Clinical improvement in psoriasis with specific targeting of interleukin-23.

Psoriasis is a chronic inflammatory skin disorder that affects approximately 2-3% of the population worldwide and has severe effects on patients' physical and psychological well-being. The discovery that psoriasis is an immune-mediated disease has led to more targeted, effective therapies; recent advances have focused on the interleukin (IL)-12/23p40 subunit shared by IL-12 and IL-23. Evidence suggests that specific inhibition of IL-23 would result in improvement in psoriasis. Here we evaluate tildrakizumab, a monoclonal antibody that targets the IL-23p19 subunit, in a three-part, randomized, placebo-controlled, sequential, rising multiple-dose phase I study in patients with moderate-to-severe psoriasis to provide clinical proof that specific targeting of IL-23p19 results in symptomatic improvement of disease severity in human subjects. A 75% reduction in the psoriasis area and severity index (PASI) score (PASI75) was achieved by all subjects in parts 1 and 3 (pooled) in the 3 and 10 mg kg(-1) groups by day 196. In part 2, 10 out of 15 subjects in the 3 mg kg(-1) group and 13 out of 14 subjects in the 10 mg kg(-1) group achieved a PASI75 by day 112. Tildrakizumab demonstrated important clinical improvement in moderate-to-severe psoriasis patients as demonstrated by improvements in PASI scores and histological samples.

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.

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 AUC0-∞ (11%) and Cmax (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 AUC0-∞ (26-29%), Cmax (56-59%), and C24 (20-21%) versus administration of granules alone. Lamivudine granules administered with pudding or apple sauce decreased AUC0-∞ and Cmax (14-25%) versus granules alone. Tenofovir AUC0-∞, Cmax, 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.

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 (AUC0-24), maximal concentration (Cmax), and concentration 24 h postdose (C24), 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 AUC0-∞, Cmax, and C24 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.

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.

Characterisation of the absorption, distribution, metabolism, excretion and mass balance of doravirine, a non-nucleoside reverse transcriptase inhibitor in humans.

Absorption, distribution, metabolism and elimination of doravirine (MK-1439), a novel non-nucleoside reverse transcriptase inhibitor, were investigated. Two clinical trials were conducted in healthy subjects: an oral single dose [14 C]doravirine (350 mg, ∼200 µCi) trial (n = 6) and an intravenous (IV) single-dose doravirine (100 µg) trial (n = 12). In vitro metabolism, protein binding, apparent permeability and P-glycoprotein (P-gp) transport studies were conducted to complement the clinical trials. Following oral [14 C]doravirine administration, all of the administered dose was recovered. The absorbed dose was eliminated primarily via metabolism. An oxidative metabolite (M9) was the predominant metabolite in excreta and was the primary circulating metabolite (12.9% of circulating radioactivity). Following IV administration, doravirine clearance and volume of distribution were 3.73 L/h (95% confidence intervals (CI) 3.09, 4.49) and 60.5 L (95% CI 53.7, 68.4), respectively. In vitro, doravirine is not highly bound to plasma proteins (unbound fraction 0.24) and has good passive permeability. The metabolite M9 was generated by cytochrome P450 3A (CYP3A)4/5-mediated oxidation. Doravirine was a P-gp substrate but P-gp efflux is not expected to play a significant role in limiting doravirine absorption or to be involved in the elimination of doravirine. In conclusion, doravirine is a low clearance drug, primarily eliminated by CYP3A-mediated metabolism.

Severe Renal Impairment Has Minimal Impact on Doravirine Pharmacokinetics.

Doravirine is a novel nonnucleoside reverse transcriptase inhibitor in development for use with other antiretroviral therapies to treat human immunodeficiency virus type 1 (HIV-1) infection. Doravirine metabolism predominantly occurs via cytochrome P450 3A with <10% of elimination occurring via the renal pathway. As severe renal impairment can alter the pharmacokinetics (PK) of metabolically eliminated drugs, the effect of severe renal impairment on doravirine PK was assessed. A single dose of doravirine 100 mg was administered to subjects aged 18 to 75 years with an estimated glomerular filtration rate (eGFR) of <30 ml/min/1.73 m2 (severe renal impairment group) and healthy controls with an eGFR of ≥80 ml/min/1.73 m2, matched to the mean of the renal impairment group by age (±10 years) and weight (±10 kg). Doravirine plasma concentrations were determined at regular intervals, and safety was monitored throughout. The geometric mean ratios (90% confidence interval) for severe renal impairment/healthy subjects were 1.43 (1.00, 2.04), 1.38 (0.99, 1.92), and 0.83 (0.61, 1.15) for the plasma doravirine area under the curve from zero to infinity (AUC0-∞), plasma concentration at 24 h postdose (C24), and maximum plasma concentration (Cmax), respectively. Doravirine was generally well tolerated in both groups. Based on the overall efficacy, safety, and PK profile of doravirine, the minor effect of severe renal impairment on doravirine PK observed in this study is not considered clinically meaningful. (This study has been registered at ClinicalTrials.gov under identifier NCT02641067.).

Effect of tildrakizumab (MK-3222), a high affinity, selective anti-IL23p19 monoclonal antibody, on cytochrome P450 metabolism in subjects with moderate to severe psoriasis.

AIMS: Tildrakizumab, an interleukin (IL)-23 inhibitor, is indicated for the treatment of moderate to severe chronic plaque psoriasis. Although tildrakizumab is not metabolized by, and does not alter, cytochrome P450 (CYP) expression in vitro, clinically significant pharmacokinetic effects through changes in systemic inflammation, which alters CYP metabolism, have been well documented. At the time of study conduct, the effect of modulation of inflammation/cytokines, including IL-23 inhibition with tildrakizumab, on CYP metabolism, and therefore the potential for disease-drug interactions, in psoriasis patients was unknown. We therefore assessed whether tildrakizumab alters CYP metabolism in subjects with moderate to severe psoriasis. METHODS: This was an open-label, fixed-sequence, two-period trial. In Period 1 (Day 1), subjects received an oral CYP probe cocktail of up to five drugs (midazolam 2 mg [3A4], caffeine 200 mg [1A2], warfarin 10 mg [2C9], omeprazole 40 mg [2C19] and dextromethorphan 30 mg [2D6]), followed by a 7-day washout. In Period 2, subjects received tildrakizumab 200 mg subcutaneously on Days 1 and 29 and a second CYP probe cocktail on Day 57. Substrate or metabolite pharmacokinetics, safety and changes in Psoriasis Severity Area Index (PASI), interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hs-CRP), were assessed. RESULTS: Twenty subjects (13 men, 7 women) were enrolled. Tildrakizumab had no clinically relevant effect on the pharmacokinetics of any of the probe substrates tested. On Day 57 of Period 2, the median percentage decrease from baseline in PASI score following tildrakizumab was ~93%. There were no clinically relevant changes in IL-6 or hs-CRP. Treatment with tildrakizumab was generally well tolerated. CONCLUSION: In subjects with moderate to severe psoriasis, tildrakizumab 200 mg did not have a discernible effect on CYP metabolism. The potential for clinically significant drug-drug interactions (DDIs) with tildrakizumab in patients with psoriasis is low. The difference in the occurrence of DDIs seen with anti-inflammatory agents in rheumatoid arthritis patients compared with psoriasis patients may be due to the much greater extent of systemic inflammation in rheumatoid arthritis as compared to psoriasis.

Results of a Doravirine-Atorvastatin Drug-Drug Interaction Study.

Doravirine is a novel, highly potent, nonnucleoside reverse transcriptase inhibitor that is administered once daily and that is in development for the treatment of HIV-1 infection. In vitro and clinical data suggest that doravirine is unlikely to cause significant drug-drug interactions via major drug-metabolizing enzymes or transporters. As a common HIV-1 infection comorbidity, hypercholesterolemia is often treated with statins, including the commonly prescribed atorvastatin. Atorvastatin is subject to drug-drug interactions with cytochrome P450 3A4 (CYP3A4) inhibitors. Increased exposure due to CYP3A4 inhibition may lead to serious adverse events (AEs), including rhabdomyolysis. Furthermore, atorvastatin is a substrate for breast cancer resistance protein (BCRP), of which doravirine may be a weak inhibitor; this may increase atorvastatin exposure. The potential of doravirine to affect atorvastatin pharmacokinetics was investigated in a two-period, fixed-sequence study in healthy individuals. In period 1, a single dose of atorvastatin at 20 mg was administered followed by a 72-h washout. In period 2, doravirine at 100 mg was administered once daily for 8 days, with a single dose of atorvastatin at 20 mg concomitantly being administered on day 5. Sixteen subjects were enrolled, and 14 completed the trial; 2 discontinued due to AEs unrelated to the treatment. The atorvastatin area under the curve from time zero to infinity was similar with and without doravirine (geometric mean ratio [GMR] for doravirine-atorvastatin/atorvastatin, 0.98; 90% confidence interval [CI], 0.90 to 1.06), while the maximum concentration decreased by 33% (GMR for doravirine-atorvastatin/atorvastatin, 0.67; 90% CI, 0.52 to 0.85). These changes were deemed not to be clinically meaningful. Both of the study drugs were generally well tolerated. Doravirine had no clinically relevant effect on atorvastatin pharmacokinetics in healthy subjects, providing support for the coadministration of doravirine and atorvastatin.

Evaluation of Doravirine Pharmacokinetics When Switching from Efavirenz to Doravirine in Healthy Subjects.

Doravirine is a novel, potent nonnucleoside reverse transcriptase inhibitor (NNRTI) for the treatment of patients with human immunodeficiency virus type 1 (HIV-1) infection that demonstrates a high genetic barrier to resistance and that has been well tolerated in studies to date. Doravirine is a candidate for patients switching from less-well-tolerated NNRTIs, such as efavirenz. While doravirine is a cytochrome P450 3A4 (CYP3A4) substrate, efavirenz induces CYP3A4; therefore, the pharmacokinetics of both drugs following a switch from efavirenz to doravirine were assessed. This was a 3-period, fixed-sequence, open-label study. Healthy adults were dosed with doravirine at 100 mg for 5 days once daily (QD) (period 1). Following a 7-day washout, efavirenz was administered at 600 mg QD for 14 days (period 2). Subsequently, doravirine was administered at 100 mg QD for 14 days (period 3). Blood samples were collected for pharmacokinetic analyses. Twenty healthy subjects were enrolled, and 17 completed the study. One day after efavirenz cessation, the doravirine area under the concentration-time curve from predosing to 24 h postdosing (AUC0-24), maximum observed plasma concentration (Cmax), and observed plasma concentration at 24 h postdosing (C24) were reduced by 62%, 35%, and 85%, respectively, compared with the values with no efavirenz pretreatment. These decreases recovered to 32%, 14%, and 50% for AUC0-24, Cmax, and C24, respectively, by day 14 after efavirenz cessation. The doravirine C24 reached projected therapeutic trough concentrations, based on in vitro efficacy, on day 2 following efavirenz cessation. Geometric mean efavirenz concentrations were 3,180 ng/ml on day 1 and 95.7 ng/ml on day 15, and efavirenz was present at therapeutic concentrations (>1,000 ng/ml) until day 4. Though doravirine exposure was transiently decreased following efavirenz treatment cessation, dose adjustment may not be necessary to maintain therapeutic concentrations of at least one drug during switching in a virologically suppressed population.

The effects of the CXCR2 antagonist, MK-7123, on bone marrow functions in healthy subjects.

The CXCR2 antagonist MK-7123 causes dose-dependent reductions in absolute neutrophil counts (ANC) and decreases neutrophil tissue responses, but its effects on bone marrow functions are not yet known. We conducted a double-blind, randomized study in 18 healthy subjects comparing the effects of either MK-7123 (30mg, po, daily for 28days) or placebo on peripheral blood counts and bone marrow myeloid cell populations. MK-7123 caused a reversible decrease (approximately 50%) in the ANC as demonstrated on days 1 and 28, the first and last days of the treatment period. Bone marrow aspirate smears and biopsy imprints did not differ in the proportion of mature neutrophils in pretreatment, day 28, day 56 or placebo samples. There were no treatment effects on biopsy or aspirate clot cellularity, myeloid to erythroid or myeloid post-mitotic to mitotic ratios; flow-cytometric analyses of aspirate cells; or bone marrow fat to cell balance as assessed by MRI. MK-7123 was generally well tolerated with neutropenia being the most common adverse event; however, there were no clinical symptoms associated with decreased ANCs. These findings indicate that the CXCR2 antagonist MK-7123 causes rapidly reversible decrease in the ANC without measurable myelosuppressive effects. The results support the development of CXCR2 antagonists as potentially useful anti-inflammatory agents, primarily interrupting neutrophil trafficking.

Tildrakizumab, a novel anti-IL-23 monoclonal antibody, is unaffected by ethnic variability in Caucasian, Chinese, and Japanese subjects.

OBJECTIVE: To evaluate the effect of ethnicity on the pharmacokinetics (PK) of tildrakizumab, a novel anti-IL-23 monoclonal antibody for the treatment of psoriasis. MATERIALS AND METHODS: This was an open-label, 2-part study in healthy adult subjects. In part 1, Japanese subjects and matched Caucasian and Chinese subjects (to Japanese) were assigned to 1 of 3 cohorts and administered tildrakizumab 50, 200, or 400 mg subcutaneously (SC). In part 2, Japanese subjects received tildrakizumab 10 mg/kg IV. Pre- and post-treatment antidrug antibodies were assessed. Safety and tolerability were assessed throughout the study. RESULTS: 59 subjects were enrolled; 53 in part 1 and 6 in part 2. Overall geometric mean AUC∞ was 6.15, 6.05, and 6.32 day×µg/mL/mg in Japanese, Caucasian, and Chinese subjects, respectively, after administration of a single SC dose. Bioavailability was ~92%. Six out of 58 evaluable subjects were positive for post-treatment ADA; 2 of these positive subjects had reduced tildrakizumab exposure. Most AEs were mild in intensity and the most frequent treatment-related AEs were injection site hematoma (15%), injection site pain (10%), and injection site erythema (8%). CONCLUSIONS: The pharmacokinetics of tildrakizumab were similar in Japanese, Caucasian, and Chinese subjects. Tildrakizumab exposure increased proportionally with dose in the range of 50-400 mg. A single SC dose of 50, 200, and 400 mg or a single IV dose of 10 mg/kg was generally well tolerated.

Medications in Patients with Dementia and Behavioral Disturbance.

BACKGROUND: Behavioral disturbance (BD) is common in dementia patients, with no FDA approved medications for this condition. Little data exists on the real-world medication use in this population. OBJECTIVE: To describe real-world medications use in this population. METHODS: A cross-sectional study was conducted using the MarketScan database for outpatient medications and the Cerner database for inpatient medications. The study period was Oct 2015-Jun 2018. Patients with dementia and BD were identified through ICD-10-CM. We examined outpatient medications prescribed during 6-month before or after BD event date, and inpatient medications during inpatient visits, especially on central nervous systems (CNS) drugs including antidementia drugs, antidepressants, antipsychotics, anxiolytics, and anticonvulsants. RESULTS: A total of 56,544 outpatients and 34,245 patient hospitalizations were assessed separately. Among outpatients, patients filled more medications after a BD event. The use of the five CNS drug classes generally increased after a BD event, and the largest increase was seen in antipsychotics (23%to 33%). Among inpatients, the median number of medications used in each hospitalization was 14. The use of antipsychotics was particularly high (64%), followed by anxiolytics (51%). A list of 60 unique medications were suggested to be the commonly used drugs in dementia patients with BD. CONCLUSION: In dementia patients with BD, anti-dementia medications, antidepressants, anticonvulsants, hypnotics and antipsychotics were the most used drug classes. Antidepressants and antipsychotics use were more frequent after a BD event, which suggests a need for safe drugs targeting BD in dementia patients.

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 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.

Evaluation of the Pharmacokinetics of Metformin Following Coadministration With Doravirine in Healthy Volunteers.

Doravirine is a novel nonnucleoside reverse transcriptase inhibitor for the treatment of human immunodeficiency virus type-1 (HIV-1) infection. In vitro and clinical data suggest that doravirine is unlikely to cause significant drug-drug interactions via major drug-metabolizing enzymes or transporters. As a common HIV-1 infection comorbidity, type 2 diabetes mellitus is often treated with metformin. Perturbations of metformin absorption or elimination may affect its safety and efficacy profile; therefore, understanding potential drug-drug interactions between doravirine and metformin is important. An open-label, fixed-sequence, 2-period trial in healthy adults was conducted. Single-dose metformin 1000 mg was administered in period 1; in period 2, doravirine 100 mg was administered once daily on days 1 to 7, and single-dose metformin 1000 mg was administered on day 5. Plasma pharmacokinetics for metformin alone and coadministered with doravirine were assessed. Fourteen participants enrolled and completed the trial. Least-squares geometric mean ratios and 90% confidence intervals of metformin AUC0-∞ , and Cmax following coadministration of metformin and doravirine compared with metformin alone were 0.94 (0.88-1.00) and 0.94 (0.86-1.03), respectively; metformin Tmax and half-life were also minimally impacted. These data indicate that doravirine did not have a clinically relevant effect on the pharmacokinetics of metformin. Metformin alone and coadministered with doravirine was generally well tolerated. These data support coadministration of doravirine 100 mg and metformin 1000 mg without dose adjustment.

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.

A Study to Evaluate Doravirine Pharmacokinetics When Coadministered With Acid-Reducing Agents.

Doravirine is a novel non-nucleoside reverse transcriptase inhibitor indicated for the treatment of human immunodeficiency virus type 1 infection. Because of potential concomitant administration with acid-reducing agents, a drug-interaction trial was conducted to evaluate the potential impact of these types of medications on doravirine pharmacokinetics. In an open-label, 3-period, fixed-sequence trial, healthy adult participants received the following: period 1, a single dose of doravirine 100 mg; period 2, coadministration of a single dose of doravirine 100 mg and an antacid (1600 mg aluminum hydroxide, 1600 mg magnesium hydroxide, and 160 mg simethicone); period 3, 40 mg pantoprazole once daily on days 1-5 coadministered with a single dose of doravirine 100 mg on day 5. There was a minimum 10-day washout between periods. Plasma samples for pharmacokinetic evaluation were collected, and safety was assessed. Fourteen participants (8 male, 6 female) were enrolled, and 13 completed the trial. Geometric mean ratios (90% confidence intervals) for doravirine AUC0-inf , Cmax , and C24 for doravirine + antacid/doravirine were 1.01 (0.92-1.11), 0.86 (0.74-1.01), and 1.03 (0.94-1.12), respectively, and for doravirine + pantoprazole/doravirine were 0.83 (0.76-0.91), 0.88 (0.76-1.01), and 0.84 (0.77-0.92), respectively. Doravirine was generally well tolerated administered alone or with either of the acid-reducing agents. Coadministration of an aluminum/magnesium-containing antacid or pantoprazole did not have a clinically meaningful effect on doravirine pharmacokinetics, supporting the use of acid-reducing agents with doravirine.

Pharmacokinetics of Tildrakizumab (MK-3222), an Anti-IL-23 Monoclonal Antibody, After Intravenous or Subcutaneous Administration in Healthy Subjects.

Tildrakizumab, a high-affinity humanized IgG1k antibody that selectively binds interleukin (IL)-23 p19 subunit of cytokine IL-23 and neutralizes its function, is under investigation for treatment of moderate-to-severe chronic plaque psoriasis. The objective of this analysis was to assess the pharmacokinetics, bioavailability and safety/tolerability of single ascending doses of tildrakizumab after intravenous (IV) and subcutaneous (SC) dosing in healthy subjects. P05661 was a phase 1, single-dose, randomized, placebo-controlled study of tildrakizumab IV doses of 0.1, 0.5, 3 and 10 mg/kg, or placebo. P05776 was a phase 1, single-dose, randomized, placebo-controlled study of tildrakizumab SC doses of 50 or 200 mg, or placebo. After either single IV or SC dosing, tildrakizumab exhibited slow systemic clearance (CL), limited volume of distribution and a long t1/2 . Both the Cmax and the area under the curve (AUC) increased proportionally with doses from 0.1 to 10 mg/kg, or 50-200 mg. The bioavailability of SC dosing was ~80% (90% CI: 62-103%) for 50 mg and ~73% (90% CI: 46-115%) for 200 mg, respectively, versus 0.5 and 3 mg/kg IV. Across both studies, six of 43 evaluable subjects were positive for post-dose antidrug antibodies; two of these were positive for neutralizing antibodies. Most adverse events (AEs) were mild; the most frequent AEs included upper respiratory tract infection and headache. Single doses of tildrakizumab 0.1, 0.5, 3 and 10 mg/kg administered IV or single doses of 50 and 200 mg administered SC were safe and well tolerated in healthy adult subjects.

Multiple Doses of Rifabutin Reduce Exposure of Doravirine in Healthy Subjects.

Doravirine is a nonnucleoside reverse transcriptase inhibitor in clinical development for the treatment of human immunodeficiency virus-1 infection in combination with other antiretroviral therapies. The cytochrome P450 (CYP)3A-dependent metabolism of doravirine makes it susceptible to interactions with modulators of this pathway, including the antituberculosis treatment rifampin. Rifabutin, an alternative antibiotic used to treat tuberculosis, may have a lower-magnitude effect on CYP3A. The aim of this trial was to determine the effect of steady-state rifabutin on doravirine single-dose pharmacokinetics and tolerability. In this open-label, 2-period, fixed-sequence, drug-drug interaction study, healthy subjects received a single dose of doravirine 100 mg alone and coadministered on day 14 of once-daily administration of rifabutin 300 mg for 16 days. Plasma samples were taken to determine doravirine pharmacokinetics, and safety was monitored throughout. Dose adjustment of doravirine in the presence of coadministered rifabutin was explored through nonparametric superposition analysis. Rifabutin reduced doravirine area under the concentration-time curve from time zero to infinite and plasma drug concentration 24 hours postdose with geometric mean ratios ([rifabutin+doravirine]/[doravirine alone]) (90%CIs) of 0.50 (0.45-0.55) and 0.32 (0.28-0.35), respectively. Doravirine apparent clearance increased from 5.9 L/h without rifabutin to 12.2 L/h when coadministered. Doravirine pharmacokinetics with and without coadministered rifabutin were not equivalent. Nonparametric superposition analysis projected that administration of doravirine 100 mg twice daily with rifabutin will restore steady-state trough concentration values to efficacious levels associated with doravirine 100 mg once daily in the absence of CYP3A inducers. Doravirine may be coadministered with rifabutin when the doravirine dose frequency is increased from 100 mg once daily to 100 mg twice daily.