Based on various healthy authorities feedback on PAXLOVID submission, this study is no longer required.

This study is to characterize mass balance and further the understanding of human pharmacokinetics, metabolism, and excretion of radiolabeled [14C]PF-07321332 in healthy male participants following oral administration with ritonavir.

Inclusion Criteria:

• Participants who are overtly healthy as determined by medical evaluation including medical history, physical examination (PE), laboratory tests, vital signs and standard 12 lead ECGs.
• Body mass index (BMI) of 17.5 to 30.5 kg/m2; and a total body weight >50 kg (110 lb).
• Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures

Exclusion Criteria:

• Positive test result for SARS-CoV-2 infection at the time of Screening or Day -1.
• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurological, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at the time of dosing).
• Clinically relevant abnormalities requiring treatment (eg, acute myocardial infarction, unstable ischemic conditions, evidence of ventricular dysfunction, serious tachy or brady arrhythmias) or indicating serious underlying heart disease (eg, prolonged PR interval, cardiomyopathy, heart failure greater than New York Heart Association (NYHA) 1, underlying structural heart disease, Wolff Parkinson-White syndrome).
• Any condition possibly affecting drug absorption (eg, gastrectomy, cholecystectomy).
• History of human immunodeficiency virus (HIV) infection, hepatitis B, or hepatitis C; positive testing for HIV, hepatitis B surface antigen (HBsAg), or hepatitis B surface antibody (HCVAb). Hepatitis B vaccination is allowed.
• Use of prescription or nonprescription drugs and dietary and herbal supplements within 7 days or 5 half lives (whichever is longer) prior to the first dose of study intervention.
• Participant who have received a COVID-19 vaccine within 7 days before screening or admission, or who are to be vaccinated with a COVID-19 vaccine at any time during the study confinement period.
• A positive urine drug test.
• Participants enrolled in a previous radio-nucleotide study or who have received radiotherapy within 12 months prior to screening or such that total radioactivity would exceed acceptable dosimetry (ie, occupational exposure of 5 rems per year).

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.