Long-acting injectable cabotegravir: implementation science needed to advance this additional HIV prevention choice

Improving preparedness for introducing and scaling up long-acting HIV pre-exposure prophylaxis in Asia

Long-acting injectable PrEP, particularly cabotegravir (CAB-LA), has the potential to enhance HIV prevention in Asia, and was the topic of a roundtable held in Singapore in June 2023. Despite proven efficacy, CAB-LA's impact in Asia is hindered by regulatory, manufacturing, and cost barriers. There is an urgent need to address these challenges to expedite CAB-LA's introduction and scale-up, including collaborative research, streamlined regulatory processes, and increased manufacturing capacity. We call for better preparedness in long-acting PrEP in research and implementation science, product licensing and accessibility, and capacity readiness for scale-up, to meet the significant demand among key populations in Asia.

Lessons learnt from daily oral PrEP delivery to inform national planning for PrEP ring introduction for women in low-income and middle-income countries: a qualitative inquiry of international stakeholders

INTRODUCTION

Some African countries plan to introduce and scale-up new long-acting pre-exposure prophylaxis methods (LA-PrEP), like the monthly dapivirine vaginal ring (PrEP ring) and injectable cabotegravir. National costed implementation plans, roadmaps for successful product implementation, are often overlooked. International stakeholders engaged in oral PrEP planning, introduction and scale-up are an information resource of lessons learned to advise LA-PrEP planning. We consulted such international stakeholders and synthesised oral PrEP lessons to inform the development of a costed rollout plan template for LA-PrEP.

METHODS

From selected global health organisations (five international nongovernmental, four donor, four university/research and two multilateral), we interviewed 27 representatives based in America, Europe, Asia and Africa about strategic content and approaches for LA-PrEP policy, programming and implementation. We conducted a thematic analysis of the interview data for implementation considerations.

RESULTS

From the consultations, we identified six implementation themes for LA-PrEP introduction and scale-up: (1) ethically increasing choice and avoiding coercion; (2) de-stigmatising PrEP by focusing on preference rather than risk-based eligibility; (3) integrating LA-PrEP into services that are more woman-oriented, couple-oriented and family-oriented, and providing private spaces for LA-PrEP delivery; (4) de-medicalising delivery of relatively safe products (eg, PrEP ring); (5) constructing multilevel, nuanced communication strategies to address measured and perceived product efficacy and effectiveness; and (6) devising product-agnostic, modular approaches to service delivery. Despite the widespread emphasis on integration, few stakeholders offered empirical examples of successful integration approaches and frameworks.

CONCLUSIONS

Lessons learnt from stakeholder participants suggest standardised and modular processes can improve efficiencies in LA-PrEP planning and implementation. Tiered communication strategies addressing product efficacy and effectiveness will improve clients' and providers' efficacy in making informed decisions. Integration is important for LA-PrEP delivery, but data on empirical integration approaches and frameworks is minimal: further research in this discipline is needed.

Global HIV Incidence Analysis and Implications for Affordability Using Long-Acting Cabotegravir Versus Continuous and Event-Driven Oral Preexposure Prophylaxis

BACKGROUND

The HIV Prevention Trials Network (HPTN) 083/084 trials showed up to 88% increased efficacy of long-acting cabotegravir (CAB-LA) versus continuous oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC). However, CAB-LA's high price limits the number of people who can be treated within fixed prevention budgets. Global human immunodeficiency virus (HIV) prevention budgets are highly limited, with TDF/FTC widely available as a low-cost generic. In randomized clinical trials, event-driven TDF/FTC has shown similar preventive efficacy to continuous TDF/FTC.

METHODS

A systematic review of global HIV incidence studies was conducted. Weighted incidence was calculated in each at-risk population. HIV infection rates were evaluated for 5 prevention strategies, with additional HIV testing, education, and service access costs assumed for each ($18 per person per year). Assumed efficacies were 90% (continuous CAB-LA), 60% (continuous TDF/FTC), and 60% (event-driven TDF/FTC). Using weighted incidence and an assumed 100 000 target population, annual HIV infection rates by population were calculated for each prevention strategy.

RESULTS

Ninety-eight studies in 5 230 189 individuals were included. Incidence per 100 person-years ranged from 0.03 (blood donors) to 3.82 (people who inject drugs). Using the number needed to treat to benefit for each strategy, a mean incidence of 2.6 per 100 person-years in at-risk populations, and a 100 000 target population, current-price continuous CAB-LA cost $949 487 per HIV infection successfully prevented, followed by target-price CAB-LA ($11 453), continuous TDF/FTC ($4231), and event-driven TDF/FTC ($1923).

CONCLUSIONS

High prices of CAB-LA limit numbers treatable within fixed budgets. Low-cost event-driven TDF/FTC consistently prevents the most HIV infections within fixed budgets.

The Use of Daily and On-Demand Oral Pre-Exposure Prophylaxis Dosing Strategies Among Young Adult Gay, Bisexual and Other Men who have Sex with Men Enrolled in an mHealth Adherence Intervention

Pre-exposure prophylaxis (PrEP) is a highly effective HIV prevention option for gay, bisexual and other men who have sex with men (GBMSM). However, with newer PrEP options, a greater understanding of whether and why GBMSM switch dosing strategies is needed to inform clinical practice and research. We assessed the dosing strategies (daily or on-demand) of GBMSM enrolled in an mHealth PrEP adherence pilot intervention at four timepoints over approximately 10 months. Among GBMSM with complete data (n = 66), a consistent daily dosing strategy was used by most (73%) participants across all time points, while on-demand PrEP was used at least once during the study period by 27% of participants. A higher percentage of on-demand PrEP users self-reported as Asian/Pacific Islander and had less positive attitudes toward PrEP, adjusting for key sociodemographic variables and intervention arm. Daily PrEP users reported high numbers of sexual partners, and the primary reason that they would switch to on-demand PrEP is reduced sexual activity. At the final assessment, 75% of participants were taking daily PrEP, of whom 27% reported that they would like to switch to another option, including on-demand and long-acting injectable PrEP. While findings were largely descriptive, they showed that switches in PrEP dosing strategies are relatively common and PrEP strategy choice may vary across racial and ethnic groups.

The Future of Pre-Exposure Prophylaxis (PrEP) for HIV Prevention: A Global Qualitative Consultation on Provider Perspectives on New Products and Differentiated Service Delivery

Differentiated service delivery and new products, such as long-acting injectable cabotegravir (CAB-LA) and the dapivirine vaginal ring (DVR), could increase uptake and use of pre-exposure prophylaxis (PrEP) for HIV prevention. We explored PrEP provider perspectives on differentiated PrEP service delivery and new PrEP products to inform World Health Organization (WHO) guidelines and programme implementation. 150 PrEP providers who participated in a WHO survey were randomly selected and 67 were invited for interviews based on geographic representation, provider cadre, gender, experience with community-based PrEP service delivery, and familiarity with new PrEP products. Semi-structured interviews were conducted virtually. Key themes were inductively extracted relating to differentiated service delivery and benefits and concerns regarding new PrEP products. 30 PrEP providers from 24 countries were interviewed. Across regions, providers were supportive of differentiated service delivery to respond to clients' needs and preferences, maintain services during COVID-19, and ensure access for priority populations that may face access challenges. Providers welcomed prospects of offering CAB-LA to their clients but had concerns about HIV testing, costs, and the need for clinic-based services, including staff who can administer injections. Providers felt the DVR was potentially important for some cisgender women, especially young clients and female sex workers, and raised fewer concerns compared to injectable PrEP. Providers' views are critical for the development of guidelines and implementing programmes that will best serve PrEP users. Understanding areas where provider capacities and biases may create barriers can define opportunities for training and support to ensure that providers can deliver effective programmes.

Antimalarial drug discovery: progress and approaches

Recent antimalarial drug discovery has been a race to produce new medicines that overcome emerging drug resistance, whilst considering safety and improving dosing convenience. Discovery efforts have yielded a variety of new molecules, many with novel modes of action, and the most advanced are in late-stage clinical development. These discoveries have led to a deeper understanding of how antimalarial drugs act, the identification of a new generation of drug targets, and multiple structure-based chemistry initiatives. The limited pool of funding means it is vital to prioritize new drug candidates. They should exhibit high potency, a low propensity for resistance, a pharmacokinetic profile that favours infrequent dosing, low cost, preclinical results that demonstrate safety and tolerability in women and infants, and preferably the ability to block Plasmodium transmission to Anopheles mosquito vectors. In this Review, we describe the approaches that have been successful, progress in preclinical and clinical development, and existing challenges. We illustrate how antimalarial drug discovery can serve as a model for drug discovery in diseases of poverty.

Pre-exposure prophylaxis service among men who have sex with men in Malaysia: findings from a discrete choice experiment

Men who have sex with men (MSM) in Malaysia are disproportionately affected by HIV. As pre-exposure prophylaxis (PrEP) is being introduced, we assessed population-based PrEP delivery preferences among MSM in Malaysia. We conducted a discrete choice experiment through an online survey among 718 MSM. The survey included 14 choice tasks presenting experimentally varied combinations of five attributes related to PrEP delivery (i.e., cost, dosing strategy, clinician interaction strategy, dispensing venue, and burden of visits to start PrEP). We used latent class analysis and Hierarchical Bayesian modeling to generate the relative importance of each attribute and preference across six possible PrEP delivery programs. PrEP dosing, followed by cost, was the most important attribute. The participants were clustered into five preference groups. Two groups (n = 290) most commonly preferred on-demand, while the other three preferred injectable PrEP. One group (n = 188) almost exclusively considered cost in their decision-making, and the smallest group (n = 86) was substantially less interested in PrEP for reasons unrelated to access. In simulated scenarios, PrEP initiation rates varied by the type of program available to 55·0% of MSM. Successful PrEP uptake among Malaysian MSM requires expanding beyond daily oral PrEP to on-demand and long-acting injectable PrEP, especially at affordable cost.

Shaping and coordinating the implementation science agenda for injectable cabotegravir for PrEP: the role of the Biomedical Prevention Implementation Collaborative (BioPIC)

INTRODUCTION

Data from two randomized controlled trials (RCTs) showed that injectable cabotegravir (CAB) for pre-exposure prophylaxis (PrEP) was efficacious in reducing HIV acquisition. The US Food and Drug Administration approved CAB for PrEP in December 2021; Australia in August 2022; Zimbabwe in October 2022; South Africa in November 2022; Malawi in March 2023; and regulatory approvals are being sought in additional countries. The World Health Organization (WHO) recommended CAB be offered to people at substantial risk of HIV in July 2022. However, implementation experience beyond RCTs is limited. As countries consider CAB implementation, questions remain regarding delivery and involvement of populations excluded from the trials. A coordinated approach is needed to ensure these are addressed and CAB can be introduced in low- and middle-income countries in timely, acceptable and effective ways.

DISCUSSION

Beginning in 2018, the Biomedical Prevention Implementation Collaborative (BioPIC) convened over 100 global health experts to develop a comprehensive introduction strategy for CAB. Using this roadmap, country landscaping for CAB introduction and lessons from oral PrEP implementation, AVAC and WHO co-convened 50 researchers, donors, implementers and civil society in September 2021 to: (1) identify questions and evidence gaps related to CAB across contexts and partners; (2) define the implementation science agenda; and (3) agree on mechanism(s) for future coordination. As a result, CAB-related questions were identified, including: defining optimal and feasible HIV testing strategies that expand access; delivery models; integration with a range of services, including family planning and antenatal care; and embedding CAB in demand generation for HIV prevention choices. Through convenings and mapping of implementation research, BioPIC identified gaps in populations, geographies and delivery approaches.

CONCLUSIONS

The introduction strategy refined by BioPIC lays the groundwork for future HIV prevention products. Ongoing policy and implementation dialogue is critical to accelerate the design of CAB implementation studies that adequately address priority knowledge gaps. Additional long-acting HIV prevention products may be available over the next 5 years, increasing choice, but potentially making delivery and stakeholder engagement more complex. Ongoing coordination with WHO will accelerate the adoption of evidence-based policies and wide-scale implementation, and lessons from BioPIC can inform introduction processes for long-acting HIV prevention products.

High Interest in Long-acting Injectable Pre-exposure Prophylaxis (LAI-PrEP) for HIV Prevention Among Men Who Have Sex With Men (MSM): Result From A Nationwide Survey in Malaysia

The recent approval of long-acting injectable cabotegravir (CAB-LA) as PrEP for HIV prevention could be an attractive alternative for MSM, particularly among those who face barriers to adherence using the oral pill. This study reports on the awareness of long-acting injectable PrEP (LAI-PrEP) and factors associated with interest in LAI-PrEP use among a nationwide sample of MSM in Malaysia. An online cross-sectional survey was conducted between August and September 2021 to explore perspectives on PrEP modalities among Malaysian MSM (N = 870). Convenience sampling was used to recruit participants using ads on two platforms hornet and facebook. While only 9.1% of the study participants were aware of LAI-PrEP, the majority had heard of oral PrEP (80.9%). After giving a description of it, a large majority (86.6%) expressed interest in using it if made accessible. Those who had a prior history of HIV testing (aOR = 1.9; 95% CI = 1.2-3.2) were more likely to use LAI-PrEP. Interestingly, despite the concerns related to potential high cost (aOR = 3.4; 95% CI = 2.1-5.5) and long-term side effects (aOR = 1.9; 95% CI = 1.2-3.1), the majority of the participants were interested in using LAI-PrEP. Those who were afraid of (or disliked) syringes were less interested in using it (aOR = 0.2; 95% CI; 0.1-0.4). In the recent context that LAI-PrEP was shown to be safe and effective at preventing HIV, our results indicate its potential relevance as an additional PrEP option that could accelerate the uptake and scale-up of PrEP. However, it is crucial to conduct future research urgently to improve the understanding of strategies that could enhance the accessibility, acceptability, and affordability of LAI-PrEP for MSM in low- and middle-income countries, including Malaysia.

Strengthening implementation guidelines for HIV service delivery: Considerations for future evidence generation and synthesis

Ingrid Eshun-Wilson and colleagues summarize gaps in primary HIV implementation research methods and reporting, and propose areas for future methodological development.