This is a Phase 1, open label study in healthy male participants to study the Absorption, Distribution, Metabolism, and Excretion of [14C]-MRM-3379 drug following a single oral dose.

Inclusion Criteria:

1. Male of any race, between 18 and 55 years of age, inclusive.
2. Body mass index between 18.0 and 32.0 kg/m2, inclusive, and a body weight between 50 and 110 kg, inclusive.
3. In good health, as determined by medical history, and as assessed by the investigator (or designee).
4. Able to comprehend and are willing to sign the ICF and abide by the trial restrictions.

Exclusion Criteria:

1. History of or current medical condition that would place the participant at risk from study participation.
2. Administration of any vaccine within 30 days prior to dosing.
3. Use or intend to use any medications/products known to alter drug absorption, metabolism, or elimination processes, including St. John's wort, within 30 days prior to dosing, considered to potentially impact participant safety or the objectives of the trial, as determined by the investigator (or designee).
4. Participation in a clinical trial involving administration of an IMP (new chemical entity) in the past 30 days or 5 half-lives of that drug (if known) prior to dosing, whichever is longer.
5. Have previously completed or withdrawn from this trial or any other trial investigating MRM-3379 or have previously received MRM-3379.
6. Participants who have previously been dosed in >2 radiolabeled drug studies in the last 12 months. For participants who have previously been dosed in ≤2 radiolabeled drug studies within the last 12 months, the previous radiolabeled dose must be at least 4 months prior to check-in to the trial site where exposures are known to the investigator or 6 months prior to check-in to the trial site for a radiolabeled drug trial where exposures are not known to the investigator. The total 12-month exposure from this trial and a maximum of 2 other previous radiolabeled studies must be within the CFR recommended levels considered safe, per US Title 21 CFR 361.1.
7. Participants with exposure to significant diagnostic or therapeutic radiation or current employment in a job requiring radiation exposure monitoring within 12 months prior to check-in.
8. Participants who, in the opinion of the investigator (or designee), should not participate in this trial.