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

Drug-Drug Interactions between Antiretrovirals and Hormonal Contraception: An Updated Systematic Review

OBJECTIVE

To summarize and update information regarding drug-drug interactions (DDIs) between antiretrovirals (ARVs) and hormonal contraceptives (HCs).

DESIGN

Systematic review METHODS: We searched seven databases for peer-reviewed publications from January 1, 2015, through December 31, 2023, including studies of women using ARVs and HCs concurrently with outcomes including therapeutic effectiveness or toxicity, pharmacokinetics (PK), or pharmacodynamics. We summarized findings and used checklists to assess evidence quality.

RESULTS

We included 49 articles, with clinical, ARV or HC PK outcomes reported by 39, 25, and 30 articles, respectively, with some articles reporting outcomes in two or more categories. Fifteen of 18 articles assessing DDIs between efavirenz and progestin implants, emergency contraception, or combined hormonal intravaginal rings found higher pregnancy rates, luteal progesterone levels suggesting ovulation, or reduced progestin PK values. Five studies documented that CYP2B6 single nucleotide polymorphisms exacerbated this DDI. One cohort detected doubled bone density loss with concomitant depot medroxyprogesterone acetate (DMPA) and tenofovir disoproxil fumarate (TDF)-containing ART use versus TDF alone. No other studies described DDIs impacting clinical outcomes. Few adverse events were attributed to ARV-HC use with none exceeding Grade 2. Evidence quality was generally moderate, with dis-similar treatment and control groups, identifying and controlling for confounding, and minimizing attrition bias in the study design being the most frequent limitations.

CONCLUSION

Most ARVs and HCs may be used safely and effectively together. TDF-DMPA DDIs warrant longer-term study on bone health and consideration of alternate combinations. For efavirenz-based ART, client counselling on relative risks, including both potential increase in pregnancy rate with concomitant efavirenz and implant use and lower pregnancy rates compared to other HCs even with concomitant efavirenz use, should continue to allow users comprehensive method choice.

Evaluation of plasma doravirine concentrations in patients with HIV-1 undergoing hemodialysis

The pharmacokinetics of doravirine (DOR) have not been clarified in patients undergoing hemodialysis (HD). In this study, we evaluated the pharmacokinetics of DOR in four HIV-1-infected patients undergoing HD who were administered DOR. The participants were patients undergoing HD for end-stage renal disease and were administered DOR. DOR was administered once daily (one tablet of 100 mg), every evening. On days of HD treatment, DOR was administered after the end of the procedure. After administration of DOR for at least 1 week, the plasma DOR concentration was measured. The median plasma trough DOR concentration was 766.9 ng/mL (range: 509-1085 ng/mL). The median DOR clearance by HD, DOR elimination rate, half-life (T_1/2) of plasma DOR concentration during HD, and T_1/2 during the non-HD period were 85.04 mL/min, 73.12%, 7.71 h, and 13.76 h, respectively. The T_1/2 during the HD period was significantly shorter than the T_1/2 during the non-HD period (p = 0.0030). In this study, elimination of DOR by HD was confirmed. Viral suppression was maintained in all patients undergoing HD, and none had adverse events or safety problems. As DOR is eliminated by HD, monitoring its plasma concentration is considered necessary for clinical use.

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.

Doravirine: its role in HIV treatment

PURPOSE OF REVIEW

We reviewed evidence concerning the novel nonnucleoside reverse transcriptase inhibitor doravirine, aiming to identify situations where it may be selected in preference to integrase inhibitors.

RECENT FINDINGS

Doravirine is licenced for the treatment of HIV-1 in North America and Europe. In two multicentre randomized controlled trials, noninferiority with comparator drugs efavirenz and darunavir/ritonavir was observed at 96 weeks. Doravirine is associated with a lower incidence of neuropsychiatric side effects relative to efavirenz, and favourable lipid changes relative to darunavir over 96 weeks. A lower incidence of weight gain, relative to indirect comparisons with integrase inhibitors, was observed. Doravirine has a high genetic barrier to resistance with retained activity in the presence of single NNRTI mutations K103N, Y181C and G190A. Primary drug resistance is infrequent and may be higher in South Africa relative to European populations. Doravirine may be used in renal or hepatic impairment and has a low potential for drug-drug interactions.

SUMMARY

Doravirine is a well tolerated and effective agent in ART-naive patients. Direct comparison with integrase inhibitors, and evidence on the outcomes of treatment with doravirine in the presence of prior NNRTI experience are required to better elucidate which patients will benefit most from doravirine therapy.

A phase 1, open-label study to evaluate the drug interaction between islatravir (MK-8591) and the oral contraceptive levonorgestrel/ethinyl estradiol in healthy adult females

Introduction

Hormonal contraceptives are among the most effective forms of reversible contraception, but many other compounds, including some antiretrovirals, have clinically meaningful drug–drug interactions (DDIs) with hormonal contraceptives. Islatravir is a novel human immunodeficiency virus nucleoside reverse transcriptase translocation inhibitor currently in clinical development for treatment and prevention of HIV infection. A phase 1 clinical trial was conducted to evaluate the DDI of islatravir and the combination of oral contraceptive levonorgestrel (LNG)/ethinyl estradiol (EE).

Methods

This was an open‐label, two‐period, fixed‐sequence, DDI clinical trial in healthy, postmenopausal or bilaterally oophorectomized females aged 18 through 65 years in the United States between October 2016 and January 2017. A single dose of LNG 0.15 mg/EE 0.03 mg was given followed by a 7‐day washout. Islatravir, 20 mg, was then dosed once weekly for 3 weeks; a single dose of LNG 0.15 mg/EE 0.03 mg was given concomitantly with the third dose of islatravir. Pharmacokinetic samples for plasma LNG and EE concentrations were collected pre‐dose and up to 120 hours post‐dose in each period. Safety and tolerability were assessed throughout the trial by clinical assessments, laboratory evaluations and examination of adverse events.

Results and Discussion

Fourteen participants were enrolled. The pharmacokinetics of LNG and EE were not meaningfully altered by co‐administration with islatravir. For the comparison of (islatravir + LNG/EE)/(LNG/EE alone), the geometric mean ratios (GMRs) (90% confidence intervals [CIs]) for LNG AUC_0–inf and C_max were 1.13 (1.06, 1.20) and 0.965 (0.881, 1.06), respectively. For EE, the GMRs (90% CI) for AUC_0–inf and C_max were 1.05 (0.981, 1.11) and 1.02 (0.971, 1.08), respectively. Co‐administration of all three drugs was generally well tolerated.

Conclusions

The results of this trial support the use of LNG/EE contraceptives in combination with islatravir without dose adjustment.

Pharmacokinetic interactions of modern antiretroviral therapy

Drug--drug interactions (DDIs) have been a clinical challenge in HIV medicine for over two decades. The newer antiretroviral drugs (ARTs) have significantly fewer DDIs than protease inhibitors and boosted integrase inhibitors (INSTIs). The lower propensity of such newer antiretrovirals (e.g. unboosted integrase inhibitors; doravirine) to cause DDIs, has been largely offset by the ageing cohort of patients with multiple comorbidities, who are taking multiple chronic medicines. Furthermore, the introduction of newly marketed drugs into clinical practice needs to be closely monitored, as the new drugs may be perpetrators of DDIs, leading to a potential change in the efficacy or toxicity of the coadministered antiretrovirals.

Antiretroviral Treatment and Antihypertensive Therapy

The presence of hypertension among the population with human immunodeficiency virus (HIV) has become a new threat to the health and well-being of people living with this disease, in particular, among those who received antiretroviral therapy. The estimated prevalence of high blood pressure in HIV-infected patients is significantly higher than the rate observed in HIV-uninfected subjects. The approach to the HIV-positive patient requires the assessment of individual cardiovascular risk and its consideration when designing the individualized target. On the other hand, the numerous pharmacological interactions of antiretroviral (ARV) drugs are essential elements to take into account. Serum levels of any kind of antihypertensive drugs may be influenced by the coadministration of protease inhibitors, non-nucleoside reverse transcriptase inhibitor, or other antiretroviral. Similarly, plasma concentrations of antiretroviral drugs can be increased by the concomitant use of calcium channel blockers or diuretics. In this regard, the treatment of high blood pressure in HIV patients should be preferentially based on ACE inhibitors or thiazide/thiazide-like diuretics or their combination.

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.

Insights into oral bioavailability enhancement of therapeutic herbal constituents by cytochrome P450 3A inhibition

Herbal plants typically have complex compositions and diverse mechanisms. Among them, bioactive constituents with relatively high exposure in vivo are likely to exhibit therapeutic efficacy. On the other hand, their bioavailability may be influenced by the synergistic effects of different bioactive components. Cytochrome P450 3A (CYP3A) is one of the most abundant CYP enzymes, responsible for the metabolism of 50% of approved drugs. In recent years, many therapeutic herbal constituents have been identified as CYP3A substrates. It is more evident that CYP3A inhibition derived from the herbal formula plays a critical role in improving the oral bioavailability of therapeutic constituents. CYP3A inhibition may be the mechanism of the synergism of herbal formula. In this review, we explored the multiplicity of CYP3A, summarized herbal monomers with CYP3A inhibitory effects, and evaluated herb-mediated CYP3A inhibition, thereby providing new insights into the mechanisms of CYP3A inhibition-mediated oral herb bioavailability.

Novel 1,2,3-Triazole Derivatives as Potential Inhibitors against Covid-19 Main Protease: Synthesis, Characterization, Molecular Docking and DFT Studies

The highly contagious nature of Covid-19 attracted us to this challenging area of research, mainly because the disease is spreading very fast and until now, no effective method of a safe treatment or a vaccine is developed. A library of novel 1,2,3-triazoles based 1,2,4-triazole, 1,3,4-oxadiazole and/or 1,3,4-thiadiazole scaffolds were designed and successfully synthesized. Different spectroscopic tools efficiently characterized all the newly synthesized hybrid molecules. An interesting finding is that some of the newly designed compounds revealed two isomeric forms. The ratio is affected by the size of the attached group as well as the type of the heteroatom forming the side ring attached to the central 1,2,3-triazole ring. The experimental spectroscopic data is in agreement with the DFT calculations at B3LYP 6-31G (d,p) with regard to the geometrical conformation of the prepared compounds. The DFT results revealed that the stability of one isomeric form over the other in the range of 0.057-0.161 Kcal mol-1. A docking study was performed using PyRx and AutoDockVina to investigate the activity of the prepared 1,2,3-triazoles as antiviral agents. Bond affinity scores of the 1,2,3-triazole derivatives were detected in the range of -6.0 to -8.8 kcal/mol showing binding to the active sites of the 6LU7 protease and hence could be anticipated to inhibit the activity of the enzyme. Verification of the docking results was performed using the Mpro alignment of coronaviruses substrate-binding pockets of COVID-19 against the ligands. As per these results, it can be proposed that the title hybrid molecules are acceptable candidates against COVID-19 for possible medicinal agents.

Inhibition and induction of CYP enzymes in humans: an update

The cytochrome P450 (CYP) enzyme family is the most important enzyme system catalyzing the phase 1 metabolism of pharmaceuticals and other xenobiotics such as herbal remedies and toxic compounds in the environment. The inhibition and induction of CYPs are major mechanisms causing pharmacokinetic drug–drug interactions. This review presents a comprehensive update on the inhibitors and inducers of the specific CYP enzymes in humans. The focus is on the more recent human in vitro and in vivo findings since the publication of our previous review on this topic in 2008. In addition to the general presentation of inhibitory drugs and inducers of human CYP enzymes by drugs, herbal remedies, and toxic compounds, an in-depth view on tyrosine-kinase inhibitors and antiretroviral HIV medications as victims and perpetrators of drug–drug interactions is provided as examples of the current trends in the field. Also, a concise overview of the mechanisms of CYP induction is presented to aid the understanding of the induction phenomena.

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.

Physiologically Based Pharmacokinetic Modeling of Doravirine and Its Major Metabolite to Support Dose Adjustment With Rifabutin

Doravirine, a novel nonnucleoside reverse transcriptase inhibitor for the treatment of human immunodeficiency virus 1 (HIV-1), is predominantly cleared by cytochrome P450 (CYP) 3A4 and metabolized to an oxidative metabolite (M9). Coadministration with rifabutin, a moderate CYP3A4 inducer, decreased doravirine exposure. Based on nonparametric superposition modeling, a doravirine dose adjustment from 100 mg once daily to 100 mg twice daily during rifabutin coadministration was proposed. However, M9 exposure may also be impacted by induction, in addition to the dose adjustment. As M9 concentrations have not been quantified in previous clinical studies, a physiologically based pharmacokinetic model was developed to investigate the change in M9 exposure when doravirine is coadministered with CYP3A inducers. Simulations demonstrated that although CYP3A induction increases doravirine clearance by up to 4.4-fold, M9 exposure is increased by only 1.2-fold relative to exposures for doravirine 100 mg once daily in the absence of CYP3A induction. Thus, a 2.4-fold increase in M9 exposure relative to the clinical dose of doravirine is anticipated when doravirine 100 mg twice daily is coadministered with rifabutin. In a subsequent clinical trial, doravirine and M9 exposures, when doravirine 100 mg twice daily was coadministered with rifabutin, were found to be consistent with model predictions using rifampin and efavirenz as representative inducers. These findings support the dose adjustment to doravirine 100 mg twice daily when coadministered with rifabutin.

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.

Haemopoietic cell transplantation in patients living with HIV

Haemopoietic cell transplantation is established as a standard treatment approach for people living with HIV who have haematological malignancies with poor prognosis. Studies with autologous and allogeneic haemopoietic cell transplantation suggest that HIV status does not adversely affect outcomes, provided that there is adequate infection prophylaxis. Attention to possible drug-drug interactions is important. Allogeneic haemopoietic cell transplantation substantially reduces the long-term HIV reservoir when complete donor chimerism is established. When transplants from CCR5Δ32 homozygous donors are used, HIV cure is possible.

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.

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.

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.