RT Journal Article
SR Electronic
T1 <strong>Characterization of Pharmacokinetics, Biotransformation and Elimination of Pomotrelvir Orally Administered in Healthy Male Adults Using Two [<sup>14</sup>C]-labeled Microtracers</strong><strong> with Separate Labeling Positions</strong>
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP DMD-AR-2023-001439
DO 10.1124/dmd.123.001439
A1 Ziping Yang
A1 Shekman L. Wong
A1 David Cha
A1 David Wilfret
A1 David Turnquist
A1 Andrew Plummer
A1 Eric van Ingen
A1 Brian P Kearney
YR 2023
UL http://dmd.aspetjournals.org/content/early/2023/09/08/dmd.123.001439.abstract
AB Pomotrelvir is an orally bioavailable, target antiviral inhibitor of the main protease (Mpro) of coronaviruses (CoVs), including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of Coronavirus Disease 2019 (COVID-19). The pharmacokinetics, metabolism and elimination of two [14C]-labeled microtracers of 5 µCi/700 mg pomotrelvir with separate labeling positions (isotopomers), [lactam carbonyl-14C-pomotelvir] and [benzene ring-U-14C-pomotrelvir], following a single oral dose in healthy adult males was evaluated in two separate cohorts. Pomotrelvir was rapidly absorbed and eliminated primarily through metabolism and subsequently excreted via urine and feces. There were no differences in pomotrelvir pharmacokinetics between the two cohorts. The mean total radioactive dose recovered was 93.8% (n=8) in the lactam cohort (58% in urine and 36% in feces) and 94.2% (n=8) in the benzene cohort (75% in urine and 19% in feces), with {greater than or equal to} 80% of [14C] recovered within 96 hours after dosing. About 5% and 3% of the intact pomotrelvir was recovered in feces and urine, respectively. Eleven major metabolites were detected and characterized using LC-accelerator mass spectrometry (AMS) and LC-MS/MS methods, with 3 and 6 different metabolites elucidated in the samples collected from lactam and benzene cohorts, respectively, and 2 metabolites observed in both cohorts. The major metabolism pathway of pomotrelvir is through hydrolysis of its peptide bonds followed by phase II conjugations. These results support that the application of two radiolabeled isotopomers provided a comprehensive metabolite profiling analysis and was a successful approach in identifying the major disposition pathways of pomotrelvir that has complex routes of metabolism. Significance Statement An unconventional approach using two differentially labeled [14C] microtracers, [lactam carbonyl-14C-pomotrelvir] and [benzene ring-U-14C-pomotrelvir] evaluated the mass balance of orally administered pomotrelvir in healthy adult males in two separate cohorts. The radioactive dose recovered in excreta was about 94% for both cohorts. While the two isotopomers of the radiolabeled-pomotrelvir showed no major differences in pharmacokinetics overall, they allowed for differential detection of their radiolabeled metabolites and appropriate characterization of their plasma exposure and excretion in urine and feces.