The purpose of the study is to understand how the study medicine ARV-471 is processed in the body of healthy males and females who do not have the potential to have children.

This study is seeking for participants who:

• are healthy males and females who do not have the potential to have children.
• are 18 years of age or older.
• weigh more than 110 pounds.

About 6 participants each will receive a single dose of either type of ARV-471. They are taken as liquid suspensions by mouth. Participants will stay in the study site for about 13 days and 12 nights.

Inclusion Criteria:

• Participants aged 18 years or older (or the minimum age of consent in accordance with local regulations) at screening.
• Male and female participants of non-childbearing potential who are overtly healthy as determined by medical evaluation including medical history, physical examination, laboratory tests, and ECG monitoring.
• Total body weight >50 kg (110 lb).
• An informed consent document signed and dated by the subject.
• Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, and other study procedures.

Exclusion Criteria:

• 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).

  • Any condition possibly affecting drug absorption (eg, gastrectomy, cholecystectomy).
  • History of clinically significant thromboembolic or cerebrovascular events.
  • History of HIV infection, hepatitis B, or hepatitis C; positive testing for HIV, HBsAg, or HCVAb. Hepatitis B vaccination is allowed.

• Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.

• Use of prescription or nonprescription medications, including vitamins, dietary and herbal supplements are prohibited in this study. A washout of 7 days or 5 half-lives (whichever is longer) prior to the first dose of study intervention is required, or a longer washout is required for those that fall into the categories below:

  • Moderate/strong CYP3A inducers; these are prohibited within 14 days plus 5 half-lives prior to the first dose of study intervention.
  • Moderate/strong CYP3A inhibitors; these are prohibited within 14 days or 5 half lives (whichever is longer) prior to the first dose of study intervention.

• Previous administration with an investigational product (drug or vaccine) within 30 days (or as determined by the local requirement) or 5 half lives preceding the first dose of study intervention used in this study (whichever is longer).

• A positive urine drug test.

• Screening supine BP ≥140 mm Hg (systolic) or ≥90 mm Hg (diastolic), following at least 5 minutes of supine rest.

• Renal impairment as defined by an eGFR in adults of <60 mL/min.

• Hematuria as defined as >1+ heme on urine dipstick.

• Proteinuria or Albuminuria as defined as >1+ protein on urine dipstick OR positive dipstick for albumin OR Albumin/Cr ratio on spot urine (UA) >30 mg/g.

• Standard 12 lead ECG that demonstrates clinically relevant abnormalities that may affect participant safety or interpretation of study results (eg, QTcF >450 ms, complete LBBB, signs of an acute or indeterminate age myocardial infarction, ST T interval changes suggestive of myocardial ischemia, second- or third-degree AV block, or serious bradyarrhythmias or tachyarrhythmias).

• Participants with ANY of the following abnormalities in clinical laboratory tests at screening, as assessed by the study specific laboratory and confirmed by a single repeat test, if deemed necessary:

  • AST or ALT level >1.0× ULN;
  • Total bilirubin level >1.0 × ULN; participants with a history of Gilbert's syndrome may have direct bilirubin measured and would be eligible for this study provided the direct bilirubin level is ≤ ULN.

• History of alcohol abuse or binge drinking and/or any other illicit drug use or dependence within 6 months of Screening. Binge drinking is defined as a pattern of 5 (male) and 4 (female) or more alcoholic drinks in about 2 hours. As a general rule, alcohol intake should not exceed 14 units per week (1 unit = 8 ounces (240 mL) beer, 1 ounce (30 mL) of 40% spirit, or 3 ounces (90 mL) of wine).

• Blood donation (excluding plasma donations) of approximately 1 pint (500 mL) or more within 60 days prior to dosing.

• History of sensitivity to heparin or heparin induced thrombocytopenia.

• Unwilling or unable to comply with the criteria in the Lifestyle Considerations section of this protocol.

• Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members.

• History of sensitivity to ARV-471 or any of the formulation components of ARV 471.

• Participants with a history of irregular bowel movements (eg, regular episodes of diarrhea or constipation, or IBS).

• Participants enrolled in a previous radionucleotide study or who have received radiotherapy within 12 months prior to screening or such that total radioactivity would exceed acceptable dosimetry.

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.