In Vitro Evaluation of the Drug Interaction Potential of Doravirine

Development and validation of equilibrium dialysis UHPLC-MS/MS measurement procedures for total and unbound concentrations of bictegravir, dolutegravir, darunavir and doravirine in human plasma. Application to patients with HIV

BACKGROUND

Fixed-dose combinations of antiretroviral drugs are commonly used to treat HIV infection and therapeutic monitoring is not part of routine clinical practice. However, drug concentrations monitoring might have role in different clinical scenarios as well as for research purposes. This study aimed to develop and validate UHPLC-MS/MS procedures for measuring total and unbound concentrations of bictegravir, dolutegravir, darunavir and doravirine in human plasma.

MATERIAL AND METHODS

Equilibrium dialysis preceded sample preparation (based on protein precipitation) for measuring unbound antiretroviral concentrations. Chromatographic separations were achieved on an Acquity®-UPLC® HSS™-T3 column (50 mm × 2.1 mm; 1.8 µm) using a non-linear water/acetonitrile gradient containing 0.1 % formic acid at a 0.5 mL/min flow rate. Antiretrovirals were detected by tandem mass spectrometry in positive electrospray ionisation and multiple reaction monitoring modes.

RESULTS

No significant interferences or carry-over were observed. Imprecisions, absolute relative biases, normalised matrix effects and recoveries were ≤15.0 %, ≤11.1 %, (94.7-104.1)% and (96.7-105.5)%, respectively. Non-linear measuring intervals were observed between (25-10,000) µg/L for total/plasma dialysate concentrations and linearity schemes (1.00-100) µg/L for buffer dialysate concentrations.

CONCLUSIONS

The UHPLC-MS/MS procedures developed could be used for research purposes and therapeutic drug monitoring of antiretrovirals in routine clinical practice.

Doravirine Exposure Decreased by Dialysis in a HIV Patient: A Grand Round

BACKGROUND

The authors report the case of a 66-year-old male patient who was hemodialyzed 3 times per week for chronic renal failure and treated with 100 mg of doravirine once daily in combination with dolutegravir for HIV-1. No dose adjustment is required for doravirine in cases of severe renal injury, but the effect of dialysis on its exposure is poorly understood.

METHODS RESULTS

Two series of 2 samples were drawn before and after 4-hour hemodialysis and showed an average doravirine concentration decrease of 48.1 ± 6.7%. The effects of hemodialysis were important, contrary to what was expected and has been previously reported. In addition, intraindividual variability was low. Nevertheless, because the concentrations reported were largely above the inhibitory concentration 50 (IC 50 ), no dose adjustment was required.

CONCLUSIONS

The decrease in doravirine concentration due to hemodialysis observed in this case report was quite significant. Therefore, therapeutic drug monitoring might be recommended in certain patients undergoing doravirine treatment also on hemodialysis.

Prediction of Maternal and Fetal Doravirine Exposure by Integrating Physiologically Based Pharmacokinetic Modeling and Human Placenta Perfusion Experiments

Background and Objective

Doravirine is currently not recommended for pregnant women living with human immunodeficiency virus because efficacy and safety data are lacking. This study aimed to predict maternal and fetal doravirine exposure by integrating human placenta perfusion experiments with pregnancy physiologically based pharmacokinetic (PBPK) modeling.

Methods

Ex vivo placenta perfusions were performed in a closed–closed configuration, in both maternal-to-fetal and fetal-to-maternal directions (n = 8). To derive intrinsic placental transfer parameters from perfusion data, we developed a mechanistic placenta model. Next, we developed a maternal and fetal full-body pregnancy PBPK model for doravirine in Simcyp, which was parameterized with the derived intrinsic placental transfer parameters to predict in vivo maternal and fetal doravirine exposure at 26, 32, and 40 weeks of pregnancy. The predicted total geometric mean (GM) trough plasma concentration (C_trough) values were compared with the target (0.23 mg/L) derived from in vivo exposure–response analysis.

Results

A decrease of 55% in maternal doravirine area under the plasma concentration–time curve (AUC)_0–24h was predicted in pregnant women at 40 weeks of pregnancy compared with nonpregnant women. At 26, 32, and 40 weeks of pregnancy, predicted maternal total doravirine GM C_trough values were below the predefined efficacy target of 0.23 mg/L. Perfusion experiments showed that doravirine extensively crossed the placenta, and PBPK modeling predicted considerable fetal doravirine exposure.

Conclusion

Substantially reduced maternal doravirine exposure was predicted during pregnancy, possibly resulting in impaired efficacy. Therapeutic drug and viral load monitoring are advised for pregnant women treated with doravirine. Considerable fetal doravirine exposure was predicted, highlighting the need for clinical fetal safety data.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-022-01127-0.

Approved HIV reverse transcriptase inhibitors in the past decade

HIV reverse transcriptase (RT) inhibitors are the important components of highly active antiretroviral therapies (HAARTs) for anti-HIV treatment and pre-exposure prophylaxis in clinical practice. Many RT inhibitors and their combination regimens have been approved in the past ten years, but a review on their drug discovery, pharmacology, and clinical efficacy is lacking. Here, we provide a comprehensive review of RT inhibitors (tenofovir alafenamide, rilpivirine, doravirine, dapivirine, azvudine and elsulfavirine) approved in the past decade, regarding their drug discovery, pharmacology, and clinical efficacy in randomized controlled trials. Novel RT inhibitors such as islatravir, MK-8504, MK-8507, MK8583, IQP-0528, and MIV-150 will be also highlighted. Future development may focus on the new generation of novel antiretroviral inhibitors with higher bioavailability, longer elimination half-life, more favorable side-effect profiles, fewer drug-drug interactions, and higher activities against circulating drug-resistant strains.

Predicting Solubility of Newly-Approved Drugs (2016–2020) with a Simple ABSOLV and GSE(Flexible-Acceptor) Consensus Model Outperforming Random Forest Regression

This study applies the ‘Flexible-Acceptor’ variant of the General Solubility Equation, GSE(Φ,B), to the prediction of the aqueous intrinsic solubility, log₁₀S₀, of FDA recently-approved (2016–2020) ‘small-molecule’ new molecular entities (NMEs). The novel equation had been shown to predict the solubility of drugs beyond Lipinski’s ‘Rule of 5’ chemical space (bRo5) to a precision nearly matching that of the Random Forest Regression (RFR) machine learning method. Since then, it was found that the GSE(Φ,B) appears to work well not only for bRo5 NMEs, but also for Ro5 drugs. To put context to GSE(Φ,B), Yalkowsky’s GSE(classic), Abraham’s ABSOLV, and Breiman’s RFR models were also applied to predict log₁₀ S₀ of 72 newly-approve NMEs, for which useable reported solubility values could be accessed (nearly 60% from FDA New Drug Application published reports). Except for GSE (classic), the prediction models were retrained with an enlarged version of the Wiki-pS₀ database (nearly 400 added log₁₀ S₀ entries since our recent previous study). Thus, these four models were further validated by the additional independent solubility measurements which the newly-approved drugs introduced. The prediction methods ranked RFR ~ GSE (Φ,B) > ABSOLV > GSE (classic) in performance. It was further demonstrated that the biases generated in the four separate models could be nearly eliminated in a consensus model based on the average of just two of the methods: GSE (Φ,B) and ABSOLV. The resulting consensus prediction equation is simple in form and can be easily incorporated into spreadsheet calculations. Even more significant, it slightly outperformed the RFR method.

Islatravir Is Not Expected to Be a Victim or Perpetrator of Drug-Drug Interactions via Major Drug-Metabolizing Enzymes or Transporters

Islatravir (MK-8591) is a nucleoside reverse transcriptase translocation inhibitor in development for the treatment and prevention of HIV-1. The potential for islatravir to interact with commonly co-prescribed medications was studied in vitro. Elimination of islatravir is expected to be balanced between adenosine deaminase-mediated metabolism and renal excretion. Islatravir did not inhibit uridine diphosphate glucuronosyltransferase 1A1 or cytochrome p450 (CYP) enzymes CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, or 3A4, nor did it induce CYP1A2, 2B6, or 3A4. Islatravir did not inhibit hepatic transporters organic anion transporting polypeptide (OATP) 1B1, OATP1B3, organic cation transporter (OCT) 1, bile salt export pump (BSEP), multidrug resistance-associated protein (MRP) 2, MRP3, or MRP4. Islatravir was neither a substrate nor a significant inhibitor of renal transporters organic anion transporter (OAT) 1, OAT3, OCT2, multidrug and toxin extrusion protein (MATE) 1, or MATE2K. Islatravir did not significantly inhibit P-glycoprotein and breast cancer resistance protein (BCRP); however, it was a substrate of BCRP, which is not expected to be of clinical significance. These findings suggest islatravir is unlikely to be the victim or perpetrator of drug-drug interactions with commonly co-prescribed medications, including statins, diuretics, anti-diabetic drugs, proton pump inhibitors, anticoagulants, benzodiazepines, and selective serotonin reuptake inhibitors.

NNRTI and Liver Damage: Evidence of Their Association and the Mechanisms Involved

Due to the improved effectiveness and safety of combined antiretroviral therapy, human immunodeficiency virus (HIV) infection has become a manageable, chronic condition rather than a mortal disease. However, HIV patients are at increased risk of experiencing non-AIDS-defining illnesses, with liver-related injury standing out as one of the leading causes of death among these patients. In addition to more HIV-specific processes, such as antiretroviral drug-related toxicity and direct injury to the liver by the virus itself, its pathogenesis is related to conditions that are also common in the general population, such as alcoholic and non-alcoholic fatty liver disease, viral hepatitis, and ageing. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are essential components of combined anti-HIV treatment due to their unique antiviral activity, high specificity, and acceptable toxicity. While first-generation NNRTIs (nevirapine and efavirenz) have been related largely to liver toxicity, those belonging to the second generation (etravirine, rilpivirine and doravirine) seem to be generally safe for the liver. Indeed, there is preclinical evidence of rilpivirine being hepatoprotective in different models of liver injury, independently of the presence of HIV. The present study aims to review the mechanisms by which currently available anti-HIV drugs belonging to the NNRTI family may participate in the development of liver disease.

A Phase 1 Study to Evaluate the Drug Interaction Between Islatravir (MK-8591) and Doravirine in Adults Without HIV

BACKGROUND AND OBJECTIVES

Islatravir (MK-8591) is a novel nucleoside analogue in development for the treatment and prevention of HIV-1 infection. Doravirine is a non-nucleoside reverse transcriptase inhibitor indicated for the treatment of HIV-1 infection. This study evaluated the pharmacokinetics, safety, and tolerability of islatravir and doravirine coadministration in a double-blind, placebo-controlled, randomized, fixed-sequence study.

METHODS

Adult participants without HIV infection were administered oral doravirine 100 mg (n = 10) or placebo (n = 4) once daily (QD) for 5 days, immediately followed by oral islatravir 2.25 mg (n = 10) or placebo QD (n = 4) for 14 days; islatravir 2.25 mg and doravirine 100 mg QD, or placebo QD, were then coadministered for 5 days. Pharmacokinetic and safety data were collected.

RESULTS

Doravirine geometric least-squares mean ratios (90% confidence intervals (CIs)) of (doravirine + islatravir)/doravirine for the area under the plasma drug concentration-time curve over 24 h (AUC0-24h), maximum plasma concentration (Cmax), and plasma concentration at 24 h post-dose (C24h) were not meaningfully impacted. Islatravir geometric least-squares mean ratios (90% CI) of (islatravir + doravirine)/islatravir for AUC0-24h and Cmax were both close to unity, 1.06 (1.01, 1.12) and 1.08 (0.91, 1.27), respectively. All study regimens were generally well tolerated.

CONCLUSION

These results indicate that coadministration of islatravir and doravirine had no clinically meaningful effect on the pharmacokinetics of either drug, and support further clinical investigation of islatravir in combination with doravirine for the treatment of HIV-1 infection.

Primary Care Guidance for Persons With Human Immunodeficiency Virus: 2020 Update by the HIV Medicine Association of the Infectious Diseases Society of America

Advances in antiretroviral therapy (ART) have made it possible for persons with human immunodeficiency virus (HIV) to live a near expected life span, without progressing to AIDS or transmitting HIV to sexual partners or infants. There is, therefore, increasing emphasis on maintaining health throughout the life span. To receive optimal medical care and achieve desired outcomes, persons with HIV must be consistently engaged in care and able to access uninterrupted treatment, including ART. Comprehensive evidence-based HIV primary care guidance is, therefore, more important than ever. Creating a patient-centered, stigma-free care environment is essential for care engagement. Barriers to care must be decreased at the societal, health system, clinic, and individual levels. As the population ages and noncommunicable diseases arise, providing comprehensive healthcare for persons with HIV becomes increasingly complex, including management of multiple comorbidities and the associated challenges of polypharmacy, while not neglecting HIV-related health concerns. Clinicians must address issues specific to persons of childbearing potential, including care during preconception and pregnancy, and to children, adolescents, and transgender and gender-diverse individuals. This guidance from an expert panel of the HIV Medicine Association of the Infectious Diseases Society of America updates previous 2013 primary care guidelines.

Clinical Pharmacokinetics of the Novel HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitor Doravirine: An Assessment of the Effect of Patient Characteristics and Drug-Drug Interactions

Doravirine (MK-1439) is a novel non-nucleoside reverse transcriptase inhibitor indicated for the combination treatment of human immunodeficiency virus type-1 (HIV-1) infection. The recommended dose is 100 mg once daily. This review summarizes the pharmacokinetics of doravirine, the influence of intrinsic factors, and its drug-drug interaction (DDI) profile. Following oral administration, doravirine is rapidly absorbed (median time to maximum plasma concentration, 1-4 h) and undergoes cytochrome P450 (CYP)3A-mediated oxidative metabolism. Steady-state geometric means for AUC0-24, C24, and Cmax in individuals with HIV-1 following administration of doravirine 100 mg once daily are 37.8 μM·h, 930 nM, and 2260 nM, respectively. Age, gender, severe renal impairment, and moderate hepatic impairment have no clinically meaningful effect on doravirine pharmacokinetics, and there is limited potential for DDIs. No dose adjustment is necessary when doravirine is co-administered with strong CYP3A inhibitors. However, doravirine is contraindicated with strong CYP3A inducers (e.g., rifampin), and dose adjustment of doravirine is recommended for co-administration with the moderate CYP3A inducer, rifabutin. Included in this review are clinical trial data from phase I pharmacokinetic trials, including DDI trials and trials in participants with renal and hepatic disease but without HIV-1 infection (N = 326), as well as phase I, II, and III safety and efficacy trials in participants living with HIV-1 (N = 991). Based on these data, the pharmacokinetic profile of doravirine supports its use in diverse populations living with HIV-1 and allows co-administration with various antiretroviral agents and treatments for commonly occurring co-morbidities.

Development of template systems for ligand interactions of CYP3A5 and CYP3A7 and their distinctions from CYP3A4 template

Starting from established CYP3A4 Template (DMPK. 2019, and 2020), CYP3A5 and CYP3A7 Templates have been constructed to be reliable tools for verification of their distinct catalytic properties. A distinct occupancy was observed on CYP3A4-selective ligands, but not on the non-selective ligands, in simulation experiments. These ligands often invade into Bay-1 region during the migration from Entrance to Site of oxidation in simulation experiments. These results offered an idea of the distinct localization of Bay-1 residue on CYP3A5 Template, in which the Bay-1 residue stayed closely to Template border. The idea also accounted for the higher oxidation rates of CYP3A5, than of CYP3A4, of noscapine and schisantherin E through their enhanced sitting-stabilization. Typical CYP3A7 substrates such as zonisamide and retinoic acids took their placements without occupying a left side region of Template for their metabolisms. In turn, the occupancies of the left-side region were inevitably observed among poor ligands of CYP3A7. Altered extent of IJK-Interaction or localization of a specific residue at the left-side would thus explain distinct catalytic properties of CYP3A7 on Template. These data suggest the alteration of each one of Template region, from CYP3A4 Template, led to the distinct catalytic properties of CYP3A5 and CYP3A7 forms.

Clinical Pharmacodynamics, Pharmacokinetics, and Drug Interaction Profile of Doravirine

Doravirine is a novel non-nucleoside reverse transcriptase inhibitor (NNRTI) that has demonstrated good efficacy, tolerability, and safety for the treatment of patients with human immunodeficiency virus (HIV)-1 infection in phase III clinical trials. Doravirine achieved non-inferiority when compared with efavirenz- and darunavir/ritonavir-based regimens. Fewer adverse effects, including neuropsychiatric effects were observed with doravirine compared with efavirenz. Key pharmacodynamic and pharmacokinetic characteristics as well as drug-drug interactions and the resistance profile were assessed in this clinical review. Doravirine is a pyridinone NNRTI with potent antiviral activity against wild-type HIV-1 virus and common NNRTI variants. Studies in healthy volunteers and HIV-infected individuals have shown that doravirine has a favorable pharmacokinetic profile for once-daily dosing, with an elimination half-life of around 15 h, median time to maximum plasma concentrations of 1-4 h, and time to steady-state concentration of 7 days. The pharmacokinetics of doravirine are not greatly influenced by sex, age, race, or hepatic impairment. Although no dose adjustment is required for doravirine in renal impairment when given as a single tablet, the fixed-dose combination tablet of doravirine/lamivudine/tenofovir disoproxil fumarate is not recommended in patients with a creatinine clearance of < 50 mL/min. Doravirine has a low potential for drug-drug interactions and does not impact on the pharmacokinetics of other drugs. However, it is metabolized via cytochrome P450 (CYP) 3A enzymes and is thus susceptible to interactions with CYP3A inhibitors and inducers. Strong CYP3A inhibitors can significantly increase doravirine exposure; however, this is not considered to be clinically relevant. Conversely, strong CYP3A inducers, such as rifampin, are contraindicated with doravirine owing to a significant reduction in exposure with potential for impaired virological efficacy. Moderate CYP3A inducers, such as rifabutin, may be co-administered if the doravirine dose is increased to 100 mg twice daily. Doravirine has a unique resistance profile and has demonstrated in vitro activity against some of the most common, clinically relevant NNRTI-resistant mutations. Prevalence of baseline NNRTI resistance to doravirine appears to be low in treatment-naïve cohorts. Further data on the efficacy of doravirine in patients with previous treatment experience and/or transmitted NNRTI resistance are required to further inform its place in the current armamentarium of drugs for the treatment of HIV infection.

HIV-1 Sanctuary Sites-the Role of Membrane-Associated Drug Transporters and Drug Metabolic Enzymes

Despite significant advances in the treatment of human immunodeficiency virus-1 (HIV) infection with highly active antiretroviral drug therapy, the persistence of the virus in cellular and anatomic reservoirs is a major obstacle preventing total HIV eradication. Viral persistence could result from a variety of contributing factors including, but not limited to, non-adherence to treatment and adverse drug reactions, latently infected cells carrying replication-competent virus, drug-drug interactions, and inadequate antiretroviral drug (ARV) concentrations reached in several anatomic sites such as the brain, testis, and gut-associated lymphoid tissues. The distribution of ARVs at specific sites of infection is primarily dependent on drug physicochemical properties and drug plasma protein binding, as well as drug efflux, influx, and metabolic processes. A thorough understanding of the functional roles of drug transporters and metabolic enzymes in the disposition of ARVs in immune cell types and tissues that are characterized as HIV reservoirs and sanctuaries is critical to overcome the challenge of suboptimal drug distribution at sites of persistent HIV infection. This review summarizes the current knowledge related to the expression and function of drug transporters and metabolic enzymes in HIV cellular and anatomic reservoirs, and their potential contribution to drug-drug interactions and insufficient drug concentration at these sites.

No meaningful drug interactions with doravirine, lamivudine and tenofovir disoproxil fumarate coadministration

BACKGROUND

Doravirine (DOR) is a novel non-nucleoside reverse transcriptase inhibitor available as a single tablet and a three-drug combination with lamivudine (3TC) and tenofovir disoproxil fumarate (TDF) to treat HIV-1 infection. These analyses assessed pharmacokinetic (PK) interactions with coadministration.

METHODS

Two trials were conducted. Study 1: two-period, fixed-sequence; eight healthy participants; Period 1, DOR 100 mg followed by ≥7-day washout; Period 2, TDF 300 mg once daily for 18 days, coadministration of DOR 100 mg on day 14. Study 2: three-period, crossover, 15 healthy participants; Treatment A, DOR 100 mg; Treatment B, 3TC 300 mg + TDF 300 mg; Treatment C, DOR 100 mg + 3TC 300 mg + TDF 300 mg; ≥7-day washout between periods.

RESULTS

Study 1: geometric mean ratios (GMRs; 90% confidence interval [CI]) of DOR area under the concentration-time curve from time 0 extrapolated to infinity (AUC_0-∞) and observed plasma concentrations at 24 h post-dose (C_{24 h}; DOR+TDF/DOR) were 0.95 (0.80, 1.12) and 0.94 (0.78, 1.12), respectively. Study 2: GMRs (90% CI) of DOR AUC_0-∞ and C_{24 h} (DOR+3TC+TDF/DOR) were 0.96 (0.87, 1.06) and 0.94 (0.83, 1.06), respectively. GMRs (90% CI) of 3TC and tenofovir AUC_0-∞ (DOR+3TC+TDF/3TC+TDF) were 0.94 (0.88, 1.00) and 1.11 (0.97, 1.28), respectively. Study drugs were generally well tolerated.

CONCLUSIONS

Multiple doses of TDF did not have a clinically meaningful effect on DOR PK. The PK of DOR were similar when administered alone or in combination with 3TC and TDF. DOR had no meaningful effect on the PK of 3TC and tenofovir.

Doravirine dose selection and 96-week safety and efficacy versus efavirenz in antiretroviral therapy-naive adults with HIV-1 infection in a Phase IIb trial

BACKGROUND

The safety and efficacy of doravirine were compared with that of efavirenz as initial treatment of adults living with HIV-1 infection (NCT01632345).

METHODS

A Phase IIb double-blind trial with participants stratified by screening HIV-1 RNA (≤ or >100,000 copies/ml) and randomized 1:1:1:1:1 to receive once-daily doravirine (25, 50, 100 or 200 mg) or efavirenz 600 mg (Part I) for up to 96 weeks, with open-label tenofovir disoproxil fumarate 300 mg/emtricitabine 200 mg (TDF/FTC). After dose selection at week 24, doravirine 100 mg was provided to participants receiving the other doses of doravirine and additional participants were randomized 1:1 to receive once-daily doravirine 100 mg or efavirenz 600 mg for 96 weeks with TDF/FTC (Part II). Primary outcomes were the proportion of participants with HIV-1 RNA <40 copies/ml at week 24, and central nervous system (CNS) adverse events (AEs) by weeks 8 and 24 (Parts I+II combined).

RESULTS

210 and 132 participants were randomized in Parts I and II, respectively, and 216 (108 on doravirine 100 mg, 108 on efavirenz) were evaluable for Parts I+II combined. At week 24, the proportion of participants with HIV-1 RNA <40 copies/ml was 72.9% for doravirine 100 mg and 73.1% for efavirenz (difference -0.5 [95% CI -12.3, 11.2]). In addition, CNS AEs were reported by 26.9% and 47.2% of doravirine and efavirenz recipients, respectively (difference -20.4 [95% CI -32.6, -7.5]; P=0.002).

CONCLUSIONS

Doravirine 100 mg with TDF/FTC demonstrated similar antiretroviral activity and superior CNS safety compared with efavirenz 600 mg with TDF/FTC.

Pharmacokinetics, safety and tolerability of long-acting parenteral intramuscular injection formulations of doravirine

WHAT IS KNOWN AND OBJECTIVE

Doravirine is a non-nucleoside reverse transcriptase inhibitor indicated for the treatment of human immunodeficiency virus (HIV)-1 infection. This phase 1 study in healthy adults investigated the pharmacokinetics, safety and tolerability of long-acting parenteral (LAP) microsuspension formulations of doravirine administered as an intramuscular (IM) injection.

METHODS

After confirmation of tolerability and safety of oral doravirine, 36 participants were randomized 1:1:1 to receive IM doravirine 200 mg as Treatment A (1 × 1 mL, 20% [200 mg/mL] suspension), B (1 × 0.66 mL, 30% [300 mg/mL] suspension) or C (2 × 0.5 mL, 20% suspension). Blood samples were taken as venous plasma, venous dried blood spots (DBS) and fingerstick DBS.

RESULTS AND DISCUSSION

Plasma concentration-time profiles following IM treatments demonstrated rapid initial doravirine release, with initial peak ~4 days post-injection, followed by decline over the next ~6 days; a second peak was reached at ~24-36 days, corresponding to prolonged and sustained release, with measurable concentrations up to Day 183. Treatment C was associated with highest peak concentrations and shortest time to maximum concentration. Elimination half-lives for all IM formulations were prolonged versus oral administration (~46-58 days vs ~11-15 hours). Oral doravirine and IM doravirine were generally well tolerated; injection-site pain was the most common adverse event for IM doravirine. Doravirine concentrations from DBS samples showed strong correlations to venous plasma concentrations.

WHAT IS NEW AND CONCLUSIONS

Novel doravirine LAP IM injection formulations investigated in this study demonstrated sustained plasma doravirine concentrations over a course of >20 weeks.

Pharmacokinetics of HIV therapies in pregnant patients: an update

INTRODUCTION

Mother-to-child transmission (MTCT) of HIV is thought to account for over 90% of new pediatric infections, and is associated with poor maternal and fetal outcomes. As such ensuring further reduction in MTCT is a priority in HIV treatment and prevention programs.

AREAS COVERED

This review aims to provide a comprehensive update on the pharmacokinetics of recently approved antiretroviral drugs and novel drug formulations and delivery systems. Alongside recent recommendations for dose adjustments, and an overview of the implications of co-infections on the pharmacokinetics of antiretrovirals relevant to pregnant HIV positive patients. Additionally, potential opportunities to progress pharmacokinetic research of new treatments in this population are highlighted.

EXPERT OPINION

In order to improve our understanding of how to provide safe and effective treatment to HIV positive pregnant women, further work is required to enable their inclusion in early stages of clinical trials. Incentives must be created for this research, in the form of additional investment by key stakeholders and regulatory agencies. Furthermore, as the incidence of MTCT is reduced globally there is a need to conduct long-term pharmacovigilance studies in uninfected children exposed to HIV and antiretrovirals in utero, in order to determine the safest and most effective antiretroviral therapies.

Comparative Bioavailability of Oral Granule Formulations of the HIV Antiretroviral Drugs Doravirine, Lamivudine, and Tenofovir Disoproxil Fumarate

Doravirine is a non-nucleoside reverse transcriptase inhibitor indicated for the treatment of human immunodeficiency virus-1 infection, available as a single tablet in combination with other antiretroviral agents or as a fixed-dose regimen with lamivudine and tenofovir disoproxil fumarate (TDF). Alternative formulations of these drugs are being developed for individuals who have difficulty swallowing tablets. Two phase 1 trials were conducted, both in 24 healthy adults, to assess the pharmacokinetics of uncoated and coated oral granule formulations of doravirine, lamivudine, and TDF administered alone and with vanilla pudding or apple sauce. The pharmacokinetics for all uncoated granules, and of coated lamivudine and TDF granules, were similar to those of currently marketed tablets (geometric mean ratios [GMRs] 0.92-1.04). Coated doravirine granules had decreased AUC_0-∞ (11%) and C_max (23%) values versus the tablet. The pharmacokinetics were similar for uncoated and coated doravirine granules administered with or without pudding (GMRs 0.96-1.10); administration with apple sauce increased doravirine AUC_0-∞ (26-29%), C_max (56-59%), and C₂₄ (20-21%) versus administration of granules alone. Lamivudine granules administered with pudding or apple sauce decreased AUC_0-∞ and C_max (14-25%) versus granules alone. Tenofovir AUC_0-∞, C_max, and C₂₄ increased for TDF granules administered with pudding or apple sauce versus alone (11-23%). Pharmacokinetic differences when administering doravirine, lamivudine, or TDF as uncoated or coated granules versus tablets, or when granules were administered with (versus without) pudding or apple sauce, are not considered clinically meaningful, supporting further development of these granule formulations.

Evaluation of the Pharmacokinetic Interaction Between Doravirine and Methadone

Doravirine is a novel nonnucleoside reverse transcriptase inhibitor indicated for the treatment of HIV type 1 infection. A subset of people living with HIV receives methadone for the treatment of opioid addiction. The current study (NCT02715700) was an open-label, multiple-dose, drug interaction study in participants on a methadone maintenance program to investigate potential drug-drug interactions between doravirine and methadone. Participants received a stable methadone maintenance dose of 20 to 180 mg once daily for 14 days prior to day 1 and remained on their maintenance dose over days 1 through 7. On days 2 through 6, an oral dose of doravirine 100 mg was coadministered. For doravirine and methadone pharmacokinetic analysis, blood samples were collected before dosing through 24 hours after dosing. Fourteen participants were enrolled; all participants completed the study. For R-methadone, geometric least squares mean ratios (90% confidence intervals) for dose-normalized area under the plasma concentration-time curve from time zero to 24 hours, plasma concentration at 24 hours, and maximum plasma concentration ([methadone + doravirine]/methadone alone) were 0.95 (0.90-1.01), 0.95 (0.88-1.03), and 0.98 (0.93-1.03), respectively. For doravirine, based on a comparison with historical data, modest decreases in area under the plasma concentration-time curve from time zero to 24 hours, plasma concentration at 24 hours, and maximum plasma concentration were observed after coadministration of doravirine and methadone; geometric least squares mean ratios ([methadone + doravirine]/doravirine alone [90% confidence intervals]) were 0.74 (0.61-0.90), 0.80 (0.63-1.03), and 0.76 (0.63-0.91), respectively. Coadministration of doravirine and methadone was generally well tolerated. No serious adverse events occurred, and there were no discontinuations. In conclusion, coadministration of methadone and doravirine did not have a clinically meaningful effect on the pharmacokinetic profile of either agent.

Doravirine and the Potential for CYP3A-Mediated Drug-Drug Interactions

Identifying and understanding potential drug-drug interactions (DDIs) are vital for the treatment of human immunodeficiency virus type 1 (HIV-1) infection. This article discusses DDIs between doravirine, a nonnucleoside reverse transcriptase inhibitor (NNRTI), and cytochrome P450 3A (CYP3A) substrates and drugs that modulate CYP3A activity. Consistent with previously published in vitro data and DDI trials with the CYP3A substrates midazolam and atorvastatin, doravirine did not have any meaningful impact on the pharmacokinetics of the CYP3A substrates ethinyl estradiol and levonorgestrel. Coadministration of doravirine with CYP3A inhibitors (ritonavir or ketoconazole) increased doravirine exposure approximately 3-fold. However, these increases were not considered clinically meaningful. Conversely, previously published trials showed that coadministered CYP3A inducers (rifampin and rifabutin) decreased doravirine exposure by 88% and 50%, respectively (K. L. Yee, S. G. Khalilieh, R. I. Sanchez, R. Liu, et al., Clin Drug Investig 37:659-667, 2017 [https://doi.org/10.1007/s40261-017-0513-4]; S. G. Khalilieh, K. L. Yee, R. I. Sanchez, R. Liu, et al., J Clin Pharmacol 58:1044-1052, 2018 [https://doi.org/10.1002/jcph.1103]), while doravirine exposure following prior efavirenz administration led to an initial reduction in doravirine exposure of 62%, but the reduction became less pronounced with time (K. L. Yee, R. I. Sanchez, P. Auger, R. Liu, et al., Antimicrob Agents Chemother 61:e01757-16, 2017 [https://doi.org/10.1128/AAC.01757-16]). Overall, the coadministration of doravirine with CYP3A inhibitors and substrates is, therefore, supported by these data together with efficacy and safety data from clinical trials, while coadministration with strong CYP3A inducers, such as rifampin, cannot be recommended. Concomitant dosing with rifabutin (a CYP3A inducer less potent than rifampin) is acceptable if doravirine dosing is adjusted from once to twice daily; however, the effect of other moderate inducers on doravirine pharmacokinetics is unknown.

Investigation of Pharmacokinetic Interactions between Doravirine and Elbasvir-Grazoprevir and Ledipasvir-Sofosbuvir

Doravirine is a non-nucleoside reverse transcriptase inhibitor for the treatment of human immunodeficiency virus type 1 (HIV-1) infection. Due to the high prevalence of HIV-1 and hepatitis C virus (HCV) coinfection and coadministration of HIV-1 and HCV treatment, potential drug-drug interactions (DDIs) between doravirine and two HCV treatments were investigated in two phase 1 drug interaction trials in healthy participants. Trial 1 investigated the effect of multiple-dose doravirine and elbasvir + grazoprevir coadministration (N = 12), and trial 2 investigated the effect of single-dose doravirine and ledipasvir-sofosbuvir coadministration (N = 14). Doravirine had no clinically relevant effect on the pharmacokinetics of elbasvir, grazoprevir, ledipasvir, sofosbuvir, or the sofosbuvir metabolite GS-331007. Coadministration of elbasvir + grazoprevir with doravirine moderately increased doravirine area under the concentration-time curve from 0 to 24 h (AUC_0-24), maximal concentration (C _max), and concentration 24 h postdose (C ₂₄), with geometric least-squares mean ratio (GMR) with 90% confidence intervals (CI) of 1.56 (1.45, 1.68), 1.41 (1.25, 1.58), and 1.61 (1.45, 1.79), respectively. Doravirine AUC_0-∞, C _max, and C ₂₄ values increased slightly following coadministration with ledipasvir-sofosbuvir (GMR [90% CI] of 1.15 [1.07, 1.24], 1.11 [0.97, 1.27], and 1.24 [1.13, 1.36], respectively). The modest increases in doravirine exposure are not clinically meaningful based on the therapeutic profile of doravirine. Effects are likely secondary to cytochrome P450 3A and P-glycoprotein inhibition by grazoprevir and ledipasvir, respectively. Coadministration of doravirine with elbasvir + grazoprevir or ledipasvir-sofosbuvir was generally well tolerated. Clinically relevant DDIs are not expected to occur between doravirine and elbasvir-grazoprevir or ledipasvir-sofosbuvir at the therapeutic doses.