Pharmacokinetics and bioequivalence of a molnupiravir tablet formulation compared with the molnupiravir capsule formulation in healthy adult participants—a randomized, open-label, three-period, crossover study

Molnupiravir, a prodrug of β-D-N⁴-hydroxycytidine (NHC), is administered orally as four 200 mg capsules twice daily for 5 days to treat COVID-19. This randomized, open-label, four-treatment sequence, three-period crossover study (NCT06615869) evaluated the bioequivalence of a new single 400 mg oral dose of the molnupiravir tablet Formulation 1 (F1) to a 400 mg oral dose of the currently authorized molnupiravir capsule formulation (administered as two 200 mg capsules) by comparing the plasma pharmacokinetics of NHC following administration to healthy participants. The effect of food on the plasma NHC pharmacokinetics following the administration of the molnupiravir F1 tablet, safety and tolerability of a single oral 400 mg dose of molnupiravir, and pharmacokinetics of a separate molnupiravir tablet Formulation 2 (F2) with a slower <i>in vitro</i> dissolution rate were also evaluated. The geometric mean ratio and 90% confidence intervals ([1 × 400-mg F1 tablet]/[2 × 200 mg reference capsules]) for plasma NHC area under the concentration-time curve (AUC) from time 0-infinity, AUC from time 0-last measurable time point, and maximum plasma concentration were 1.00 (0.97, 1.03), 1.00 (0.97, 1.03), and 0.98 (0.93, 1.03), respectively. All estimates were within prespecified limits (0.80, 1.25), demonstrating bioequivalence of the molnupiravir F1 tablet and reference capsules. Administration of the F1 tablet with a high-fat meal did not meaningfully impact the rate or extent of absorption. The pharmacokinetics of the F2 tablet were similar to the reference capsules. Administered in either formulation, molnupiravir was generally safe and well tolerated. In conclusion, a single 400 mg tablet of molnupiravir is bioequivalent to the reference capsule formulation in healthy adults.CLINICAL TRIALSThis study was registered at ClinicalTrials.gov as NCT06615869.