This clinical study is designed to study the mass balance of a single dose of varegacestat in healthy male participants.

This is a single-center, open-label, Phase 1, mass balance study of varegacestat administered as a single oral dose (containing ~100 µCi) [14C]varegacestat in 6 healthy male participants.

Following completion of Screening and Day -1 assessments and an overnight fast of at least 10 hours, eligible participants will be administered a single dose (containing ~100 µCi) [14C]varegacestat as 2 oral capsules followed by approximately 240 mL room temperature filtered water on the morning of Day 1. Whole blood, plasma, urine, feces, and vomitus (if any, up to 24 hours post-dose) will be collected over at least 168 hours post-dose.

Inclusion Criteria:

• Be a male participant between 18 and 55 years of age, inclusive, at Screening.
• Medically healthy based on the absence of clinically significant abnormal vital sign measurements, clinical laboratory test results (especially tests for renal and hepatic function), resting 12-lead Electrocardiogram (ECG) evaluation, and physical examination, as determined by the Investigator at Screening and the Check-In visit.

Exclusion Criteria:

• Have taken an investigational drug or participated in a clinical trial evaluating an investigational drug or device within 30 days (or 5 half-lives) prior to the study drug dose, whichever is longer.
• Have participated in a radiolabeled drug study or have been otherwise exposed to significant diagnostic (excluding dental X-rays), therapeutic, or occupational radiation, where exposure is made known to the Investigator, within one year prior to admission to the clinic for this study. The total estimated 12-month exposure to radio material or ionizing radiation should be below the CFR recommended levels considered safe (per US Title 21 CFR 361.1) or below 3000 mrem.
• Any condition which, in the opinion of the Investigator and/or Sponsor, would jeopardize participant safety or compliance with the Protocol.