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.