The abuse potential of lemborexant, a dual orexin receptor antagonist, according to the 8 factors of the Controlled Substances Act

RATIONALE

Lemborexant (LEM) is a dual orexin receptor antagonist (DORA) approved in multiple countries including the USA, Japan, Canada, Australia, and several Asian countries for the treatment of insomnia in adults. As a compound with central nervous system activity, it is important to understand the abuse potential of LEM with respect to public health.

OBJECTIVES

This review discusses data for LEM relevant to each of the 8 factors of the United States Controlled Substances Act.

RESULTS

LEM did not demonstrate abuse potential in nonclinical testing and was associated with a low incidence of abuse-related adverse events in clinical study participants with insomnia disorder. Similar to other DORAs that have been evaluated (eg., almorexant, suvorexant (SUV), and daridorexant), LEM and the positive controls (zolpidem and SUV) also showed drug liking in a phase 1 abuse potential study that enrolled subjects who used sedatives recreationally. However, internet surveillance of SUV and the FDA Adverse Events Reporting System suggests that drugs in the DORA class display very low abuse-related risks in the community. Additionally, as described in FDA-approved labeling, it does not carry physical dependence and withdrawal risks.

CONCLUSIONS

LEM, similar to most other prescription insomnia medications, was placed into Schedule IV. However, LEM and other drugs in the DORA class may have a lower potential for abuse as suggested by real-world postmarketing data from federal surveys and internet surveillance, and thus may have lower risks to public health than Schedule IV benzodiazepines and nonbenzodiazepine hypnotics that potentiate GABA signaling.

ECG Evaluation as Part of the Clinical Pharmacology Strategy in the Development of New Drugs: A Review of Current Practices and Opportunities Based on Five Case Studies

The International Conference on Harmonization (ICH) E14 document was revised in 2015 to allow concentration-corrected QT interval (C-QTc) analysis to be applied to data from early clinical pharmacology studies to exclude a small drug-induced effect on QTc. Provided sufficiently high concentrations of the drug are obtained in the first-in-human (FIH) study, this approach can be used to obviate the need for a designated thorough QT (TQT) study. The E14 revision has resulted in a steady reduction in the number of TQT studies and an increased use of FIH studies to evaluate electrocardiogram (ECG) effects of drugs in development. In this review, five examples from different sponsors are shared in which C-QTc analysis was performed on data from FIH studies. Case 1 illustrates a clearly negative C-QTc evaluation, despite observations of QTc prolongation at high concentrations in nonclinical studies. In case 2 C-QTc analysis of FIH data was performed prior to full pharmacokinetic characterization in patients, and the role of nonclinical assays in an integrated risk assessment is discussed. Case 3 illustrates a positive clinical C-QTc relationship, despite negative nonclinical assays. Case 4 demonstrates a strategy for characterizing the C-QTc relationship for a nonracemic therapy and formulation optimization, and case 5 highlights an approach to perform a preliminary C-QTc analysis early in development and postpone the definitive analysis until proof of efficacy is demonstrated. The strategy of collecting and storing ECG data from FIH studies to enable an informed decision on whether and when to apply C-QTc analysis to obviate the need for a TQT study is described.

Population pharmacokinetic-pharmacodynamic analyses of amyloid positron emission tomography and plasma biomarkers for lecanemab in subjects with early Alzheimer's disease

Lecanemab is a humanized immunoglobulin G1 monoclonal antibody that selectively binds to soluble Aβ aggregate species, while demonstrating low affinity for Aβ monomer. This article describes the population pharmacokinetic (PK) and PK/pharmacodynamic (PD) analyses for amyloid plaques, as measured using positron emission tomography (PET), and biomarkers of amyloid pathology as evidenced by Aβ42/40 ratio and plasma p-tau181 following i.v. administration of lecanemab in subjects with early Alzheimer's disease. Lecanemab PKs were well-characterized with a two-compartment model with first-order elimination. Final PK model contained covariate effects of anti-drug antibody positive status, sex, body weight, and albumin on clearance. The time course of amyloid PET standard uptake ratio (SUVr), plasma Aβ42/40 ratio, and p-tau181 were described using indirect response models with lecanemab exposure as a maximum effect function stimulating the reduction of SUVr, and as a linear function increasing Aβ42/40 ratio and decreasing p-tau181 formation rates. PK/PD simulations show that 10 mg/kg biweekly dosing results in larger and faster decrease in SUVr and p-tau181 and increase in Aβ42/40 ratio as compared to 10 mg/kg monthly dose. Furthermore, the PK/PD simulations showed that after treatment discontinuation the brain amyloid re-accumulation to baseline levels is slow with a recovery half-life of ~4 years, whereas plasma Aβ42/40 ratio and p-tau181 return to baseline levels faster than amyloid. Given the relationship between changes in amyloid PET SUVr and soluble biomarkers, the developed PK/PD models can be used to inform lecanemab dose regimens in future clinical studies.

Effect of alcohol coadministration on the pharmacodynamics, pharmacokinetics, and safety of lemborexant: A randomized, placebo-controlled crossover study

BACKGROUND

Lemborexant is a dual orexin receptor antagonist approved to treat insomnia in adults in several countries including the USA, Canada, and Japan.

AIMS

This study was conducted to investigate effects of lemborexant and alcohol coadministration on postural stability, cognitive performance, and the pharmacokinetics, safety, and tolerability of lemborexant.

METHODS

This was a Phase 1, double-blind, placebo-controlled, four-period crossover study in 32 healthy adults. Individuals were randomized into one of four treatment sequences to receive single doses of placebo, lemborexant 10 mg (LEM10), alcohol (males, 0.7 g/kg; females, 0.6 g/kg), and LEM10 plus alcohol, each separated by a 14-day washout. Postural stability (body sway) was measured by ataxiameter and a cognitive performance assessment battery evaluated four domains of attention and memory.

RESULTS

Pharmacodynamic outcomes were analyzed for the 18 participants who completed all four treatments. Change from baseline in body sway showed no significant differences between lemborexant plus alcohol versus alcohol alone. Compared with alcohol alone, coadministration of lemborexant with alcohol showed additive negative effects on cognitive performance domains, corresponding approximately with peak plasma lemborexant concentrations (median = 1.5 h). Cognitive performance was also impaired with lemborexant alone at 0.5 and 2 h in this experimental paradigm with morning dosing. Alcohol increased plasma lemborexant exposure by 70% based on area under the curve to 72 h, and increased peak plasma lemborexant concentrations by 35%. The most commonly reported treatment-emergent adverse event was somnolence.

CONCLUSION

Coadministration of lemborexant with alcohol showed additive negative effects on cognitive measures, but not on postural stability, compared with alcohol alone. Lemborexant exposure was increased with alcohol. Lemborexant alone or with alcohol was well tolerated. Patients are advised not to consume alcohol with lemborexant.

0453 Lemborexant Exposure Is Independent of Race

Introduction

Some hypnotic treatments for insomnia require dosing consideration due to exposure differences based on patient characteristics. Lemborexant (LEM) is a dual orexin receptor antagonist approved in multiple countries for the treatment of adult insomnia. LEM is not associated with exposure differences based on sex, age, or BMI that impact dosing. The potential impact of race on exposure was determined in two stand-alone pharmacokinetic (PK) studies and by modeling data from studies comprising the LEM clinical development program, which included healthy subjects and insomnia patients.

Methods

Study 003 (NCT02039089) was a single-center, multiple-dose, randomized, double-blind, placebo-controlled, parallel-group study in healthy Japanese and White subjects. Study 014 (NCT04555733) was a phase 1, single center, open-label, single and multiple oral dose study in healthy Chinese subjects. Additionally, effect of race on LEM exposure was independently examined as part of a population PK analysis incorporating LEM data from 9 Phase 1 studies (n=407), and Studies 201 (NCT01995838; n=235), 303 (NCT02952820; n=726) and 304 (NCT02783729; n=524) (Lalovic et al., 2020). Plasma concentrations of LEM were quantified from plasma by validated liquid chromatography with tandem mass spectrometry. Adverse events (AE) were recorded.

Results

Exposure of LEM increased in an approximately dose-proportional manner across the dose range (2.5 mg to 25 mg) in studies 003 and 014. There were no significant exposure differences between Japanese and White subjects following single LEM10 administration on Day 1 in Study 003 (maximum concentration [Cmax] mean[SD], ng/mL: Japanese, 46.5[25.8]; White, 47.3[28.1]; area under the curve from time zero to 24h [AUC0-24] mean[SD], ng·h/mL: Japanese, 231[40.2]; White, 208[83.4]) or when comparing PK data from Chinese subjects in Study 014 following single dose administration on Day 1 (Cmax mean[SD], ng/mL: LEM5, 29.8[12.8]; LEM10, 56.2[16.9]; LEM25, 116[46.8]; AUC0-24 mean[SD], ng·h/mL: LEM5, 106[29.9]; LEM10, 205[35.6]; LEM25, 549[116]) to Japanese and White subjects in Study 003. These results are supported by the cross-study, population PK model-based analysis, indicating no significant clinical or statistical differences in LEM PK attributable to the intrinsic factor race.

Conclusion

LEM exposure is not significantly affected by race. Therefore, dosing of LEM can be consistent across patient populations from different racial groups.

Support (If Any)

Eisai Inc.

Effects of Lemborexant on the Pharmacokinetics of Oral Contraceptives: Results From a Phase 1 Drug-Drug Interaction Study in Healthy Females

Lemborexant is a dual orexin receptor antagonist approved in multiple countries including the United States, Canada, and Japan for the treatment of insomnia in adults. As women of childbearing potential may be prescribed insomnia drugs, a drug‐drug interaction study was conducted. This single‐center, open‐label, fixed‐sequence study examined potential drug‐drug interactions between lemborexant and an oral contraceptive (OC) in healthy females (18–44 years, n = 20). The purpose of this study was to determine the effect of lemborexant 10 mg (at steady state) on the pharmacokinetics of a single dose of OC (0.03 mg ethinyl estradiol and 1.5 mg norethindrone acetate), assess the effect of a single dose of OC on lemborexant pharmacokinetics, and evaluate safety and tolerability of lemborexant and OC coadministration. Ethinyl estradiol maximum plasma drug concentration was not altered by lemborexant coadministration; area under the curve from zero time to the last quantifiable concentration was slightly increased, by 13%. No clinically relevant effects on norethindrone acetate pharmacokinetics were observed. Coadministration of OC with lemborexant had no clinically relevant effect on the steady‐state pharmacokinetics of lemborexant. Adverse events were consistent with the known safety profile. These results support the conclusion that lemborexant and OC can be coadministered without dose adjustment.

Effect of hepatic impairment on pharmacokinetics, safety, and tolerability of lemborexant

Lemborexant, a dual orexin receptor antagonist, is approved in the United States, Japan, and Canada for the treatment of insomnia in adults. This phase I, multicenter, open‐label, parallel‐group study assessed the impact of mild or moderate hepatic impairment (HI) on lemborexant pharmacokinetics and metabolism. The pharmacokinetics, tolerability, and safety of lemborexant were evaluated in subjects with mild (Child–Pugh class A) or moderate (Child–Pugh class B) HI and healthy age‐, sex‐, and body mass index (BMI)‐matched control subjects (n = 8 subjects/group). Subjects received a single oral dose of lemborexant 10 mg (LEM10). Blood samples were collected up to 312 hours post dosing for lemborexant pharmacokinetics assessments. Median time to maximum plasma concentration was similar across all groups. Compared with healthy subjects, exposure measures (maximum plasma concentration [C_max] and area under the curve extrapolated to infinity [AUC_0‐inf]) increased by ~58% (C_max) and ~25% (AUC_0‐inf) in subjects with mild HI and ~22% (C_max) and ~54% (AUC_0‐inf) in subjects with moderate HI. Clearance decreased by 20% and 35% in subjects with mild and moderate HI, respectively, versus healthy subjects. Lemborexant unbound fraction was similar in all groups (range: 0.060–0.065). All treatment‐emergent adverse events (TEAEs) were mild in severity; no serious TEAEs occurred. In conclusion, following a single LEM10 dose, lemborexant exposure was similar in subjects with mild HI and increased in subjects with moderate HI versus healthy subjects. No dose adjustment is required in subjects with mild HI. Dosing in subjects with moderate HI should be restricted to 5 mg. Lemborexant was well tolerated in all groups.

Physiologically-based pharmacokinetic modeling to predict drug interactions of lemborexant with CYP3A inhibitors

Lemborexant, a recently approved dual orexin receptor antagonist for treatment of adults with insomnia, is eliminated primarily by cytochrome P450 (CYP)3A metabolism. The recommended dose of lemborexant is 5 mg once per night, with a maximum recommended dose of 10 mg once daily. A physiologically-based pharmacokinetic (PBPK) model for lemborexant was developed and applied to integrate data obtained from in vivo drug-drug interaction (DDI) assessments, and to further explore lemborexant interaction with CYP3A inhibitors and inducers. The model predictions were in good agreement with observed pharmacokinetic data and with DDI results from clinical studies with CYP3A inhibitors, itraconazole and fluconazole. The model further predicted that DDI effects of weak CYP3A inhibitors (fluoxetine and ranitidine) are weak, and effects of moderate inhibitors (erythromycin and verapamil) are moderate. Based on the PBPK simulations and clinical efficacy and safety data, the maximum daily recommended lemborexant dose when administered with weak CYP3A inhibitors is 5 mg; co-administration of moderate and strong inhibitors should be avoided except in countries where 2.5 mg has been approved.

Effect of severe renal impairment on pharmacokinetics, safety, and tolerability of lemborexant

The primary aim of this study was to examine the effect of severe renal impairment (SRI) on the pharmacokinetics of lemborexant, a dual orexin receptor antagonist indicated for the treatment of insomnia. A phase 1 multicenter, single‐dose, open‐label, parallel‐group study was conducted in subjects with SRI not requiring dialysis (estimated glomerular filtration rate 15–29 ml/min/1.73 m²; n = 8) compared with demographically matched healthy subjects with normal renal function (n = 8). Plasma levels of lemborexant and its metabolites were measured over 240 h following a single oral 10‐mg dose administered in the morning. Relative to subjects with normal renal function, lemborexant maximum plasma concentration (C_max) was similar, whereas area under the plasma concentration–time curve from zero to time of last quantifiable concentration (AUC_(0‐t)) and AUC from zero to infinity (AUC_(0‐inf)) were about 1.5‐fold higher in subjects with SRI. The geometric mean ratios (90% confidence interval) were 104.8 (77.4–142.0), 150.5 (113.2–200.3), and 149.8 (113.1–198.6) for C_max, AUC_(0‐t), and AUC_(0‐inf), respectively. In both groups, the median lemborexant time to C_max (t_max) was 1 h, and the mean unbound fraction of lemborexant was ~7%. For the M4, M9, and M10 metabolites, C_max was reduced ~20% and exposure (AUC_(0‐t) and AUC_(0‐inf)) was ~1.4‐ to 1.5‐fold higher in subjects with SRI versus healthy subjects; t_max was delayed ~1.5–2 h for M4 and M10. All treatment‐emergent adverse events were mild or moderate. Lemborexant pharmacokinetics were not sufficiently altered to warrant a dose adjustment for subjects with renal impairment.

Evaluation of the CYP3A and CYP2B6 Drug-Drug Interaction Potential of Lemborexant

Lemborexant is approved for treating insomnia and is under investigation for treating irregular sleep‐wake rhythm disorder. Based on in vitro drug‐drug interaction (DDI) characteristics, phase 1, open‐label DDI studies were conducted to evaluate lemborexant's cytochrome P450 3A (CYP3A) and CYP2B6 interaction potential. Interactions between lemborexant 10 mg and strong and moderate CYP3A inhibitors (itraconazole and fluconazole), a strong CYP3A inducer (rifampin), and CYP3A (midazolam) and CYP2B6 substrates (bupropion) were evaluated. Coadministration of lemborexant with itraconazole or fluconazole resulted in 1.4‐ to 1.6‐fold and 3.7‐ to 4‐fold increases in lemborexant maximum observed concentration (C_max) and area under the concentration‐time curve from zero time extrapolated to infinity (AUC_0‐inf), respectively. Coadministration of lemborexant with rifampin resulted in >90% decreases in lemborexant C_max and AUC_0‐inf. Midazolam exposure was not affected. Coadministration of lemborexant with bupropion resulted in 49.9% and 45.5% decreases in S‐bupropion C_max and AUC_0‐inf, respectively.Comparison of estimated exposures for patients in phase 3 trials who were/were not receiving concomitant weak CYP3A inhibitors substantiated the DDI pharmacokinetic findings. Lemborexant was generally well tolerated in the phase 1 studies. In summary, lemborexant does not affect the pharmacokinetics of CYP3A substrates and has potential to induce CYP2B6. Consistent with in vitro findings, moderate and strong CYP3A inhibitors and inducers affected the pharmacokinetics of lemborexant; hence, patients taking lemborexant 5 or 10 mg should avoid coadministration with moderate and strong CYP3A inhibitors and inducers.

Population Pharmacokinetics and Exposure-Response Analyses for the Most Frequent Adverse Events Following Treatment With Lemborexant, an Orexin Receptor Antagonist, in Subjects With Insomnia Disorder

Lemborexant is a novel orexin receptor antagonist approved in the United States and Japan for the treatment of insomnia. This article describes the population pharmacokinetics (PK) of lemborexant and the relationship of its daily steady-state exposure (Cav,ss ) to the probability of most frequent treatment-emergent adverse events (TEAEs). The 12 230-observation, 1892-subject PK data set included data from 12 clinical studies with predominantly female subjects (66%) ranging in age from 18 to 88 years and from 37 to 168 kg in body weight. The 1664-subject exposure-response data set included data from 3 late-stage studies. Lemborexant pharmacokinetics were described by a 3-compartment model with combined first- and zero-order absorption with lag time and linear elimination. Oral clearance decreased with increasing body mass index (exponent, -0.428), increasing alkaline phosphatase levels (exponent, -0.118), and was 26% lower in the elderly (≥65 years). Across the adverse event analysis, the frequency of subjects experiencing TEAEs during active treatment ranged from approximately 3% to 8%, in the range estimated for placebo. With and without adjustment for age, lemborexant exposure (Cav,ss ) was not a clinically meaningful linear predictor of the probability of specific TEAEs: somnolence, nasopharyngitis, flu/influenza, urinary tract infection, upper respiratory tract infection, or headache. Given the small effect sizes of covariates of the PK model and a low degree of association of lemborexant TEAEs and exposure over the range of phase 3 (therapeutic) 5- and 10-mg doses, lemborexant can be safely administered without the need for dose adjustment.

Effect of gastric acid-reducing agents on the pharmacokinetics and efficacy of lemborexant

Lemborexant is a dual orexin receptor antagonist approved for treating insomnia. As the solubility of lemborexant is pH-sensitive, the impact of the gastric acid-reducing agent (ARA), famotidine, on lemborexant pharmacokinetics was evaluated in a Phase 1 study. Additionally, post hoc analysis of data from Phase 3 studies examined the potential effect of concomitant ARAs on patient-reported/subjective sleep onset latency (sSOL) in subjects with insomnia. Coadministration of lemborexant 10 mg with famotidine decreased the maximum observed concentration by 27% and delayed time of maximum observed concentration by 0.5 hours. Famotidine did not affect overall lemborexant exposure based on comparison of area under the concentration curves. Concomitant ARA use in the Phase 3 studies did not impact the effect of lemborexant on sSOL; the change from baseline during the last 7 nights of 1 month of treatment with lemborexant 10 mg was -17.1 minutes with vs -17.9 minutes without ARAs. Collectively, these results indicate that lemborexant can be coadministered with ARAs.

Pharmacokinetics, Pharmacodynamics, and Safety of the Dual Orexin Receptor Antagonist Lemborexant: Findings From Single-Dose and Multiple-Ascending-Dose Phase 1 Studies in Healthy Adults

Lemborexant, a dual orexin receptor antagonist, is approved for the treatment of insomnia and is under investigation for treating other sleep disorders. Here we summarize pharmacokinetic, pharmacodynamic, and safety data from 3 randomized, double‐blind, placebo‐controlled phase 1 studies: single ascending doses in healthy adults (Study 001; 1‐200 mg; N = 64), multiple ascending doses in healthy and elderly adults (Study 002; 2.5‐75 mg; N = 55), and multiple doses in healthy white and Japanese adults (Study 003; 2.5‐25 mg; N = 32). Lemborexant exposure increased with increasing dose. The time to maximum concentration ranged from approximately 1 to 3 hours for the 5‐ and 10‐mg doses. The mean effective half‐life was 17 hours for lemborexant 5 mg and 19 hours for lemborexant 10 mg. The plasma concentration at 9 hours postdose was 27% of the maximum concentration following multiple dosing with lemborexant 10 mg. There were no clinically relevant effects on next‐morning residual sleepiness (Karolinska Sleepiness Scale, Digital Symbol Substitution Test, Psychomotor Vigilance Test) for doses through 10 mg/day, indicating no effect of residual plasma concentrations on next‐day residual effects. Lemborexant was well tolerated across the doses tested. There were no clinically relevant effects of age, sex, or race on lemborexant pharmacokinetics, pharmacodynamics, or safety. These results suggest that lemborexant at doses through 25 mg provides an overall pharmacokinetic, pharmacodynamic, and safety profile suitable for obtaining the target pharmacologic effect supporting treatment of insomnia while minimizing residual effects during wake time.

On-the-road driving performance the morning after bedtime administration of lemborexant in healthy adult and elderly volunteers

Study Objectives

To assess potential effects of lemborexant on next-morning driving performance in adult and elderly healthy volunteers.

Methods

Randomized, double-blind, double-dummy, placebo and active-controlled, four period incomplete crossover study in 48 healthy volunteers (22 females), 23–78 years old. Participants were treated at bedtime for eight consecutive nights with two of three dose levels of lemborexant (2.5, 5, or 10 mg), zopiclone 7.5 mg (on the first and last night with placebo on intervening nights), or placebo. Driving performance was assessed in the morning on days 2 and 9 using a standardized highway driving test in normal traffic, measuring standard deviation of lateral position (SDLP). Drug–placebo differences in SDLP >2.4 cm were considered to reflect clinically meaningful driving impairment.

Results

Mean drug–placebo differences in SDLP following lemborexant 2.5, 5, and 10 mg on days 2 and 9 were 0.74 cm or less. The upper bound of the 95% confidence intervals (CIs) for lemborexant treatment groups were all below 2.4 cm and the 95% CIs included zero, indicating that the effects were neither clinically meaningful nor statistically significant. Symmetry analysis further supported the lack of clinically meaningful impairment with lemborexant.

Conclusions

When assessed starting ~9 h after lemborexant administration at bedtime the previous night, there was no statistically significant or clinically meaningful effect on driving performance in healthy adults and elderly, as assessed by either mean differences in SDLP relative to placebo or symmetry analysis. In this study, lemborexant at doses up to 10 mg was well-tolerated.

Clinical Trial Registration

clinicaltrials.gov, NCT02583451. https://clinicaltrials.gov/ct2/show/NCT02583451.