 1 clinical trial. Materials and Methods: In Microbicide Trials Network-036/International Partnership for Microbicides 047, 49 HIV-negative participants aged 18-45 were randomized to one of two 3-month rings or the 1-month ring. Acceptability ratings were collected at enrollment, week 4, and study exit (week 13). At exit, ring preference was assessed quantitatively among all participants and a randomly selected subset of 24 participants completed in-depth interviews. Quantitative and qualitative findings were integrated to explore factors influencing acceptability and preference. Results: Acceptability of each ring was initially moderate and increased during the trial. Ratings were lower in the 3-month ring arms than the 1-month arm at each time point, including baseline. Most participants (34/47; 72%) preferred a 3-month ring at exit; however, this proportion was significantly lower within some subgroups characterized by site, education, race/ethnicity, and experiences with ring use. Qualitative interviews revealed reservations about hygiene and safety of the 3-month ring, including discomfort with use during menses, but these were usually outweighed by its increased convenience. Conclusions: Both ring durations were highly acceptable at study exit. Although most participants preferred a 3-month ring, preference was more divided in certain subgroups, highlighting the benefit of offering different duration options. Providing additional support to address concerns about hygiene and safety may improve acceptability of a 3-month vaginal ring.

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).

Promise, perils and cautious optimism: the next frontier in long-acting modalities for the treatment and prevention of HIV

PURPOSE OF REVIEW

This paper provides a critical review of recent therapeutic advances in long-acting (LA) modalities for human immunodeficiency virus (HIV) treatment and prevention.

RECENT FINDINGS

LA injectable antiretroviral therapy (ART) has been approved in the United States, Canada and Europe; the United States also has approved LA injectable preexposure prophylaxis (PrEP) and the World Health Organization has recommended the vaginal PrEP ring. Current LA PrEP modalities in clinical trials include injections, films, rings, and implants; LA ART modalities in trials include subcutaneous injections and long-term oral pills. Although LA modalities hold incredible promise, global availability is inhibited by long-standing multilevel perils including declining multilateral funding, patent protections and lack of political will. Once available, access and uptake are limited by factors such as insurance coverage, clinic access, labor markets, stigma, and structural racism and sexism. These must be addressed to facilitate equitable access for all.

SUMMARY

There have been tremendous recent advances in the efficacy of LA ART and PrEP modalities, providing renewed hope that 'ending the HIV epidemic' is within reach. However, pervasive socio-structural inequities limit the promise of LA modalities, highlighting the need for cautious optimism in light of the embedded inequities in the trajectory of research, development, and population-level implementation.

Vaginal ring acceptability: A systematic review and meta-analysis of vaginal ring experiences from around the world

OBJECTIVE

The vaginal ring (ring) is a female-initiated, long-acting drug delivery system for different indications, including HIV prevention. Our aim was to provide evidence for acceptability of the vaginal ring across indications to support dapivirine and multipurpose prevention technology ring introduction and roll out.

STUDY DESIGN

This systematic review and meta-analysis followed PRISMA guidelines. We searched PubMed, Web of Science, Embase, and grey literature for publications reporting favorable ring acceptability and secondary outcomes involving actual ring use (comfort, ease of ring use, ring comfort during sex, expulsions, and vaginal symptoms) or hypothetical acceptability for any indication published January 1, 1970-June 15, 2021. We estimated random-effects pooled prevalence, assessing between-study variation using meta-regression.

RESULTS

Of 2,234 records, we included 123 studies with 40,434 actual and hypothetical ring users. The primary outcome assessment included 50 studies with 60 ring subgroups totaling 19,271 ring users. The favorable acceptability pooled prevalence was 85.6% (95%CI 81.3, 89.0), while hypothetical acceptability among non-ring users was 27.6% (95%CI 17.5, 40.5). In meta-regression, acceptability was higher in menopause (95.4%; 95%CI 88.4, 98.2) compared to contraceptive rings (83.7%; 95%CI 75.6, 89.5). Acceptability was lower in pharmacokinetic studies (50%; 95%CI 22.1, 77.9) compared to RCTs (89.5%; 95%CI 85.8.92.4) and in studies assessing acceptability at ≥12 months (78.5%; 95%CI 66.5, 87.1) versus studies assessing acceptability at <3 months (91.9%; 95%CI 83.7, 96.1). European (90.6%; 95%CI 83.9, 94.7), Asian (97.1%; 95%CI 92.0, 99.0), and multi-region studies (93.5%; 95%CI 84.6, 97.4) reported more favorable acceptability compared to African studies (59.4%; 95%CI 38.3, 77.5). Secondary outcomes were similarly favorable, including ring comfort (92.9%; 95%CI 89.2, 95.4), ease of use (90.9%; 95%CI 86.5, 94.0), and comfort during sex (82.7%; 95%CI 76.4, 87.6). Limitations include inconsistent outcome definitions and unmeasured factors affecting acceptability.

CONCLUSIONS

Women who used vaginal rings reported they were acceptable across indications geographic regions and indications. Policy makers should consider the ring as an important option for pregnancy and HIV prevention drug development.

IMPLICATIONS

This review found favorable acceptability among vaginal ring users across indications and geographic areas, in contrast to low hypothetical acceptability among non-users. Vaginal rings are an important drug delivery system for pregnancy and HIV preventions, and scale-up should plan to address initial hesitancy among new users.

HIV prevention: better choice for better coverage

Introduction

Antiretroviral‐based pre‐exposure prophylaxis (PrEP) is today an established, effective and safe method of HIV prevention used in multiple countries worldwide by a broad range of populations at risk of HIV infection. Biomedical innovations are critical in supporting the primary prevention of HIV; however, their potential can only be maximized if end‐user challenges are recognized, described and used to develop next‐generation models.

Discussion

First‐generation PrEP, a daily oral pill, is highly efficacious, discreet and affords users the ability to commence and conclude treatment rapidly. However, consistent daily adherence and persistence is challenging, especially among younger populations, due in part to side effects, the risk of stock‐outs and a lack of pill storage options. Second‐generation PrEP, longer acting agents that require less frequent dosing, could overcome such challenges. Agents that have shown efficacy in clinical trials include a monthly vaginal ring and PrEP injectables to be administered every 8 weeks, while products in development include 6 monthly injectables, oral therapy that uses monthly rather than daily pills, implants and the potential for long‐acting passive immunization.

Conclusions

Second‐generation PrEP agents will have the potential to offer improved adherence and less frequent reminders once they have undergone further development and the delivery systems that will best support them have been established. In order to pursue global UNAIDS targets of reducing new HIV infections to fewer than 500,000 annually by 2025, and to ensure that all people have access to prevention options that meet their specific prevention needs, both early and next‐generation PrEP options are needed.

Dapivirine Vaginal Ring for HIV Prevention in Women in South Africa

Young women remain disproportionately affected by the HIV epidemic in South Africa. Clinical trials have shown that the dapivirine vaginal ring (DVR) is safe and effective at reducing HIV infection in women. In March 2022, the South African Health Products Regulatory Authority approved the use of the DVR in women aged 18 years and older who are unable or unwilling to use oral pre-exposure prophylaxis, as an additional choice for preventing HIV in women at substantial risk. Modelling studies have suggested that the DVR could have a substantial impact if prioritized for women at substantial risk of HIV or women aged 22–29 years. The licensing of the DVR in South Africa is a milestone event that brings the first long-acting and woman-controlled HIV prevention method another step closer to reaching the people who need it. As South Africa prepares its introduction, it is critical to examine the unmet need for HIV prevention and to review the clinical trial data that led to the DVR's approval.

Manufacturing and Examination of Vaginal Drug Delivery System by FDM 3D Printing

Vaginal drug delivery systems can provide a long-term and constant liberation of the active pharmaceutical ingredient even for months. For our experiment, FDM 3D printing was used to manufacture the vaginal ring samples from thermoplastic polyurethane filament, which enables fast manufacturing of complex, personalized medications. 3D printing can be an excellent alternative instead of industrial manufacturing, which is complicated and time-consuming. In our work, the 3D printed vaginal rings were filled manually with jellified metronidazole or chloramphenicol for the treatment of bacterial vaginosis. The need for manual filling was certified by the thermogravimetric and heatflow assay results. The manufactured samples were analyzed by an Erweka USP type II Dissolution Apparatus, and the dissolution profile can be distinguished based on the applied jellifying agents and the API's. All samples were considered non-similar based on the pairwise comparison. The biocompatibility properties were determined by prolonged MTT assay on HeLa cells, and the polymer could be considered non-toxic. Based on the microbiological assay on E. coli metronidazole and chitosan containing samples had bactericidal effects while just metronidazole or just chitosan containing samples bacteriostatic effect. None of these samples showed a fungistatic or fungicide effect against C. albicans. Based on our results, we successfully manufactured 3D printed vaginal rings filled with jellified metronidazole.

Phase 1 pharmacokinetics and safety study of extended duration dapivirine vaginal rings in the United States

INTRODUCTION

Vaginal rings are a promising approach to provide a woman-centred, long-acting HIV prevention strategy. Prior trials of a 25 mg dapivirine (DPV) ring have shown a favourable safety profile and approximately 30% risk reduction of HIV-1 infection. Extended duration rings replaced every three months may encourage user adherence, improve health service efficiency and reduce cost overall. We evaluated safety, pharmacokinetics, adherence and acceptability of two three-month rings with different DPV dosages, compared with the monthly DPV ring.

METHODS

From December 2017 to October 2018, MTN-036/IPM-047 enrolled 49 HIV-negative participant in Birmingham, Alabama and San Francisco, California into a phase 1, randomized trial comparing two extended duration (three-month) rings (100 or 200 mg DPV) to a monthly 25 mg DPV ring, each used over 13 weeks, with follow-up completed in January 2019. Safety was assessed by recording adverse events (AEs). DPV concentrations were quantified in plasma, cervicovaginal fluid (CVF) and cervical tissue, at nominal timepoints. Geometric mean ratios (GMRs) relative to the comparator ring were estimated from a regression model.

RESULTS

There were no differences in the proportion of participants with grade ≥2 genitourinary AEs or grade ≥3 AEs in the extended duration versus monthly ring arms (p = 1.0). Plasma and CVF DPV concentrations were higher in the extended duration rings compared to the monthly ring. Plasma GMRs were 1.31 to 1.85 and 1.41 to 1.86 and CVF GMRs were 1.45 to 2.87 and 1.74 to 2.60 for the 100 and 200 mg ring respectively. Cervical tissue concentrations were consistently higher in the 200 mg ring (GMRs 2.36 to 3.97). The majority of participants (82%) were fully adherent (ring inserted at all times, with no product discontinuations/outages) with no differences between the monthly versus three-month rings. Most participants found the ring acceptable (median = 8 on 10-point Likert scale), with a greater proportion of participants reporting high acceptability (9 or 10) in the 25 mg arm (73%) compared with the 100 mg (25%) and 200 mg (44%) arms (p = 0.01 and p = 0.15 respectively).

CONCLUSIONS

The extended duration DPV rings were well-tolerated and achieved higher DPV concentrations compared with the monthly DPV ring. These findings support further evaluation of three-month DPV rings for HIV prevention.