A Randomized Trial to Assess the Effect of Doravirine on the QTc Interval Using a Single Supratherapeutic Dose in Healthy Adult Volunteers

Thorough QT/QTc study to evaluate the effect of a single supratherapeutic dose of islatravir on QTc interval prolongation in healthy adults

Islatravir is a deoxynucleoside analog being developed for the treatment of HIV-1 infection. Clinical studies are being conducted to evaluate islatravir, administered in combination with other antiretroviral therapies, at doses of 0.25 mg once daily and 2 mg once weekly. In multiple previous clinical studies, islatravir was generally well tolerated, with no clear trend in cardiac adverse events. A trial was conducted to evaluate the effect of islatravir on cardiac repolarization. A randomized, double-blind, active- and placebo-controlled phase 1 trial was conducted, in which a single dose of islatravir 0.75 mg, islatravir 240 mg (supratherapeutic dose), moxifloxacin 400 mg (active control), or placebo was administered. Continuous 12-lead electrocardiogram monitoring was performed before dosing through 24 hours after dosing. QT interval measurements were collected, and safety and pharmacokinetics were evaluated. Sixty-three participants were enrolled, and 59 completed the study. Fridericia's QT correction for heart rate was inadequate; therefore, a population-specific correction was applied (QTcP). The placebo-corrected change from baseline in QTcP (ΔΔQTcP) interval at the observed geometric mean maximum plasma concentration associated with islatravir 0.75 mg and islatravir 240 mg was <10 ms at all time points. Assay sensitivity was confirmed because the use of moxifloxacin 400 mg led to a ΔΔQTcP >10 ms. The pharmacokinetic profile of islatravir was consistent with that of previous studies, and islatravir was generally well tolerated. Results from the current trial suggest that single doses of islatravir as high as 240 mg do not lead to QTc interval prolongation.

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.

Comparative safety review of recommended, first-line single-tablet regimens in patients with HIV

Introduction Different single-tablet regimens (STRs), containing one or two nucleoside reverse transcriptase inhibitors (NRTIs) plus an anchor drug, are available for the use in naïve, HIV-infected patients. Despite some restrictions in the use of particular regimens in certain situations (e.g., HBV coinfection), International guidelines do not provide indications to prefer any regimen over others concerning the tolerability profile. We aimed to assess advantages and disadvantages of the most prescribed STRs.Areas covered An extensive review of articles published in English language was conducted on PubMed, looking for evidence about STRs in naïve, HIV-infected population. Safety outcomes of registrational trials were assessed, giving priority to studies directly comparing STRs included in our research (abacavir/lamivudine/dolutegravir, tenofovir alafenamide/emtricitabine/bictegravir, lamivudine/dolutegravir, tenofovir alafenamide/emtricitabine/darunavir/cobicistat, tenovofir disoproxil fumarate/lamivudine/doravirine). Data from cohort studies and meta-analyses were also assessed, extrapolating the main evidence about the combinations of interest.Expert opinion Integrase inhibitors (InsTIs)-based regimens have few interruptions for adverse events and few drug-related adverse events, with tenofovir alafenamide/emtricitabine/dolutegravir and lamivudine/dolutegravir being the most tolerable ones. However, neuropsychiatric adverse events and metabolic issues could prompt the alternative use of darunavir or doravirine-based combinations, even if a superior safety profile of these combinations over InSTIs has yet to be demonstrated.

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.

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.

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.

Rational Design of Doravirine: From Bench to Patients

Since the approval of nevirapine, the first HIV-1 non-nucleoside reverse transcriptase inhibitor (NNRTI) in 1996, NNRTIs have helped play a critical role in maintaining viral suppression in people living with HIV. The many positive attributes of the class, including potency and long plasma half-life, make them attractive drug discovery targets. Given the availability of multiple once-daily integrase-based treatments for HIV-1 infection, the challenge to develop a new antiretroviral agent that addresses the needs of today's patients is formidable. However, with the increased availability of antiretrovirals for treatment and new pre-exposure prophylaxis guidelines, which should globally expand the use of antiretrovirals in prevention, it will be increasingly important to have access to multiple regimens with options from different classes that are well tolerated and convenient to ensure a sustained impact on the global epidemic. Many attempts to improve upon the NNRTI class have failed to deliver a desirable clinical profile consistent with the current landscape of treatment options. Doravirine is the only NNRTI to successfully advance through phase 3 clinical development and approval in recent years. Learning from the liabilities of approved NNRTIs, as well as past development failures, facilitated a rational approach to the discovery of doravirine by focusing on addressing the known safety/tolerability issues of commonly prescribed NNRTIs, such as central nervous system toxicity with efavirenz and potential cardiotoxicity due to off-target effects on cardiac ion channels with rilpivirine, using structural biology and characterization of resistance in vitro to address resistance liabilities and concentrating on the metabolic profile to limit the potential for drug-drug interactions. These preclinical efforts were critical to the design and selection of doravirine as a novel NNRTI that possessed the desired next-generation profile with the ultimate proof that these attributes translate to patients derived from clinical trials.

Doravirine: First Global Approval

Doravirine is a new non-nucleoside reverse transcriptase inhibitor (NNRTI) developed by Merck & Co for the treatment of HIV-1 infection. The drug is approved in the USA both as a single-agent tablet (Pifeltro™) and as a fixed-dose combination tablet with the nucleos(t)ide reverse transcriptase inhibitors lamivudine and tenofovir disoproxil fumarate (Delstrigo™). Each formulation is indicated in the USA for treating HIV-1 infection in adults with no prior antiretroviral treatment, has received a positive opinion in the EU for treating HIV-1 infection in adults without resistance to NNRTIs or (in the case of the fixed-dose combination tablet) lamivudine or tenofovir, and is also under regulatory review for the treatment of HIV-1 infection in Canada. This article summarizes the milestones in the development of doravirine leading to this first approval for the treatment of HIV-1 infection in treatment-naïve adults.

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.

Doravirine: a review

PURPOSE OF REVIEW

The current review addresses the role of doravirine (DOR), a novel once-daily nonnucleoside reverse transcriptase inhibitor (NNRTI) in first-line therapy at a time in which multiple options are available, and issues of antiviral efficacy, safety, simplicity and cost are critical to make informed decisions.

RECENT FINDINGS

DOR combination regimens have been tested in two large randomized double-blinded clinical trials in treatment-naïve patients, showing noninferiority to ritonavir-boosted darunavir-based and efavirenz (EFV)-based regimens. The main features of DOR are reviewed in this report including its antiviral activity, genetic barrier to resistance, safety, once-daily dosing and coformulation in a single tablet with tenofovir disoproxil fumarate and lamivudine. DOR pharmacokinetics and drug-drug interactions are also reviewed as DOR can be given without food restriction and has no interaction with proton pump inhibitors. DOR has shown a superior safety profile than EFV regarding neuropsychiatric and cutaneous adverse events. DOR is currently being investigated in treatment-experienced patients and in those with transmitted NNRTI drug resistance.

SUMMARY

DOR is a promising new NNRTI that could become the preferred drug in its class for treatment initiation. DOR has shown excellent antiviral activity in treatment-naïve patients, a better safety profile than EFV and a low potential for drug-drug interactions.