The Promise of Improved Adherence With Long-Acting Antiretroviral Therapy: What Are the Data?

Small Molecule Drugs Targeting Viral Polymerases

Small molecules that specifically target viral polymerases-crucial enzymes governing viral genome transcription and replication-play a pivotal role in combating viral infections. Presently, approved polymerase inhibitors cover nine human viruses, spanning both DNA and RNA viruses. This review provides a comprehensive analysis of these licensed drugs, encompassing nucleoside/nucleotide inhibitors (NIs), non-nucleoside inhibitors (NNIs), and mutagenic agents. For each compound, we describe the specific targeted virus and related polymerase enzyme, the mechanism of action, and the relevant bioactivity data. This wealth of information serves as a valuable resource for researchers actively engaged in antiviral drug discovery efforts, offering a complete overview of established strategies as well as insights for shaping the development of next-generation antiviral therapeutics.

Acceptability of Long-Acting Injectable Antiretroviral Therapy Among People with HIV Receiving Care at Three Ryan White Funded Clinics in the United States

Understanding the acceptability of long-acting injectable antiretroviral therapy (LAI-ART) among people with HIV (PWH), especially priority populations, is essential for effective implementation. We conducted semi-structured interviews with patients in three Ryan White-funded HIV clinics in San Francisco, Chicago, and Atlanta. We employed maximal variation sampling across age, gender, race, ethnicity, and time living with HIV and oversampled for individuals with suboptimal clinical engagement. An 8-step hybrid deductive and inductive thematic analysis approach guided data analysis. Between August 2020 and July 2021, we conducted 72 interviews. Median age was 46 years; 28% were ciswomen, 7% transwomen, 44% Black/African-American and 35% Latinx, 43% endorsed a psychiatric diagnosis, 35% were experiencing homelessness/unstable housing, and 10% had recent substance use. Approximately 24% were sub-optimally engaged in care. We observed a spectrum of LAI-ART acceptability, ranging from enthusiasm to hesitancy to rejection. We also characterized four emergent orientations towards LAI-ART: innovator, pragmatist, deliberator, and skeptic. Overall, the majority of participants expressed favorable initial reactions towards LAI-ART. Most approached LAI-ART pragmatically, but acceptability was not static, often increasing over the course of the interview. Participants considered their HIV providers as essential for affirming personal relevance. HIV stigma, privacy concerns, and medical mistrust had varied impacts, sometimes facilitating and other times hindering personal relevance. These findings held across priority populations, specifically young adults, cis/trans women, racial/ethnic minorities, and individuals with suboptimal clinical engagement. Further research is needed to explore the transition from hypothetical acceptance to uptake and to confirm the actual benefits and drawbacks of this treatment.

Lenacapavir: A Novel, Potent, and Selective First-in-Class Inhibitor of HIV-1 Capsid Function Exhibits Optimal Pharmacokinetic Properties for a Long-Acting Injectable Antiretroviral Agent

Lenacapavir (LEN) is a picomolar first-in-class capsid inhibitor of human immunodeficiency virus type 1 (HIV-1) with a multistage mechanism of action and no known cross resistance to other existing antiretroviral (ARV) drug classes. LEN exhibits a low aqueous solubility and exceptionally low systemic clearance following intravenous (IV) administration in nonclinical species and humans. LEN formulated in an aqueous suspension or a PEG/water solution formulation showed sustained plasma exposure levels with no unintended rapid drug release following subcutaneous (SC) administration to rats and dogs. A high total fraction dose release was observed with both formulations. The long-acting pharmacokinetics (PK) were recapitulated in humans following SC administration of both formulations. The SC PK profiles displayed two-phase absorption kinetics in both animals and humans with an initial fast-release absorption phase, followed by a slow-release absorption phase. Noncompartmental and compartmental analyses informed the LEN systemic input rate from the SC depot and exit rate from the body. Modeling-enabled deconvolution of the input rates from two processes: absorption of the soluble fraction (minor) from a direct fast-release process leading to the early PK phase and absorption of the precipitated fraction (major) from an indirect slow-release process leading to the later PK phase. LEN SC PK showed flip-flop kinetics due to the input rate being substantially slower than the systemic exit rate. LEN input rates via the slow-release process in humans were slower than those in both rats and dogs. Overall, the combination of high potency, exceptional stability, and optimal release rate from the injection depot make LEN well suited for a parenteral long-acting formulation that can be administered once up to every 6 months in humans for the prevention and treatment of HIV-1.

Physiologically Based Pharmacokinetic Modelling of Cabotegravir Microarray Patches in Rats and Humans

Microarray patches (MAPs) are currently under investigation as a self-administered, pain-free alternative used to achieve long-acting (LA) drug delivery. Cabotegravir is a potent antiretroviral that has demonstrated superior results over current pre-exposure prophylaxis (PrEP) regimens. This study aimed to apply physiologically based pharmacokinetic (PBPK) modelling to describe the pharmacokinetics of the dissolving bilayer MAP platform and predict the optimal dosing strategies for a once-weekly cabotegravir MAP. A mathematical description of a MAP was implemented into a PBPK model, and empirical models were utilised for parameter estimation. The intradermal PBPK model was verified against previously published in vivo rat data for intramuscular (IM) and MAP administration, and in vivo human data for the IM administration of LA cabotegravir. The verified model was utilised for the prediction of 300 mg, 150 mg and 75 mg once-weekly MAP administration in humans. Cabotegravir plasma concentrations >4 × protein-adjusted 90% inhibitory concentration (PA-IC90) (0.664 µg/mL) and >8 × PA-IC90 (1.33 µg/mL) were set as targets. The 75 mg, 150 mg and 300 mg once-weekly cabotegravir MAP regimens were predicted to sustain plasma concentrations >4 × PA-IC90, while the 300 mg and 150 mg regimens achieved plasma concentrations >8 × PA-IC90. These data demonstrate the potential for a once-weekly cabotegravir MAP using practical patch sizes for humans and inform the further development of cabotegravir MAPs for HIV PrEP.

Preferences of Patients and Providers in High-Burden Malaria Settings for Long-Acting Malaria Chemoprevention

Antimalarial medications are recommended for chemoprevention as part of malaria control programs to decrease the morbidity and mortality related to more than 200 million infections each year. We sought to evaluate patient and provider acceptability of malaria chemoprevention in a long-acting formulation. We administered questionnaires to patients and providers in malaria endemic districts in Kenya and Zambia. Questions explored preferences and concerns around long-acting antimalarial formulations compared with oral formulations. We recruited 202 patient respondents (Kenya, n = 102; Zambia, n = 100) and 215 provider respondents (Kenya, n = 105; Zambia, n = 110). Long-acting injection was preferred to oral pills, whereas oral pills were preferred to implant or transdermal administration by patient respondents. Of 202 patient respondents, 80% indicated that they 'definitely would try' malaria chemoprevention offered by injection instead of oral pills. Of parents or guardians, 84% of 113 responded that they 'definitely would' have their child age < 12 years and 90% of 88 'definitely would' have their child ≥12 years receive an injection for malaria prevention. Provider respondents indicated that they would be more likely to prescribe a long-acting injectable product compared with an oral product for malaria chemoprevention in adults (70%), adolescents ages 12 years and older (67%), and children <12 years (81%). Potential for prolonged adverse effects with long-acting products was the highest concern for patient respondents, while higher medication-related cost was cited as the most concerning barrier to implementation by providers. Overall, these findings indicate enthusiasm for the development of long-acting injectable antimalarials to provide individual delivery method options across age groups.

The New Era of Long-Acting Antiretroviral Therapy: When and Why to Make the Switch

PURPOSE OF REVIEW

Despite the availability of safe and effective oral combination antiretroviral therapy, barriers to maintaining viral suppression remain a challenge to ending the HIV epidemic. Long-acting injectable antiretroviral therapy was developed as an alternative to daily oral therapy. This review summarizes the current literature on the efficacy of long-acting cabotegravir plus rilpivirine for the treatment of HIV-1, reasons to switch to injectable therapy, and barriers to switching.

RECENT FINDINGS

Long-acting cabotegravir plus rilpivirine is safe and effective in maintaining HIV-1 virologic suppression. Ideal candidates for switching to long-acting cabotegravir plus rilpivirine are virologically suppressed on oral regimens with good adherence and no history of virologic failure or baseline resistance. Indications to switch to injectable therapy include patient preference, the potential for improved adherence, and avoidance of adverse effects. Implementation research is needed to assess and overcome system barriers. Long-acting cabotegravir plus rilpivirine is a novel alternative to oral antiretrovirals, with the potential to improve adherence and quality of life in people with HIV.

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.

Global HIV control: is the glass half empty or half full?

The massive scale-up of HIV treatment and prevention over the past two decades has resulted in important reductions in new infections and mortality globally. Reduction in HIV incidence, however, has been unequal, with worsening epidemics in regions where the reach and scale of HIV control programmes have been insufficient, especially in eastern Europe, central Asia, the Middle East, north Africa, and Latin America where HIV epidemics are concentrated among key populations, including people who inject drugs, men who have sex with men, transgender people, and some minority racial and ethnic groups. The global state of the HIV pandemic highlights disparities in HIV control efforts and provides a roadmap for what should be done, including investment to better implement the effective HIV prevention and treatment tools that are available, but whose adoption and scale-up are not yet sufficient to get us close to an AIDS-free generation. To achieve the full potential of global HIV control, we call for urgent, evidence-informed implementation at scale of our existing and novel HIV prevention and treatment strategies in ways that are better, faster, more efficient, and cost-effective, especially in key populations and regions where the HIV pandemic continues to expand.

Projected Benefits of Long-Acting Antiretroviral Therapy in Nonsuppressed People With Human Immunodeficiency Virus Experiencing Adherence Barriers

Background

In a demonstration project, long-acting, injectable cabotegravir-rilpivirine (CAB-RPV) achieved viral suppression in a high proportion of people with HIV (PWH) who were virologically nonsuppressed with adherence barriers. We projected the long-term impact of CAB-RPV for nonsuppressed PWH experiencing adherence barriers.

Methods

Using the Cost-Effectiveness of Preventing AIDS Complications (CEPAC) model, we compared 3 strategies: (1) standard of care oral integrase inhibitor-based ART (INSTI); (2) INSTI-based ART with supportive social services ("wraparound services" [WS]) (INSTI/WS); and (3) CAB-RPV with WS (CAB-RPV/WS). Model outcomes included viral suppression (%) and engagement in care (%) at 3 years, and life expectancy (life-years [LYs]). Base case cohort characteristics included mean age of 47y (standard deviation [SD], 10y), 90% male at birth, and baseline mean CD4 count 150/µL (SD, 75/µL). Viral suppression at 3 months was 13% (INSTI), 28% (INSTI/WS), and 60% (CAB-RPV/WS). Mean loss to follow-up was 28/100 person-years (PY) (SD, 2/100 PY) without WS and 16/100 PY (SD, 1/100 PY) with WS.

Results

Projected viral suppression at 3 years would vary widely: 16% (INSTI), 38% (INSTI/WS), and 44% (CAB-RPV/WS). Life expectancy would be 7.4 LY (INSTI), 9.0 LY (INSTI/WS), and 9.4 LY (CAB-RPV/WS). Projected benefits over oral ART would be greater for PWH initiating CAB-RPV/WS at lower CD4 counts. Across plausible key parameter ranges, CAB-RPV/WS would improve viral suppression and life expectancy compared with oral INSTI strategies.

Conclusions

These model-based results support that long-acting injectable CAB-RPV with extensive support services for nonsuppressed PWH experiencing adherence barriers is likely to increase viral suppression and improve survival. A prospective study to provide further evidence is needed.

Preference for daily oral pills over long-acting antiretroviral therapy options among people with HIV

OBJECTIVE

To examine the characteristics of people with HIV (PWH) who prefer remaining on daily oral antiretroviral therapy (ART), rather than switching to long-acting ART (LA-ART).

DESIGN

Building upon a discrete choice experiment (DCE), we examined characteristics of individuals who always selected their current daily oral tablet regimen over either of two hypothetical LA-ART options presented in a series of 17 choice tasks.

METHODS

We used LASSO to select sociodemographic, HIV-related, and other health-related predictors of preferring current therapy over LA-ART, and logistic regression to measure the associations with those characteristics.

RESULTS

Among 700 PWH in Washington State and Atlanta, Georgia, 11% of participants ( n  = 74) chose their current daily treatment over LA-ART in all DCE choice tasks. We found that people with lower educational attainment, good adherence, more aversion to injections, and who participated from Atlanta to be more likely to prefer their current daily regimen over LA-ART.

CONCLUSIONS

Gaps in ART uptake and adherence remain, and emerging LA-ART treatments show promise to address these challenges and help a larger portion of PWH to achieve viral suppression, but preferences for these new treatments are understudied. Our results show that certain drawbacks of LA-ART may help to maintain demand for daily oral tablets, especially for PWH with certain characteristics. Some of these characteristics (lower educational attainment and Atlanta participation) were also associated with a lack of viral suppression. Future research should focus on overcoming barriers that impact preferences for LA-ART among those patients who could benefit most from this innovation.

Preclinical Evaluation of Long-Acting Emtricitabine Semi-Solid Prodrug Nanoparticle Formulations

Long-acting injectable (LAI) formulations promise to deliver patient benefits by overcoming issues associated with non-adherence. A preclinical assessment of semi-solid prodrug nanoparticle (SSPN) LAI formulations of emtricitabine (FTC) is reported here. Pharmacokinetics over 28 days were assessed in Wistar rats, New Zealand white rabbits, and Balb/C mice following intramuscular injection. Two lead formulations were assessed for the prevention of an HIV infection in NSG-cmah^-/- humanised mice to ensure antiviral activities were as anticipated according to the pharmacokinetics. Cmax was reached by 12, 48, and 24 h in rats, rabbits, and mice, respectively. Plasma concentrations were below the limit of detection (2 ng/mL) by 21 days in rats and rabbits, and 28 days in mice. Mice treated with SSPN formulations demonstrated undetectable viral loads (700 copies/mL detection limit), and HIV RNA remained undetectable 28 days post-infection in plasma, spleen, lung, and liver. The in vivo data presented here demonstrate that the combined prodrug/SSPN approach can provide a dramatically extended pharmacokinetic half-life across multiple preclinical species. Species differences in renal clearance of FTC mean that longer exposures are likely to be achievable in humans than in preclinical models.

The role of tunneling nanotubes during early stages of HIV infection and reactivation: implications in HIV cure

Tunneling nanotubes (TNTs), also called cytonemes or tumor microtubes, correspond to cellular processes that enable long-range communication. TNTs are plasma membrane extensions that form tubular processes that connect the cytoplasm of two or more cells. TNTs are mostly expressed during the early stages of development and poorly expressed in adulthood. However, in disease conditions such as stroke, cancer, and viral infections such as HIV, TNTs proliferate, but their role is poorly understood. TNTs function has been associated with signaling coordination, organelle sharing, and the transfer of infectious agents such as HIV. Here, we describe the critical role and function of TNTs during HIV infection and reactivation, as well as the use of TNTs for cure strategies.

Long-acting antiretrovirals and HIV treatment adherence

Intramuscular injection of long-acting cabotegravir and rilpivirine is a novel, long-acting antiretroviral therapy (ART) combination approved for use as a fully suppressive regimen for people living with HIV. Long-acting cabotegravir with rilpivirine ART has reduced required dosing frequency from once daily to once every month or every 2 months injections. This new era of long-acting ART, which includes other antiretrovirals and formulations in various stages of clinical development, holds tremendous promise to change the standard of HIV treatment. Although long-acting ART has high potential to be revolutionary in the landscape of HIV care, prevention, and treatment cascade, more data are needed to substantiate its efficacy and cost-effectiveness among patients at risk of non-adherence and across age groups, pregnancy, and post partum. Advocacy efforts and policy changes to optimise a sustained, high-quality, equitable reach of long-acting ART, especially in low-income and middle-income countries where most people living with HIV reside, are needed to realise the full benefits of long-acting ART.

Access to a novel first-line single-tablet HIV antiretroviral regimen in Affordable Care Act Marketplace plans, 2018-2020

BACKGROUND

A pillar of the United States' Ending the HIV Epidemic (EHE) initiative is to rapidly provide antiretroviral therapy (ART) in order to achieve HIV viral suppression. However, insurance benefit design can impede ART access. The primary objective of this study is to understand how Affordable Care Act (ACA) Marketplace qualified health plan (QHP) formularies responded to two new ART single tablet regimens (STRs): dolutegravir/abacavir/lamivudine (DTG/ABC/3TC; approved in 2014) and bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF; approved in 2018).

METHODS

We conducted a descriptive study of individual and small group QHPs to assess coverage, cost sharing (coinsurance vs. copay), specialty tiering, prior authorization, and out-of-pocket (OOP) costs for DTG/ABC/3TC and BIC/FTC/TAF. All individual and small group QHPs offered in state ACA Marketplaces from 2018-2020 were identified using plan-level formulary data from Ideon linked to end-of-year data from Robert Wood Johnson Foundation's Individual Market Health Insurance Exchange (HIX).

RESULTS

For 2018, 2019, and 2020, respectively, we identified 19,533, 17,007, and 21,547 QHPs. While DTG/ABC/3TC coverage was above 91% from 2018-2020, BIC/FTC/TAF coverage improved from 60 to 86%. Coverage of BIC/FTC/TAF improved in EHE priority jurisdictions from 73 to 90% driven by increased coverage with coinsurance. Although BIC/FTC/TAF had a higher wholesale acquisition cost than DTG/ABC/3TC, monthly OOP cost trends differed regionally in the Midwest but did not differ by EHE priority jurisdiction status.

CONCLUSIONS

QHP coverage of STRs is heterogeneous across the US. While coverage of BIC/FTC/TAF increased over time, many QHPs in EHE priority jurisdictions required coinsurance. Access to new ART regimens may be slowed by delayed QHP coverage and benefit design.

Injectable Long-Acting Cabotegravir-Rilpivirine Therapy for People Living With HIV/AIDS: Addressing Implementation Barriers From the Start

ABSTRACT

Injectable cabotegravir and rilpivirine (CAB/RPV), administered bimonthly by a medical provider, is convenient and improves privacy and medication management. One year after approval, myriad implementation barriers threaten the access and sustainability of this life-saving innovation: (1) eligibility issues (viral suppression, drug resistance, and failed oral regimens); (2) injection requires medical provider and transportation to facility; (3) strict medication adherence; (4) life challenges-mental health, homelessness, joblessness; and (5) lack of insurance and high cost. Universal implementation of CAB/RPV calls for social, human, and health organizations to partner and provide HIV continuum of care and prevention services to facilitate CAB/RPV access and maintenance and for transparent health insurance billing practices to abate uncertainty concerning CAB/RPV's classification as a pharmaceutical or medical benefit and related cost implications.

Long-Acting Antiretroviral Drug Therapy in Adolescents: Current Status and Future Prospects

Approximately 50% of human immunodeficiency virus (HIV)-infected adolescents fail to achieve complete viral suppression, largely due to nonadherence to their antiretroviral drug regimens. Numerous personal, financial, and societal barriers contribute to nonadherence, which may lead to the development of HIV drug resistance. Long-acting antiretroviral drugs hold the promise of improved adherence because they remove the need for swallowing one or more pills daily. Cabotegravir (an integrase strand transfer inhibitor) and rilpivirine (a non-nucleoside reverse transcriptase inhibitor) can now be intramuscularly co-administered to HIV-infected adolescents every 4-8 weeks if they are virologically suppressed and without resistance mutations to cabotegravir or rilpivirine. Adverse effects are few and non-severe. Widespread use of this complete antiretroviral therapy may be limited by drug costs, need for sites and skilled personnel who can administer the injections, and ethical challenges. Other long-acting medications and new antiretroviral therapy delivery systems are under active investigation and show great promise.

First Demonstration Project of Long-Acting Injectable Antiretroviral Therapy for Persons With and Without Detectable Human Immunodeficiency Virus (HIV) Viremia in an Urban HIV Clinic

BACKGROUND

Long-acting injectable antiretroviral therapy (LAI-ART) is approved for treatment-naive or experienced people with human immunodeficiency virus (HIV; PWH) based on trials that only included participants with viral suppression. We performed the first LAI-ART demonstration project to include PWH unable to achieve or maintain viral suppression due to challenges adhering to oral ART.

METHODS

Ward 86 is a large HIV clinic in San Francisco that serves publicly insured and underinsured patients. We started patients on LAI-ART via a structured process of provider referral, multidisciplinary review (MD, RN, pharmacist), and monitoring for on-time injections. Inclusion criteria were willingness to receive monthly injections and a reliable contact method.

RESULTS

Between June 2021 and April 2022, 51 patients initiated LAI-ART, with 39 receiving at least 2 follow-up injections by database closure (median age, 46 years; 90% cisgender men, 61% non-White, 41% marginally housed, 54% currently using stimulants). Of 24 patients who initiated injections with viral suppression (median CD4 cell count, 706 cells/mm3), 100% (95% confidence interval [CI], 86%-100%) maintained viral suppression. Of 15 patients who initiated injections with detectable viremia (median CD4 cell count, 99 cells/mm3; mean log10 viral load, 4.67; standard deviation, 1.16), 12 (80%; 95% CI, 55%-93%) achieved viral suppression, and the other 3 had a 2-log viral load decline by a median of 22 days.

CONCLUSIONS

This small demonstration project of LAI-ART in a diverse group of patients with high levels of substance use and marginal housing demonstrated promising early treatment outcomes, including in those with detectable viremia due to adherence challenges. More data on LAI-ART in hard-to-reach populations are needed.

Perspectives on long-acting injectable HIV antiretroviral therapy at an alternative care site: a qualitative study of people with HIV experiencing substance use and/or housing instability

INTRODUCTION

Adherence to daily oral antiretroviral therapy (ART) and regular clinic appointments can be challenging for individuals who experience adverse social determinants of health. Long-acting injectable ART administered outside of traditional clinic settings may be a promising solution to adherence barriers, but additional research is needed to assess patients' perspectives. This study assessed perspectives of people living with HIV (PLWH) who had difficulty with adherence to traditional HIV care models and evaluated feasibility and acceptability of receiving a long-acting ART injection at a location outside of a traditional HIV clinic to address barriers to HIV care.

METHODS

Qualitative interviews (n = 26) were conducted with PLWH who had experienced barriers to adherence. Participants were referred to the study by staff from Project Trust, a drop in harm reduction and sexually transmitted infection/HIV clinic. The interviews were conducted between May and November 2021. Interviews were recorded, professionally transcribed, coded, and analyzed qualitatively using the integrated-Promoting Action on Research Implementation in Health Services framework.

RESULTS

We identified 6 main themes regarding the acceptability of receiving a long-acting injection to treat HIV, and the acceptability and feasibility of receiving injections at an alternative care site. Participants specified that they: (1) have a general understanding about their HIV care and the importance of ART adherence, (2) prefer a long-acting injection over a daily pill regimen, (3) expressed concerns about injection safety and efficacy, (4) had specific logistical aspects around the delivery of long-acting injections, including location of injection administration, that they believed would improve their ability to adhere, (5) have confidence that they can become undetectable and then complete the oral lead-in required to begin receiving the injection, and (6) see potential barriers that remain a concern for successful adherence to long-acting injections.

CONCLUSION

To better treat HIV among people who are living with challenging social determinants of health, interventions that include a long-acting injection in a non-traditional care setting may prove to be a promising treatment option.

Long-Acting Injectable Therapy for People with HIV: Looking Ahead with Lessons from Psychiatry and Addiction Medicine

Long-acting injectable antiretroviral medications are new to HIV treatment. People with HIV may benefit from a treatment option that better aligns with their preferences, but could also face new challenges and barriers. Authors from the fields of HIV, substance use treatment, and mental health collaborated on this commentary on the issues surrounding equitable implementation and uptake of LAI ART by drawing lessons from all three fields. We employ a socio-ecological framework beginning at the policy level and moving through the community, organizational, interpersonal, and patient levels. We look at extant literature on the topic as well as draw from the direct experience of our clinician-authors.

Acceptance Rate and Reasons for Rejection of Long Acting Injectable Antiretrovirals

In January 2021, cabotegravir/rilpivirine, the first extended-release injectable regimen for the treatment of Human Immunodeficiency Virus (HIV) was approved. Long-acting injections have the potential to improve adherence and viral suppression. We analyzed the acceptance rate of, and reasons for declining to switch to, the new regimen. During routine appointments, 102 people living with HIV (PLWH) were presented with information on the new medication and asked if they would like to switch from their current regimen. If they declined to switch, they were asked why. Sixty-nine percent of respondents declined to switch, with frequency of injections as the primary reason. Patients indicated they would be willing to switch if the interval between injections was longer. Forty percent of the patients accepting the injectable anti-retrovirals (ARVs) were not on any other medications. Barriers to switching to long-acting injectable ARVs include the need for more frequent provider visits, aversion to needles, and a perceived lack of evidence supporting the new medication.

The experienced positive and negative influence of HIV on quality of life of people with HIV and vulnerable to HIV in the Netherlands

This qualitative study aimed to explore the experienced influence of HIV on the quality of life (QoL) of people with HIV (PHIV) and key populations without but are vulnerable to HIV in the Netherlands. We conducted and thematically analyzed interviews with 29 PHIV and 13 participants from key populations without HIV (i.e., men who have sex with men). PHIV and key populations shared positive meaningful experiences regarding HIV, i.e., feeling grateful for ART, life, and the availability of PrEP, being loved and supported in the light of HIV, and providing support to the community. Negative predominant experiences regarding HIV were described by both PHIV and key populations as the negative effects of ART, challenges with regards to disclosing HIV, social stigmatization, and self-stigma. It remains important to support HIV community organizations in their efforts to reduce social stigmatization and to continue improving biomedical interventions for HIV.

Realizing the promise of long-acting antiretroviral treatment strategies for individuals with HIV and adherence challenges: an illustrative case series

BACKGROUND

Adherence to antiretroviral treatment (ART) remains the cornerstone of optimal HIV outcomes, including viral suppression (VS), immune recovery, and decreased transmission risk. For many people with HIV (PWH), particularly those with early-acquired HIV, structural, behavioral, and cognitive barriers to adherence and competing priorities related to life events may be difficult to overcome, resulting in nonadherence. Long-acting injectable antiretroviral therapies (LAI-ART) may be a useful strategy to overcome some of these barriers. However, to date, the approved LAI-ART strategies (e.g., cabotegravir and rilpivirine (CAB/RPV)) have targeted those who have already attained viral suppression, precluding their use in the 40% of adolescents and young adults (AYA) that VS has eluded.

CASE PRESENTATION

Ms. X is a 30-year-old woman with perinatally-acquired HIV and barriers to adherence. Despite many interventions, she remained persistently viremic, with resultant immune suppression and multiple comorbid opportunistic conditions, and viral load (VL) > 10,000,000 copies/ml. Given her longstanding history of poor adherence to an oral regimen, a switch to monthly intramuscular (IM) injections and biweekly infusions of ibalizumab were initiated leading to decreased viral load to 8,110 copies/ml within two weeks. Ms. H is a 33-year-old woman with cognitive limitations due to childhood lead poisoning. Her viral load trajectory took a downward turn, precipitated by various life events, remaining elevated despite intensive case management. Initiation of LAI-ART (CAB/RPV) in this patient led to an undetectable VL (< 20 copies/ml) within two months of treatment initiation. Miss Y. is a 37-year-old woman with perinatally-acquired HIV and chronic challenges with nonadherence and longstanding immunosuppression with CD4 < 200 cells/mm³ for > 5 years. She received a 1-month oral lead-in (OLI) of cabotegravir/rilpivirine, followed by the injectable loading dose. She has since adhered to all her monthly dosing appointments, sustained VS, and transitioned to a bi-monthly injection schedule.

CONCLUSION

These three individuals with HIV (perinatally and non-perinatally acquired) with longstanding nonadherence and persistent viremia were successfully initiated on LAI-ART through the process of care coordination and the collective efforts of the care team, highlighting the barriers, challenges, and the multidisciplinary coordination needed to assure successful implementation of this strategy for the most vulnerable of patients.

What Clinicians Need to Know About the Development of Long-Acting Formulations

We encourage readers of this Supplement to find articles that are relevant to the current and future practice of infectious diseases medicine. Access to long-acting products and formulations in low- and middle-income countries remains a key determinant of the impact of these advances on global health.

Agent-based model projections for reducing HIV infection among MSM: Prevention and care pathways to end the HIV epidemic in Chicago, Illinois

Our objective is to improve local decision-making for strategies to end the HIV epidemic using the newly developed Levers of HIV agent-based model (ABM). Agent-based models use computer simulations that incorporate heterogeneity in individual behaviors and interactions, allow emergence of systemic behaviors, and extrapolate into the future. The Levers of HIV model (LHM) uses Chicago neighborhood demographics, data on sex-risk behaviors and sexual networks, and data on the prevention and care cascades, to model local dynamics. It models the impact of changes in local preexposure prophylaxis (PrEP) and antiretroviral treatment (ART) (ie, levers) for meeting Illinois' goal of "Getting to Zero" (GTZ) -reducing by 90% new HIV infections among men who have sex with men (MSM) by 2030. We simulate a 15-year period (2016-2030) for 2304 distinct scenarios based on 6 levers related to HIV treatment and prevention: (1) linkage to PrEP for those testing negative, (2) linkage to ART for those living with HIV, (3) adherence to PrEP, (4) viral suppression by means of ART, (5) PrEP retention, and (6) ART retention. Using tree-based methods, we identify the best scenarios at achieving a 90% HIV infection reduction by 2030. The optimal scenario consisted of the highest levels of ART retention and PrEP adherence, next to highest levels of PrEP retention, and moderate levels of PrEP linkage, achieved 90% reduction by 2030 in 58% of simulations. We used Bayesian posterior predictive distributions based on our simulated results to determine the likelihood of attaining 90% HIV infection reduction using the most recent Chicago Department of Public Health surveillance data and found that projections of the current rate of decline (2016-2019) would not achieve the 90% (p = 0.0006) reduction target for 2030. Our results suggest that increases are needed at all steps of the PrEP cascade, combined with increases in retention in HIV care, to approach 90% reduction in new HIV diagnoses by 2030. These findings show how simulation modeling with local data can guide policy makers to identify and invest in efficient care models to achieve long-term local goals of ending the HIV epidemic.

Are Patients and Their Providers Talking About Long-Acting Injectable Antiretroviral Therapy? Penetration into Clinical Encounters at Three U.S. Care Sites

Use of long-acting injectable antiretroviral therapy depends on patient awareness, provider discussion, and patient willingness to use. We conducted a postvisit survey with patients at 3 HIV clinics in San Francisco, Chicago, and Atlanta in May 2021 to assess for inequities in these early implementation phases.

Cabenuva: the last FDA-approved drug to treat HIV

INTRODUCTION

The conventional combination antiretroviral therapy (cART) besides all its benefits, exhibited poor adherence to daily pill administration, life-long treatment period and emergence of viral resistance. The development of long-acting (LA) drugs have changed the management of common medical conditions for human immunodeficiency virus (HIV). Cabenuva is the first LA antiretroviral injectable drug composed of nano-formulation of cabotegravir (CAB) and rilpivirine (RPV).

AREAS COVERED

In this review article, we aim to have a brief overview of results of major clinical trials which administrated cabenuva for patients considering the efficacy and safety profiles. Moreover, we discuss about CAB and RPV chemical structure, mechanism of action, ‎activity against drug-sensitive and resistant HIV and pharmacodynamics/ pharmacokinetics properties.

EXPERT OPINION

Based on the results of the ATLAS and FLAIR trials, cabenuva regimen once-monthly has shown equal effectivity to oral cART in maintaining HIV-1 suppression in patients. Furthermore, ATLAS-2M study revealed the non-inferiority of cabenuva regimen every 8 weeks compared to every 4 weeks. The injectable LA ART, reduces the number of treatment intake as well as increases adherence especially in patients with HIV-related stigma. Administration of extended-release agents probably minimize the risk of treatment-related toxicity and resistance related to sub-optimal adherence to oral ART, so cabenuva can be suggested as a suitable alternative for HIV infection control in current era.

Implications of Bariatric Surgery on the Pharmacokinetics of Antiretrovirals in People Living with HIV

Bariatric surgery is increasingly applied among people living with HIV to reduce obesity and the associated morbidity and mortality. In people living with HIV, sufficient antiretroviral exposure and activity should always be maintained to prevent development of resistance and disease progression. However, bariatric surgery procedures bring various gastrointestinal modifications including changes in gastric volume, and acidity, gastrointestinal emptying time, enterohepatic circulation and delayed entry of bile acids. These alterations may affect many aspects of antiretroviral pharmacokinetics. Some drug characteristics may result in subtherapeutic exposure and the potential related risk of treatment failure and resistance. Antiretrovirals that require low pH, administration of fatty meals, longer intestinal exposure, and an enterohepatic recirculation for their absorption may be most impacted by bariatric surgery procedures. Additionally, some antiretrovirals can interact with the polyvalent cations in supplements or drugs inhibiting gastric acid, thereby preventing their use as these comedications are commonly prescribed post-bariatric surgery. Predicting pharmacokinetics on the basis of drug characteristics solely proved to be challenging, therefore pharmacokinetic studies remain crucial in this population. Here, we discuss general implications of bariatric surgery on antiretroviral outcomes in people living with HIV as well as drug properties that are relevant for the choice of antiretroviral treatment in this special patient population. Additionally, we summarise studies that evaluated the pharmacokinetics of antiretrovirals post-bariatric surgery. Finally, we performed a comprehensive analysis of theoretical considerations and published pharmacokinetic and pharmacodynamic data to provide recommendations on antiretrovirals for people living with HIV undergoing bariatric surgery.

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.

Miniature mass spectrometer-based point-of-care assay for cabotegravir and rilpivirine in whole blood

HIV prevention and treatment with injectable cabotegravir and/or rilpivirine administered once every 4 to 8 weeks is an attractive alternative to daily therapy. Prescribed dosage and drug concentrations in plasma are based on patient data collected in clinical trials, but actual patients are expected to exhibit more variability in drug concentrations, which is important to quantify. Here, we demonstrate the first quantitative point-of-care assay with a miniature mass spectrometer to assess these drug concentrations in whole blood. Quantitative performance is obtained using paper spray ionization in combination with tandem mass spectrometry (MS/MS) in the clinically relevant concentration range of both drugs. Limits of quantitation (LoQs) of cabotegravir and rilpivirine are measured to be 750 ng/mL and 20 ng/mL, respectively. The assay turnaround time is < 4 min, and strong linear relationships are established between MS/MS responses and concentration, with percentage of relative standard deviations (RSDs) that are <15% at concentrations above the LoQs. The speed, portability, low power consumption, and specificity offered by the miniature instrument should make it an appropriate platform for measuring drug concentrations in a walk-in clinic using small volumes of patient blood.

Drug-Drug Interactions in People Living with HIV at Risk of Hepatic and Renal Impairment: Current Status and Future Perspectives

Despite the advancement of antiretroviral therapy (ART) for the treatment of human immunodeficiency virus (HIV), drug–drug interactions (DDIs) remain a relevant clinical issue for people living with HIV receiving ART. Antiretroviral (ARV) drugs can be victims and perpetrators of DDIs, and a detailed investigation during drug discovery and development is required to determine whether dose adjustments are necessary or coadministrations are contraindicated. Maintaining therapeutic ARV plasma concentrations is essential for successful ART, and changes resulting from potential DDIs could lead to toxicity, treatment failure, or the emergence of ARV‐resistant HIV. The challenges surrounding DDI management are complex in special populations of people living with HIV, and often lack evidence‐based guidance as a result of their underrepresentation in clinical investigations. Specifically, the prevalence of hepatic and renal impairment in people living with HIV are between five and 10 times greater than in people who are HIV‐negative, with each condition constituting approximately 15% of non‐AIDS‐related mortality. Therapeutic strategies tend to revolve around the treatment of risk factors that lead to hepatic and renal impairment, such as hepatitis C, hepatitis B, hypertension, hyperlipidemia, and diabetes. These strategies result in a diverse range of potential DDIs with ART. The purpose of this review was 2‐fold. First, to summarize current pharmacokinetic DDIs and their mechanisms between ARVs and co‐medications used for the prevention and treatment of hepatic and renal impairment in people living with HIV. Second, to identify existing knowledge gaps surrounding DDIs related to these special populations and suggest areas and techniques to focus upon in future research efforts.

A new paradigm for antiretroviral delivery: long-acting cabotegravir and rilpivirine for the treatment and prevention of HIV

PURPOSE OF REVIEW

Cabotegravir (CAB) and rilpivirine (RPV) is the first long-acting injectable antiretroviral therapy (ART) option approved for virologically suppressed adults with HIV-1. In addition, long-acting CAB is a promising agent for HIV preexposure prophylaxis (PrEP). This review focuses on phase 3 clinical trial results and implementation considerations for these long-acting ART and PrEP strategies.

RECENT FINDINGS

Long-acting CAB and RPV administered every 4 weeks demonstrated noninferiority to oral ART through week 96 in both the ATLAS and FLAIR studies, whereas ATLAS-2M found similar efficacy through 96 weeks when the long-acting injectable ART was administered every 8 weeks instead of every 4 weeks. For prevention, two phase 3 trials were stopped early due to fewer incident HIV infections in participants receiving long-acting CAB every 8 weeks compared with daily oral tenofovir disoproxil fumarate-emtricitabine for PrEP. The long-acting therapies were well tolerated across all clinical trials.

SUMMARY

Clinical trial results support the use of long-acting CAB for HIV PrEP and long-acting CAB and RPV as a switch strategy for adults with HIV-1 who are first virologically suppressed with oral ART. Implementation challenges persist, and data are urgently needed in populations who may benefit most from long-acting therapy, including adolescents, pregnant individuals, and those with barriers to medication adherence.

Evaluating Islatravir Administered Via Microneedle Array Patch for Long-Acting HIV Pre-exposure Prophylaxis Using Physiologically Based Pharmacokinetic Modelling

BACKGROUND AND OBJECTIVES

Technologies for long-acting administration of antiretrovirals (ARVs) for the prevention and treatment of HIV are at the forefront of research initiatives aiming to tackle issues surrounding drug adherence with the current standard of once-daily oral administration. Islatravir (ISL) is an emerging ARV that shows promising characteristics for long-acting prevention and treatment both orally as well as through alternative routes of administration. Microneedle array patches (MAPs) are a pain-free and discreet transdermal delivery technology that offer extended-release administration of nanoparticulate drugs. This study aimed to utilise physiologically based pharmacokinetic (PBPK) modelling to predict the pharmacokinetics resulting from ISL administered via MAP and to identify key MAP characteristics required to sustain effective concentrations over extended dosing intervals.

METHODS

A PBPK model describing the conversion of ISL to ISL-triphosphate (ISL-TP) and its whole-body disposition was developed and verified against observed clinical data for orally administered ISL in healthy adults. An intradermal PBPK model was integrated with the ISL PBPK model to predict the dose and nanoparticle release rate required for MAP administration strategies capable of achieving a minimum ISL-TP target concentration of 0.05 pmol/10⁶ PBMCs over extended dosing intervals. MAP design was limited to a maximum therapeutic area of 20 cm² with a dose loading of 4.09 mg/cm² and a minimum duration of 3 months. Due to the lack of available clinical data, a range of nanoparticle release rates and MAP bioavailability scenarios were simulated to provide an overview of potential clinical outcomes.

RESULTS

The ISL PBPK model was successfully verified, with predicted vs observed ratios falling within 0.5-2-fold. ISL MAP doses ranging from 15 to 80 mg were predicted to sustain ISL-TP concentrations above the minimum target concentration at 3, 6 and 12 months after administration. Nanoparticle release rate and MAP bioavailability were found to have a major impact on whether dosing strategies achieved the criteria. Minimum doses of 15 mg and 60 mg with a nanoparticle release rate of 0.0005 h^-1 and bioavailability ranging from 25 to 100% were predicted to achieve effective ISL-TP concentrations up to 3 and 6 months, respectively. Doses of 15 mg and 30 mg with a nanoparticle release rate of 0.0005 h^-1 were also able to attain the target concentration up to 6 months after MAP administration, albeit with a minimum bioavailability of 75% and 50%, respectively. Furthermore, when simulating a bioavailability of 100%, an 80 mg ISL MAP was predicted to sustain ISL-TP concentrations above the minimum target concentration up to 12 months after administration.

CONCLUSIONS

The ISL PBPK model successfully predicted ISL and ISL-TP pharmacokinetics across a range of orally administered regimens. The integrated intradermal PBPK model outlined optimal MAP dose and nanoparticle release rates for effective ISL-TP concentrations up to 12 months, providing justification for further investigation of ISL as a candidate for MAP administration.

Preferences of Persons with or at Risk for Hepatitis C for Long-Acting Treatments

BACKGROUND

Whereas safe, curative treatments for hepatitis C virus (HCV) have been available since 2015, there are still 58 million infected persons worldwide, and global elimination may require new paradigms. We sought to understand the acceptability of long-acting HCV treatment approaches.

METHODS

A cross-sectional, 43-question survey was administered to 1457 individuals with HCV or at risk of HCV at 28 sites in 9 countries to assess comparative interest in a variety of long-acting strategies in comparison to oral pills.

RESULTS

Among HCV-positive participants, 37.7% most preferred an injection, 5.6% an implant, and 6% a gastric residence device, as compared to 50.8% who stated they would most prefer taking 1 to 3 pills per day. When compared directly to taking pills, differences were observed in the relative preference for an injection based on age (p<0.001), location (p<0.001), and prior receipt of HCV treatment (p=0.005), but not sex. When an implant was compared to pills, greater preference was represented by women (p=0.01) and adults of younger ages (p=0.012 per 5 years). Among participants without HCV, 49.5% felt that injections are stronger than pills, and 34.7% preferred taking injections to pills. Among those at-risk participants who had received injectable medications in the past, 123 out of 137 (89.8%) expressed willingness to receive one in the future.

CONCLUSIONS

These data point to high acceptability of long-acting treatments, which for a substantial minority, might even be preferred to pills for the treatment of HCV infection. Long-acting treatments for HCV infection might contribute to global efforts to eliminate hepatitis C.