Pharmacokinetic profiling of limnetrelvir in non-Japanese and Japanese populations: results of two phase 1 single- and multiple-dose studies.

COVID-19's main protease (Mpro) unique structure and function, which are conserved among coronaviruses, make it an attractive target for viral inhibition. Limnetrelvir is a novel Mpro inhibitor intended for once-daily administration. The pharmacokinetics, safety, and tolerability results of two phase 1 studies of limnetrelvir are reported herein. These studies consisted of a first-in-human, single-, and multiple-ascending dose study in healthy non-Japanese participants and a single- and multiple-dose study in healthy Japanese participants. Across both studies, a total of 104 participants received limnetrelvir single doses ranging from 200 to 800 mg and multiple doses from 200 to 800 mg QD for 10 days. The harmonic mean half-life of limnetrelvir ranged from 6 to 21 h following a single dose. No clinically significant differences in exposures were observed between Japanese and non-Japanese participants. Limnetrelvir was generally well tolerated in both studies in healthy participants with up to 10 days of dosing, with only mild or moderate adverse events observed.CLINICAL TRIALSThis study is registered with ClinicalTrials.gov as NCT05691699 and NCT06009237.