Pharmacokinetics and Drug-Drug Interactions of Long-Acting Intramuscular Cabotegravir and Rilpivirine

Low cabotegravir trough concentrations without oral lead-in in patients with HIV-1 switching to long-acting cabotegravir and rilpivirine

In a cohort of 72 consecutive virologically-suppressed patients with HIV-1 switching to long-acting cabotegravir and rilpivirine, we observed low cabotegravir trough concentrations 1 and 3 months after the first injection, with a significant association with no oral lead-in at 1 month [odds ratio (OR) = 6.3 [95% confidence interval (CI) 1.7-29.5], P = 0.01] and three months (OR = 5.6 [95% CI 1.3-29.7], P = 0.03), and with high BMI at 1 month (OR = 1.3 [95% CI 1.1-1.6], P = 0.007).

Physiologically based Pharmacokinetic Model Validated to Enable Predictions Of Multiple Drugs in a Long-acting Drug-combination Nano-Particles (DcNP): Confirmation with 3 HIV Drugs, Lopinavir, Ritonavir, and Tenofovir in DcNP Products

Drug-Combination Nanoparticles (DcNP) are a novel drug delivery system designed for synchronized delivery of multiple drugs in a single, long-acting, and targeted dose. Unlike depot formulations, slowly releasing drug at the injection site into the blood, DcNP allows multiple-drug-in-combination to collectively distribute from the injection site into the lymphatic system. Two distinct classes of long-acting injectables products are proposed based on pharmacokinetic mechanisms. Class I involves sustained release at the injection site. Class II involves a drug-carrier complex composed of lopinavir, ritonavir, and tenofovir uptake and retention in the lymphatic system before systemic access as a part of the PBPK model validation. For clinical development, Class II long-acting drug-combination products, we leverage data from 3 nonhuman primate studies consisting of nine PK datasets: Study 1, varying fixed-dose ratios; Study 2, short multiple dosing with kinetic tails; Study 3, long multiple dosing (chronic). PBPK validation criteria were established to validate each scenario for all drugs. The models passed validation in 8 of 9 cases, specifically to predict Study 1 and 2, including PK tails, with ritonavir and tenofovir, fully passing Study 3 as well. PBPK model for lopinavir in Study 3 did not pass the validation due to an observable time-varying and delayed drug accumulation, which likely was due to ritonavir's CYP3A inhibitory effect building up during multiple dosing that triggered a mechanism-based drug-drug interaction (DDI). Subsequently, the final model enables us to account for this DDI scenario.

Two-drug regimens for the treatment of HIV in Africa

Two-drug regimens for the treatment of HIV are increasingly available. The oral regimen of dolutegravir plus lamivudine is recommended as a preferred option in multiple national guidelines but is not currently included in WHO HIV treatment guidelines nor widely used in Africa. Long-acting injectable cabotegravir and rilpivirine is being rolled out in the USA, Europe, and Australia but its use in sub-Saharan Africa is currently restricted to clinical trials. Given the increasing life expectancy, rising prevalence of non-communicable diseases, and resulting polypharmacy among people living with HIV, there are potential advantages to the use of two-drug regimens, particularly in African women, adolescents, and older adults. This Viewpoint reviews existing evidence and highlights the risks, benefits, and key knowledge gaps for the use of two-drug regimens in settings using the public health approach in Africa. We suggest that a two-drug regimen of dolutegravir and lamivudine can be safely used as a switch option for virologically suppressed individuals in settings using the public health approach once chronic hepatitis B has been excluded. Individuals with HIV who are switched to two-drug regimens should receive a full course of hepatitis B vaccinations. More efficacy data is needed to support dolutegravir plus lamivudine combination in the test and treat approach, and long-acting cabotegravir and rilpivirine in the public health system in sub-Saharan Africa.

Population Pharmacokinetics of Cabotegravir Following Oral Administration and Long-Acting Intramuscular Injection in Real-World People with HIV

Long-acting cabotegravir has been studied mainly in the stringent framework of clinical trials, which does not necessarily reflect the situation of people with HIV (PWH) in routine clinical settings. The present population pharmacokinetic analysis aims to build real-world reference percentile curves of cabotegravir concentrations, accounting for patient-related factors that may affect cabotegravir exposure. The second objective is to simulate whether dosing interval adjustments of cabotegravir could be considered in specific subpopulations. Overall, 238 PWH contributed to 1,038 cabotegravir levels (186 during the initial oral administration phase and 852 after intramuscular injection). Cabotegravir pharmacokinetics was best described using a one-compartment model with distinct first order-absorption for oral and intramuscular administrations, and identical volume and clearance. Our model showed almost 40% faster absorption and 30% higher clearance than previously reported, resulting in a time to steady-state of 8 months and an elimination half-life of 4.6 weeks for long-acting cabotegravir. Sex and body mass index significantly influenced absorption, and bodyweight affected clearance. Model-based simulations showed that cabotegravir trough concentrations in females were 25% lower 4 weeks after the intramuscular loading dose, but 42% higher during the late maintenance phase. Finally, simulations indicated that in females, despite significantly higher cabotegravir concentrations, longer intervals between injections may not consistently ensure levels above the 4-fold protein-adjusted 90% inhibitory target concentration.

An update on drug-drug interactions in older adults living with human immunodeficiency virus (HIV)

INTRODUCTION

People with HIV are living longer due to advances in antiretroviral therapy. With improved life expectancy comes an increased lifetime risk of comorbid conditions - such as cardiovascular disease and cancer - and polypharmacy. Older adults, particularly those living with HIV, are more vulnerable to drug interactions and adverse effects, resulting in negative health outcomes.

AREA COVERED

Antiretrovirals are involved in many potential drug interactions with medications used to treat common comorbidities and geriatric conditions in an aging population of people with HIV. We review the mechanisms and management of significant drug-drug interactions involving antiretroviral medications and non-antiretroviral medications commonly used among older people living with HIV. The management of these interactions may require dose adjustments, medication switches to alternatives, enhanced monitoring, and considerations of patient- and disease-specific factors.

EXPERT OPINION

Clinicians managing comorbid conditions among older people with HIV must be particularly vigilant to side effect profiles, drug-drug interactions, pill burden, and cost when optimizing treatment. To support healthier aging among people living with HIV, there is a growing need for antiretroviral stewardship, multidisciplinary care models, and advances that promote insight into the correlations between an individual, their conditions, and their medications.

Long-acting cabotegravir pharmacokinetics with and without oral lead-in for HIV PrEP

Long-acting cabotegravir is approved for pre-exposure prophylaxis and combination HIV treatment, both initiated with optional short-term oral lead-in (OLI). We evaluated the impact of OLI on long-acting cabotegravir pharmacokinetics. Cabotegravir plasma concentrations were compared between HIV-positive participants initiating injections with (n = 278) or without (n = 110) OLI in phase III treatment study FLAIR and in HIV-negative participants using OLI (n = 263) in pivotal pre-exposure prophylaxis studies HPTN 083 and HPTN 084. Cabotegravir pharmacokinetic profiles were simulated in three populations (assigned-male-at-birth, 50%-assigned-female-at-birth, and assigned-female-at-birth) under three scenarios: first injection given (A) 1 or (B) 3 days after final OLI dose (OLI-injection gap) or (C) without OLI. The PK objective was 80% of participants achieving 4× in vitro protein-adjusted 90% maximal inhibitory concentration (PA-IC90) and 50% achieving 8× PA-IC90. Observed trough concentrations (Cτ) were similar with and without OLI (P > 0.3). With a 3-day OLI-injection gap, simulated pre-injection Cτ remained above PK objective. Approximately 1-2 weeks after the first injection, simulated PK profiles became nearly identical among all scenarios. Without OLI, it was predicted that 80% of participants achieve 4× PA-IC90 in 1.2, 1.8, and 2.8 days after the first injection in each population, respectively, and 50% achieve 8× PA-IC90 in 1.4, 2.1, and 3.8 days, respectively. Observed long-acting cabotegravir exposure was similar with or without OLI, supporting optional OLI use. Cabotegravir exposure was predicted to remain above PK objective for OLI-injection gaps of ≤3 days and rapidly achieve PK objective after first injection without OLI. Findings are consistent between assigned-male-at-birth and assigned-female-at-birth populations.This study is registered with ClinicalTrials.gov as NCT02720094.

Rilpivirine and cabotegravir trough concentrations in people with HIV on long-term treatment with long-acting injectable antiretrovirals

OBJECTIVE

Large inter-individual variability in the pharmacokinetics of rilpivirine and cabotegravir has been reported in the first weeks after starting long-acting injectable (LAI) therapy. Here, we assessed the distribution of rilpivirine and cabotegravir trough concentrations in people with HIV (PWH) on long-term LAI treatment.

METHODS

Adult PWH treated with LAI for at least 32 weeks with an assessment of drug plasma trough concentrations were considered. The proportion of rilpivirine and cabotegravir plasma trough concentrations below four-times the protein-adjusted concentrations required for 90% inhibition of viral replication (4×PA-IC90) was estimated.

RESULTS

Sixty-seven PWH were identified. LAI treatment duration was 216 ± 80 weeks (range 32-320 weeks). Cabotegravir concentrations were associated with lower inter-individual variability compared with rilpivirine (45% versus 84%; P < 0.05). No differences were found in rilpivirine (160 ± 118 versus 189 ± 81 ng/mL; P = 0.430) and cabotegravir (1758 ± 807 versus 1969 ± 802 ng/mL; P = 0.416) trough concentrations in males (n = 55) versus females (n = 12). A non-significant trend for lower cabotegravir concentrations was found in PWH with a body mass index >30 kg/m2 (n = 9) versus non-obese participants (1916 ± 905 versus 1606 ± 576 ng/mL; P = 0.131). Three out of the 67 PWH had at least one drug concentration <4×PA-IC90: 100% of PWH had undetectable HIV viral load.

CONCLUSIONS

At steady state, optimal systemic exposure of cabotegravir and rilpivirine was found in most PWH; cabotegravir trough concentrations were associated with lower inter-individual variability compared with rilpivirine. The study was not powered to assess the contribution of sex and/or body weight on LAI exposure due to the small number of females and obese PWH included.

Development of a physiologically-based pharmacokinetic model to simulate the pharmacokinetics of intramuscular antiretroviral drugs

There is growing interest in the use of long-acting (LA) injectable drugs to improve treatment adherence. However, their long elimination half-life complicates the conduct of clinical trials. Physiologically-based pharmacokinetic (PBPK) modeling is a mathematical tool that allows to simulate unknown clinical scenarios for LA formulations. Thus, this work aimed to develop and verify a mechanistic intramuscular PBPK model. The framework describing the release of a LA drug from the depot was developed by including both the physiology of the injection site and the physicochemical properties of the drug. The framework was coded in Matlab® 2020a and implemented in our existing PBPK model for the verification step using clinical data for LA cabotegravir, rilpivirine, and paliperidone. The model was considered verified when the simulations were within twofold of observed data. Furthermore, a local sensitivity analysis was conducted to assess the impact of various factors relevant for the drug release from the depot on pharmacokinetics. The PBPK model was successfully verified since all predictions were within twofold of observed clinical data. Peak concentration, area under the concentration-time curve, and trough concentration were sensitive to media viscosity, drug solubility, drug density, and diffusion layer thickness. Additionally, inflammation was shown to impact the drug release from the depot. The developed framework correctly described the release and the drug disposition of LA formulations upon intramuscular administration. It can be implemented in PBPK models to address pharmacological questions related to the use of LA formulations.

Drug Exposure of Long-Acting Cabotegravir and Rilpivirine in Older People With Human Immunodeficiency Virus: A Pharmacokinetic Modeling Study

Background

The life expectancy of people with human immunodeficiency virus (PWH) has significantly increased, thanks to combined antiretrovirals with improved potency and tolerability. One further step has been achieved with the development of long-acting (LA) injectable antiretrovirals, which allow for infrequent dosing. However, the pharmacokinetics of LA antiretrovirals has been poorly characterized in older PWH, as they are generally excluded from trials. We performed virtual studies using physiologically based pharmacokinetic (PBPK) modeling to determine the anticipated exposure of LA cabotegravir/rilpivirine in older individuals.

Methods

Our PBPK model was verified against available observed data for LA cabotegravir and rilpivirine. Cohorts of virtual individuals aged 20-50, 50-65, or 65-85 years were generated to simulate the exposure of LA cabotegravir/rilpivirine for each age group. The fold changes in trough concentration (Cmin) and in drug exposure (area under the time-concentration curve [AUC]) were determined for older relative to young individuals.

Results

The verified PBPK models predicted an increase in exposure within the 0.8-1.25 fold range for monthly LA cabotegravir/rilpivirine. The Cmin and AUC were predicted to be 29% and 26% higher in older compared with young adults for LA cabotegravir administered bimonthly (every 2 months) and 46% and 41% higher for LA rilpivirine bimonthly. The Cmin and AUC of LA cabotegravir and rilpivirine were predicted to be modestly increased in female compared with male individuals for all age groups.

Conclusions

LA cabotegravir/rilpivirine exposure and trough concentrations are predicted to be higher in older than in young PWH; thus, older adults could have a lower risk to present suboptimal concentrations during the dosing interval.

Direct switch from an efavirenz-based regimen to intramuscular long-acting cabotegravir plus rilpivirine: A case report

Switching from oral antiretroviral treatment to intramuscular (IM) cabotegravir (CAB) + rilpivirine (RPV) has an optional oral lead-in to ensure tolerability. The British HIV Association guidelines advise against directly switching from oral antiretroviral (ART) combinations containing strong/moderate cytochrome inducers like efavirenz (EFV) to IM CAB + RPV. EFV has a prolonged elimination half-life, leading to a residual induction of UGT1A1 and CYP3A4 after discontinuation. These enzymes are responsible for CAB and RPV metabolism and their induction might lead to sub-optimal concentrations of CAB and RPV, risking drug resistance. When switching from EFV to oral CAB + RPV, the ATLAS and ATLAS 2M studies showed reduced RPV concentrations but with maintained viral suppression during the oral lead-in and subsequent long-acting injectable (LAI) phases. Also, a recent pharmacokinetic modelling study indicated reduced RPV concentrations, without viral implication, when switching from EFV to IM CAB + RPV. However, there are limited real-world data on direct switching from EFV-based therapy to long-acting IM CAB + RPV. We describe a case where oral intake was impossible in a critical care scenario, switching from emitricitabine/tenofovir-DF (FTC/TDF) 200/245 mg + 600 mg EFV to IM CAB + RPV for treatment optimisation.

Lamivudine, Doravirine, and Cabotegravir Downregulate the Expression of Human Endogenous Retroviruses (HERVs), Inhibit Cell Growth, and Reduce Invasive Capability in Melanoma Cell Lines

This study explores the impact of antiretroviral administration on the expression of human endogenous retroviruses (HERVs), cell growth, and invasive capability of human melanoma cell lines in culture. We investigated three antiretrovirals-lamivudine, doravirine, and cabotegravir-in A375, FO-1, and SK-Mel-28, BRAF-mutated, and in MeWo, P53-mutated, melanoma cell lines. The findings indicate a general capability of these drugs to downregulate the expression of HERV-K Pol and Env genes and hinder cell viability, mobility, and colony formation capacity of melanoma cells. The antiretroviral drugs also demonstrate selectivity against malignant cells, sparing normal human epithelial melanocytes. The study reveals that the integrase inhibitor cabotegravir is particularly effective in inhibiting cell growth and invasion across different cell lines in comparison with lamivudine and doravirine, which are inhibitors of the viral reverse transcriptase enzyme. The investigation further delves into the molecular mechanisms underlying the observed effects, highlighting the potential induction of ferroptosis, apoptosis, and alterations in cell cycle regulatory proteins. Our findings showed cytostatic effects principally revealed in A375, and SK-Mel-28 cell lines through a downregulation of retinoblastoma protein phosphorylation and/or cyclin D1 expression. Signs of ferroptosis were detected in both A375 cells and FO-1 cells by a decrease in glutathione peroxidase 4 and ferritin expression, as well as by an increase in transferrin protein levels. Apoptosis was also detected in FO-1 and SK-Mel-28, but only with cabotegravir treatment. Moreover, we explored the expression and activity of the stimulator of interferon genes (STING) protein and its correlation with programmed death-ligand 1 (PD-L1) expression. Both the STING activity and PD-L1 expression were decreased, suggesting that the antiretroviral treatments may counteract the detrimental effects of PD-L1 expression activation through the STING/interferon pathway triggered by HERV-K. Finally, this study underscores the potential therapeutic significance of cabotegravir in melanoma treatment. The findings also raise the prospect of using antiretroviral drugs to downregulate PD-L1 expression, potentially enhancing the therapeutic responses of immune checkpoint inhibitors.

Improving Adherence to the Target Window for Cabotegravir + Rilpivirine Long-Acting Injections Through the CHORUS™ App and Web Portal: A Cluster Randomized Trial

BACKGROUND

We evaluated the impact of the CHORUS™ app on adherence to the cabotegravir and rilpivirine long-acting injectable (CAB + RPV LAI) monthly injections schedule.

METHODS

Healthcare centers (HCCs) were randomized to access CHORUS™ CAB + RPV LAI features (intervention) or not (control) from 01OCT2021-31JAN2022. Target window adherence (maintenance injections ≤7 days before/after target day) was assessed with multivariate logistic regression (generalized estimating equations).

RESULTS

CAB + RPV LAI was administered to 188 and 79 individuals at intervention and control HCCs, respectively. Intervention was not associated with improved target window adherence (adjusted odds ratio: 0.61 [95% CI: 0.30-1.25]). However, app use was associated with increased odds of adherence compared to no app use among all intervention HCCs (2.98 [1.26-7.06]) and at smaller HCCs (3.58 [1.31-9.80]).

CONCLUSIONS

While access to CHORUS™ CAB + RPV LAI features did not improve target window adherence, app use did, especially at smaller HCCs which may not have established LAI management procedures.

TRIAL REGISTRATION

https://clinicaltrials.gov/show/NCT04863261.

Fixed-dose antiretroviral combinations in children living with human immunodeficiency virus type 1 (HIV-1): a systematic review

Fixed-Dose antiretroviral Combinations (FDCs) are the most used drug regimes in adult patients with human-immunodeficiency virus 1 infection, since they increase adherence to antiretroviral therapy and enable good quality of life. The European AIDS Clinical Society guidelines recommend the use of FDCs in paediatrics. However, the use of FDCs in paediatric population is restricted since studies in children and adolescents are mostly conducted in small sample sizes and are heterogeneous in settings and design. This systematic review aims to summarize the current knowledge about the use of FDCs in paediatric population, highlighting the relevant outcomes regarding efficacy and effectiveness, adherence, safety, and adverse events of these regimens.

Long-Acting Cabotegravir/Rilpivirine Concentrations in Combination With Intravenous Rifampin: A Case Report

As antiretroviral therapy advancements focus on long-acting medications, there is a need to assess the potential impact of drug-drug interactions. We present a real-world case of long-acting cabotegravir/rilpivirine co-administered with intravenous rifampin. The combination resulted in both cabotegravir and rilpivirine concentrations falling below 4 times the protein-adjusted IC90.

Efficacy and safety of long-acting cabotegravir compared with daily oral tenofovir disoproxil fumarate plus emtricitabine to prevent HIV infection in cisgender men and transgender women who have sex with men 1 year after study unblinding: a secondary analysis of the phase 2b and 3 HPTN 083 randomised controlled trial

BACKGROUND

Injectable cabotegravir was superior to daily oral tenofovir disoproxil fumarate plus emtricitabine for HIV prevention in two clinical trials. Both trials had the primary aim of establishing the HIV prevention efficacy of long-acting injectable cabotegravir pre-exposure prophylaxis (PrEP) compared with tenofovir disoproxil fumarate plus emtricitabine daily oral PrEP. Long-acting PrEP was associated with diagnostic delays and integrase strand-transfer inhibitor (INSTI) resistance. This report presents findings from the first unblinded year of the HIV Prevention Trials Network (HPTN) 083 study.

METHODS

The HPTN 083 randomised controlled trial enrolled HIV-uninfected cisgender men and transgender women at elevated HIV risk who have sex with men, from 43 clinical research sites in Africa, Asia, Latin America, and the USA. Inclusion criteria included: a negative HIV serological test at the screening and study entry, undetectable HIV RNA levels within 14 days of study entry, age 18 years or older, overall good health as determined by clinical and laboratory evaluations, and a creatinine clearance of 60 mL/min or higher. Participants were randomly allocated to receive long-acting injectable cabotegravir or daily oral tenofovir disoproxil fumarate plus emtricitabine PrEP. After study unblinding, participants remained on their original regimen awaiting an extension study. HIV infections were characterised retrospectively at a central laboratory. Here we report the secondary analysis of efficacy and safety for the first unblinded year. The primary outcome was incident HIV infection. Efficacy analyses were done on the modified intention-to-treat population using a Cox regression model. Adverse events were compared across treatment groups and time periods (blinded vs unblinded). This trial is registered with ClinicalTrials.gov, NCT02720094.

FINDINGS

Of the 4488 participants who contributed person-time to the blinded analysis, 3290 contributed person-time to the first unblinded year analysis between May 15, 2020, and May 14, 2021. Updated HIV incidence in the blinded phase was 0·41 per 100 person-years for long-acting injectable cabotegravir PrEP and 1·29 per 100 person-years for daily oral tenofovir disoproxil fumarate plus emtricitabine PrEP (hazard ratio [HR] 0·31 [95% CI 0·17-0·58], p=0·0003). HIV incidence in the first unblinded year was 0·82 per 100 person-years for long-acting PrEP and 2·27 per 100 person-years for daily oral PrEP (HR 0·35 [0·18-0·69], p=0·002). Adherence to both study products decreased after study unblinding. Additional infections in the long-acting PrEP group included two with on-time injections; three with one or more delayed injections; two detected with long-acting PrEP reinitiation; and 11 more than 6 months after their last injection. Infection within 6 months of cabotegravir exposure was associated with diagnostic delays and INSTI resistance. Adverse events were generally consistent with previous reports; incident hypertension in the long-acting PrEP group requires further investigation.

INTERPRETATION

Long-acting injectable cabotegravir PrEP retained high efficacy for HIV prevention in men and transgender women who have sex with men during the first year of open-label follow-up, with a near-identical HR for HIV risk reduction between long-acting injectable cabotegravir and daily oral tenofovir disoproxil fumarate plus emtricitabine PrEP during the first year after unblinding compared with the blinded period. Extended follow-up further defined the risk period for diagnostic delays and emergence of INSTI resistance.

FUNDING

Division of AIDS at the National Institute of Allergy and Infectious Diseases, ViiV Healthcare, and Gilead Sciences.

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.

Clinical Relevance of Drug Interactions in People Living with Human Immunodeficiency Virus on Antiretroviral Therapy-Update 2022: Systematic Review

BACKGROUND

The clinical outcomes of antiretroviral drugs may be modified through drug interactions; thus, it is important to update the drug interactions in people living with HIV (PLHIV).

AIM

To update clinically relevant drug interactions in PLHIV on antiretroviral therapy with novel drug interactions published from 2017 to 2022.

METHODS

A systematic review in Medline/PubMed database from July 2017 to December 2022 using the Mesh terms antiretroviral agents and drug interactions or herb-drug interactions or food-drug interactions. Publications with drug interactions in humans, in English or Spanish, and with full-text access were retrieved. The clinical relevance of drug interactions was grouped into five levels according to the gravity and probability of occurrence.

RESULTS

A total of 366 articles were identified, with 219 (including 87 citation lists) were included, which allowed for the identification of 471 drug interaction pairs; among them, 291 were systematically reported for the first time. In total 42 (14.4%) and 137 (47.1%) were level one and two, respectively, and 233 (80.1%) pairs were explained with the pharmacokinetic mechanism. Among these 291 pairs, protease inhibitors (PIs) and ritonavir/cobicistat-boosted PIs, as well as integrase strand transfer inhibitors (InSTIs), with 70 (24.1%) and 65 (22.3%) drug interaction pairs of levels one and two, respectively, were more frequent.

CONCLUSIONS

In PLHIV on antiretroviral therapy, we identify 291 drug interaction pairs systematically reported for the first time, with 179 (61.5%) being assessed as clinically relevant (levels one and two). The pharmacokinetic mechanism was the most frequently identified. PIs, ritonavir/cobicistat-boosted PIs, and InSTIs were the antiretroviral groups with the highest number of clinically relevant drug interaction pairs (levels one and two).

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.

Pillars of long-term antiretroviral therapy success

BACKGROUND

Meeting the challenge of antiretroviral therapy (ART) whose efficacy can last a lifetime requires continuous updating of the virological, pharmacological, and quality of life outcomes to be pursued and a continuous review of literature data on the efficacy and tolerability of new drugs and therapeutic strategies.

METHODS

With the aim of identifying open questions and answers about the current controversies in modern ART, we adapted the Design Thinking methodology to the needs of the design phase of a scientific article, involving a team of experts in HIV care.

RESULTS

Five main pillars of treatment success were discussed: sustained virologic suppression over time; immunological recovery; pharmacological attributes; long-term tolerability and safety of ART; and people's satisfaction and quality of life. The definition of the outcomes to be achieved in each thematic area and the tools to achieve them were reviewed and discussed.

CONCLUSIONS

Long-term treatment success should be intended as a combination of HIV-RNA suppression, immune recovery, and high quality of life. To achieve this, the regimen should be well-tolerated, with high potency, genetic barrier, and forgiveness, and should be tailored by a person-centered perspective, based on individual needs, preferences, and therapeutic history.

Long-acting lenacapavir protects macaques against intravenous challenge with simian-tropic HIV

BACKGROUND

Long-acting subcutaneous lenacapavir (LEN), a first-in-class HIV capsid inhibitor approved by the US FDA for the treatment of multidrug-resistant HIV-1 with twice yearly dosing, is under investigation for HIV-1 pre-exposure prophylaxis (PrEP). We previously derived a simian-tropic HIV-1 clone (stHIV-A19) that encodes an HIV-1 capsid and replicates to high titres in pigtail macaques (PTM), resulting in a nonhuman primate model well-suited for evaluating LEN PrEP in vivo.

METHODS

Lenacapavir potency against stHIV-A19 in PTM peripheral blood mononuclear cells in vitro was determined and subcutaneous LEN pharmacokinetics were evaluated in naïve PTMs in vivo. To evaluate the protective efficacy of LEN PrEP, naïve PTMs received either a single subcutaneous injection of LEN (25 mg/kg, N = 3) or vehicle (N = 4) 30 days before a high-dose intravenous challenge with stHIV-A19, or 7 daily subcutaneous injections of a 3-drug control PrEP regimen starting 3 days before stHIV-A19 challenge (N = 3).

FINDINGS

In vitro, LEN showed potent antiviral activity against stHIV-A19, comparable to its potency against HIV-1. In vivo, subcutaneous LEN displayed sustained plasma drug exposures in PTMs. Following stHIV-A19 challenge, while all vehicle control animals became productively infected, all LEN and 3-drug control PrEP animals were protected from infection.

INTERPRETATION

These findings highlight the utility of the stHIV-A19/PTM model and support the clinical development of long-acting LEN for PrEP in humans.

FUNDING

Gilead Sciences as part of a Cooperative Research and Development Agreement between Gilead Sciences and Frederick National Lab; federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. 75N91019D00024/HHSN261201500003I; NIH grant R01AI078788.

Drug-drug interactions between COVID-19 therapeutics and antiretroviral treatment: the evidence to date

INTRODUCTION

With new effective treatments for SARS-CoV-2, patient outcomes have greatly improved. However, new medications bring a risk of drug interactions with other medications. People living with HIV (PLWH) are at particular risk for these interactions due to heightened risk of immunosuppression, polypharmacy, and overlap in affected organs. It is critical to identify drug interactions are a significant barrier to care for PLWH. Establishing a better understanding of the pharmacologic relationships between COVID-19 therapies and antiretrovirals will improve patient-centered care in COVID-19.

AREAS COVERED

Potential drug-drug interactions between Human Immunodeficiency Virus (HIV) and COVID-19 treatments are detailed and reviewed here. The mechanisms seen in these interactions include alterations in metabolic enzymes, drug transporters, pharmacoenhancement, and organ toxicities. We also review the limitations and solutions that can be used to combat drug-drug interactions between these two disease states.

EXPERT OPINION

While current drug interactions are relatively mild between HIV and COVID-19 therapies, improvements in identifying these beforehand must take place as new therapies are approved. Antiretroviral therapy (ART) is essential in PLWH and must be maintained when treating COVID-19. As advancements in care occur, there is the possibility that newly approved drugs may have additional unknown interactions.

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.

Gynoid Fat Distribution and Adipocyte Trapping May Explain Virological Failure With Intramuscular Long-Acting Cabotegravir and Rilpivirine

Intramuscular long-acting antiretroviral drugs can improve adherence to lifelong antiretroviral treatment. Nevertheless, adipose tissue thickness and distribution play a critical role with injectable drugs. We describe a virological failure with cabotegravir and rilpivirine in a Black African woman with human immunodeficiency virus type 1 with gynoid fat distribution (ie, adipose tissue prevailing in the pelvis and hip area) and body mass index <30 kg/m².

Extended Analysis of HIV Infection in Cisgender Men and Transgender Women Who Have Sex with Men Receiving Injectable Cabotegravir for HIV Prevention: HPTN 083

HPTN 083 demonstrated that injectable cabotegravir (CAB) was superior to oral tenofovir disoproxil fumarate-emtricitabine (TDF-FTC) for HIV prevention in cisgender men and transgender women who have sex with men. We previously analyzed 58 infections in the blinded phase of HPTN 083 (16 in the CAB arm and 42 in the TDF-FTC arm). This report describes 52 additional infections that occurred up to 1 year after study unblinding (18 in the CAB arm and 34 in the TDF-FTC arm). Retrospective testing included HIV testing, viral load testing, quantification of study drug concentrations, and drug resistance testing. The new CAB arm infections included 7 with CAB administration within 6 months of the first HIV-positive visit (2 with on-time injections, 3 with ≥1 delayed injection, and 2 who restarted CAB) and 11 with no recent CAB administration. Three cases had integrase strand transfer inhibitor (INSTI) resistance (2 with on-time injections and 1 who restarted CAB). Among 34 CAB infections analyzed to date, diagnosis delays and INSTI resistance were significantly more common in infections with CAB administration within 6 months of the first HIV-positive visit. This report further characterizes HIV infections in persons receiving CAB preexposure prophylaxis and helps define the impact of CAB on the detection of infection and the emergence of INSTI resistance.

Cabotegravir: The First Long-Acting Injectable for HIV Preexposure Prophylaxis

OBJECTIVE

Review the pharmacology, pharmacokinetics, efficacy, safety, and role of long-acting injectable cabotegravir (CAB-LA) in HIV preexposure prophylaxis (PrEP).

DATA SOURCES

A literature search was performed using PubMed and Google Scholar (2012 to April 2022) with the search terms cabotegravir, preexposure prophylaxis, and PrEP. Other resources included abstracts presented at recent conferences, the manufacturer's Web site, prescribing information, and review articles.

STUDY SELECTION AND DATA EXTRACTION

All English-language articles of studies assessing the efficacy and safety of CAB-LA for PrEP were included.

DATA SYNTHESIS

CAB-LA is the first long-acting injectable therapy approved for HIV-1 PrEP in both men and women. It is a suspension given intramuscularly every other month. CAB-LA has been shown to be more effective than daily oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) in preventing HIV-1 infection among high-risk individuals. Two phase 3 trials were stopped early on the basis of superior efficacy of CAB-LA. The most common adverse effects were injection site reactions (ISRs), although they tended to decrease over time, and few participants in clinical trials discontinued use due to ISRs.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

CAB-LA may be particularly useful for individuals with known adherence problems to oral therapy, those with renal impairment, and those with decreased bone mineral density. However, CAB-LA is more expensive than generic TDF/FTC and may be associated with weight gain.

CONCLUSIONS

CAB-LA is the first long-acting injectable agent for HIV PrEP. It is more effective than oral TDF/FTC, is well-tolerated aside from ISRs, and has few clinically significant drug-drug interactions.

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.

Considerations for the Use of Long-Acting and Extended-Release Agents During Pregnancy and Lactation

Long-acting agents hold significant promise for treating and preventing common illnesses, including infections. Pharmacokinetic and safety data during pregnancy and lactation are often unavailable for new drugs; these data are vital to facilitate optimal drug use by pregnant and lactating women and women who may conceive. In this commentary, we summarize the circumstances in which pregnant and lactating women are likely to use and benefit from long-acting agents. We focus on long-acting formulations of small molecules (rather than biologics such as monoclonal antibodies) and on several infections of global importance (human immunodeficiency virus, tuberculosis, malaria, and hepatitis C). We discuss pregnancy pharmacokinetic/pharmacodynamic and potential safety and efficacy considerations pertaining to the use of long-acting agents in pregnancy and lactation. Finally, we summarize existing preclinical and pregnancy pharmacokinetic data that are available (or expected in the near future) for several agents that are under development or approved, and how key research gaps may be addressed.

An evaluation of long-acting cabotegravir + rilpivirine for the treatment of virologically suppressed adults living with HIV

INTRODUCTION

HIV is a global disease that has seen significant improvements in care over the past decades. Despite improvements, treatments for maintaining suppression are complex for patients and include two to three oral medications. The approval of intramuscular cabotegravir (CAB) and rilpivirine (RPV) offers a new therapeutic modality with the opportunity of a longer dosing frequency. The data from recent trials including FLAIR and ATLAS have shown non-inferiority in treatment based on the current standard of care. This approval has the potential to simplify patient medication regimens, while maintaining virologic suppression in HIV-1 patients.

AREAS COVERED

Cabotegravir + rilpivirine's recent approval for the treatment of HIV and its significant impact it may have on people living with HIV.

EXPERT OPINION

Cabotegravir + rilpivirine is a long-acting injectable that can be used for patients who want to reduce the frequency antiretroviral administration. CAB+RPV allows for virologic suppression with monthly or less often administration, but comes with a significant price point, although injection site reactions may limit utility for many patients.

Bioevaluation of a dual PI3K/HDAC inhibitor for the treatment of diffuse large B-cell lymphoma

The synergistic anti-tumor effect by simultaneous inhibitions of PI3K and HDAC has been verified to provide the rationality of PI3K/HDAC dual inhibitors for cancer treatment. Notably, the outstanding effect of PI3K/HDAC dual inhibitors against DLBCL has been paid much attention, especially for RR-DLBCL. Our previously reported 4-methylquinazoine scaffold based PI3K/HDAC dual inhibitors could suppress the growth of solid tumors and hematologic malignancies both in vitro and in vivo, validating the potential as new therapeutic agents for cancer. In this research, we further investigated the anti-tumor activity of one of our compounds against DLBCL cell lines and in vivo zebrafish xenograft model as well as the underlying mechanism, hoping to provide a novel therapeutic agent for treating DLBCL.

Major revision version 11.0 of the European AIDS Clinical Society Guidelines 2021

BACKGROUND

The European AIDS Clinical Society (EACS) Guidelines were revised in 2021 for the 17th time with updates on all aspects of HIV care.

KEY POINTS OF THE GUIDELINES UPDATE

Version 11.0 of the Guidelines recommend six first-line treatment options for antiretroviral treatment (ART)-naïve adults: tenofovir-based backbone plus an unboosted integrase inhibitor or plus doravirine; abacavir/lamivudine plus dolutegravir; or dual therapy with lamivudine or emtricitabine plus dolutegravir. Recommendations on preferred and alternative first-line combinations from birth to adolescence were included in the new paediatric section made with Penta. Long-acting cabotegravir plus rilpivirine was included as a switch option and, along with fostemsavir, was added to all drug-drug interaction (DDI) tables. Four new DDI tables for anti-tuberculosis drugs, anxiolytics, hormone replacement therapy and COVID-19 therapies were introduced, as well as guidance on screening and management of anxiety disorders, transgender health, sexual health for women and menopause. The sections on frailty, obesity and cancer were expanded, and recommendations for the management of people with diabetes and cardiovascular disease risk were revised extensively. Treatment of recently acquired hepatitis C is recommended with ongoing risk behaviour to reduce transmission. Bulevirtide was included as a treatment option for the hepatitis Delta virus. Drug-resistant tuberculosis guidance was adjusted in accordance with the 2020 World Health Organization recommendations. Finally, there is new guidance on COVID-19 management with a focus on continuance of HIV care.

CONCLUSIONS

In 2021, the EACS Guidelines were updated extensively and broadened to include new sections. The recommendations are available as a free app, in interactive web format and as an online pdf.

A Pharmacokinetic Dose-Optimization Study of Cabotegravir and Bictegravir in a Mouse Pregnancy Model

Animal pregnancy models can be useful tools to study HIV antiretroviral safety and toxicity and to perform mechanistic studies that are not easily performed in humans. Utilization of clinically relevant dosing in these models improves the relevance of the findings. Cabotegravir and bictegravir are new integrase strand transfer inhibitors (INSTIs), recently approved for the treatment of people living with HIV. Studies of these drugs in pregnancy are very limited. The objective of this study was to perform a dose-optimization study of cabotegravir and bictegravir in a mouse pregnancy model with the goal of determining the dose that would yield plasma drug concentrations similar those observed in humans. Pregnant mice were administered increasing doses of cabotegravir or bictegravir in combination with emtricitabine and tenofovir by oral gavage from gestational day 11.5 to 15.5. Drug concentrations in the maternal plasma at 1 h and 24 h post drug administration and in the amniotic fluid at 1 h post drug administration were determined using high-performance liquid chromatography coupled with tandem mass spectrometry. A review of cabotegravir and bictegravir human pharmacokinetic studies are also reported. We hope these data will encourage studies of HIV antiretroviral safety/toxicity and mechanistic studies in animal pregnancy models.

Real-Life Therapeutic Concentration Monitoring of Long-Acting Cabotegravir and Rilpivirine: Preliminary Results of an Ongoing Prospective Observational Study in Switzerland

SHCS#879 is an ongoing Switzerland-wide multicenter observational study conducted within the Swiss HIV Cohort Study (SHCS) for the prospective follow-up of people living with HIV (PLWH) receiving long-acting injectable cabotegravir-rilpivirine (LAI-CAB/RPV). All adults under LAI-CAB/RPV and part of SHCS are enrolled in the project. The study addresses an integrated strategy of treatment monitoring outside the stringent frame of controlled clinical trials, based on relevant patient characteristics, clinical factors, potential drug-drug interactions, and measurement of circulating blood concentrations. So far, 91 blood samples from 46 PLWH have been collected. Most individuals are less than 50 years old, with relatively few comorbidities and comedications. The observed concentrations are globally in accordance with the available values reported in the randomized clinical trials. Yet, low RPV concentrations not exceeding twice the reported protein-adjusted 90% inhibitory concentration have been observed. Data available at present confirm a considerable between-patient variability overall. Based on the growing amount of PK data accumulated during this ongoing study, population pharmacokinetic analysis will characterize individual concentration-time profiles of LAI-CAB/RPV along with their variability in a real-life setting and their association with treatment response and tolerability, thus bringing key data for therapeutic monitoring and precision dosage adjustment of this novel long-acting therapy.

Cabotegravir: The first long-acting injectable for HIV pre-exposure prophylaxis

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

The purpose of this article is to review the pharmacology, efficacy, and safety of the integrase inhibitor cabotegravir for HIV pre-exposure prophylaxis, including data from clinical trials.

SUMMARY

A narrative review was performed by searching PubMed/MEDLINE databases to identify relevant articles published between March 2014 and December 2021 using the keyword terms cabotegravir and Apretude and the search strings "long-acting injectable AND human immunodeficiency virus" and "pre-exposure prophylaxis AND human immunodeficiency virus." All relevant English-language articles evaluating the pharmacology, efficacy, or safety of cabotegravir in humans for HIV pre-exposure prophylaxis were included. Additional data were obtained from prescribing information, references of identified articles, and abstracts from scientific meetings. Cabotegravir has been approved by the Food and Drug Administration and is considered both safe and effective for HIV pre-exposure prophylaxis. It is the first long-acting injectable medication approved for this indication. Phase 3 clinical trials have demonstrated the noninferiority of cabotegravir to currently recommended oral once-daily dosing regimens. Injection-site reactions were common in clinical trials of cabotegravir and occurred in up to 81% of trial participants. Costs associated with the long-acting injectable formulation must also be considered.

CONCLUSION

Cabotegravir is a novel bimonthly, injectable option for pre-exposure HIV prophylaxis for high-risk adolescents and adults weighing at least 35 kg.

Drug-drug interactions of Integrase Strand Transfer Inhibitors among older people living with HIV: Interazioni farmacologiche degli inibitori delle integrase tra le persone anziane che vivono con HIV

The advancement of Human Immunodeficiency Virus (HIV) treatment improves the life expectancy of HIV-positive individuals. People living with HIV have more polypharmacy and drug-drug interactions than those without HIV. Integrase strand transfer inhibitors (INSTIs) are the newest class commonly used for HIV treatment. There are five INSTIs currently approved by the Food and Drug Administration, including raltegravir, elvitegravir, dolutegravir, bictegravir, and cabotegravir. INSTIs class contributes to better safety and efficacy profile, making them the preferred or recommended antiretroviral regimens in HIV treatment guidelines worldwide. Despite the shared mechanism of action, INSTIs differ in pharmacokinetics, contributing to different drug-drug interactions. This review summarized the potential drug interactions of INSTIs and the management of the drug interactions in clinical practice.

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.

Formulation of Cabotegravir Loaded Gold Nanoparticles: Optimization, Characterization to In-Vitro Cytotoxicity Study

The effective and preventive treatment of HIV is one of the difficult challenges worldwide. It requires the development of an effective prophylactic strategy to prevent HIV/AIDS. This study aimed to synthesize Cabotegravir (CAB)-biodegradable gold (Au) nanoparticles by using pectin as a reducer and stabilizer. CAB-GNPs were prepared by the slightly modified Turkevich method. CAB-GNPs were optimized using Box Behnken design for independent variables gold chloride (A), pectin (B) and pH range (C). The effects of independent variables were observed on particle size (Y1) and encapsulation efficiency (Y2). The results of the study revealed that the optimized nanoparticles (GLN7) had a particle size of 3.9 ± 0.1 nm and encapsulation efficiency of 97.2 ± 3.9%. TEM study showed the spherical shape particles. The in-vitro drug release revealed 62.1 ± 0.5% release of CAB in simulated gastric buffer (pH 1.2) and 45.5 ± 2.8% in physiological buffer (pH 7.4). In-vitro cytotoxicity study and antibacterial activity depicted the safety of the prepared NPs by showing lesser toxicity than pure CAB. From the results, our experimental outcomes concluded that CAB gold nanoparticles composed of pectin may constitute a preferred embodiment for the delivery of CAB.

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.

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.

HIV Prevention Utilizing Long-acting Injectables

Pre-exposure prophylaxis (PrEP) is an essential component in ending the HIV pandemic. Unfortunately, PrEP uptake has not been optimal to date. This is due to various reasons, one of which is adherence. Long-acting injectables may help to overcome this barrier. This brief review discusses the long-acting injectables currently in use for PrEP (cabotegravir) and HIV treatment (cabotegravir and lenacapavir), as well as those currently undergoing clinical trials. Other promising agents are being studied, including islatravir and broadly neutralizing monoclonal antibodies. Furthermore, agents currently used for HIV treatment will likely be evaluated in preclinical and clinical studies for their use as PrEP agents.

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.

Advances in the development of HIV integrase strand transfer inhibitors

HIV-1 integrase (IN) is a key enzyme in viral replication that catalyzes the covalent integration of viral cDNA into the host genome. Currently, five HIV-1 IN strand transfer inhibitors (INSTIs) are approved for clinical use. These drugs represent an important addition to the armamentarium for antiretroviral therapy. This review briefly illustrates the development history of INSTIs. The characteristics of the currently approved INSTIs, as well as their future perspectives, are critically discussed.

Dexamethasone is a dose-dependent perpetrator of drug-drug interactions: implications for use in people living with HIV

Global use of dexamethasone in COVID-19 patients has revealed a poor understanding of the drug-drug interaction (DDI) potential of dexamethasone, particularly with antiretroviral agents (ARVs). Dexamethasone is both a substrate and a dose-dependent inducer of cytochrome P450 3A4 (CYP3A4). As many ARVs are substrates and/or inhibitors or inducers of CYP3A4, there is concern about DDIs with dexamethasone either as a perpetrator or a victim. Assessment of DDIs that involve dexamethasone is complex as dexamethasone is used at a range of daily doses (generally 0.5 up to 40 mg) and a treatment course can be short, long, or intermittent. Moreover, DDIs with dexamethasone have been evaluated only for a limited number of drugs. Here, we summarize the available in vitro and in vivo data on the interaction potential of dexamethasone and provide recommendations for the management of DDIs with ARVs, considering various dexamethasone dosages and treatment durations.

The intersection of drug interactions and adverse reactions in contemporary antiretroviral therapy

PURPOSE OF REVIEW

Advances in antiretroviral therapy (ART) have transformed HIV infection into a chronic and manageable condition. The introduction of potent and more tolerable antiretrovirals (ARVs) with favorable pharmacokinetic profiles has changed the prevalence and nature of drug-drug interactions (DDIs). Here, we review the relevance of DDIs in the era of contemporary ART.

RECENT FINDINGS

Management of DDIs remains an important challenge with modern ART, primarily due to increased polypharmacy in older persons living with HIV. Significant DDIs exist between boosted ARVs or older nonnucleoside reverse transcriptase inhibitors and comedications for chronic comorbidities (e.g., anticoagulants, antiplatelets, statins) or complex conditions (e.g., anticancer agents, immunosuppressants). Newer ARVs such as unboosted integrase inhibitors, doravirine, and fostemsavir have reduced DDI potential, but there are clinically relevant DDIs that warrant consideration. Potential consequences of DDIs include increased toxicity and/or reduced efficacy of ARVs and/or comedications. Management approaches include switching to an ARV with less DDI potential, changing comedications, or altering medication dosage or dosing frequency. Deprescribing strategies can reduce DDIs and polypharmacy, improve adherence, minimize unnecessary adverse effects, and prevent medication-related errors.

SUMMARY

Management of DDIs requires close interdisciplinary collaboration from multiple healthcare disciplines (medicine, nursing, pharmacy) across a spectrum of care (community, outpatient, inpatient).

Long-acting antiretrovirals: a new era for the management and prevention of HIV infection

The long-acting antiretroviral cabotegravir and rilpivirine combination has just received FDA, EMA and Health Canada approval. This novel drug delivery approach is about to revolutionize the therapy of people living with HIV, decreasing the 365 daily pill burden to only six intramuscular injections per year. In addition, islatravir, a first-in-class nucleoside reverse transcriptase translocation inhibitor, is intended to be formulated as an implant with a dosing interval of 1 year or more. At present, long-acting antiretroviral therapies (LA-ARTs) are given at fixed standard doses, irrespectively of the patient's weight and BMI, and without consideration for host genetic and non-genetic factors likely influencing their systemic disposition. Despite a few remaining challenges related to administration (e.g. pain, dedicated medical procedure), the development and implementation of LA-ARTs can overcome long-term adherence issues by improving patients' privacy and reducing social stigma associated with the daily oral intake of anti-HIV treatments. Yet, the current 'one-size-fits-all' approach does not account for the recognized significant inter-individual variability in LA-ART pharmacokinetics. Therapeutic drug monitoring (TDM), an important tool for precision medicine, may provide physicians with valuable information on actual drug exposure in patients, contributing to improve their management in real life. The present review aims to update the current state of knowledge on these novel promising LA-ARTs and discusses their implications, particularly from a clinical pharmacokinetics perspective, for the future management and prevention of HIV infection, issues of ongoing importance in the absence of curative treatment or an effective vaccine.