A Clinical Study To Understand How Radiolabeled MK-5475 Is Taken Up By The Body, Broken Down And Then Removed From The Body in Healthy Participants (MK-5475-011)

An Open-label Phase 1 IV Study to Evaluate Metabolism, Excretion, and Mass Balance of [14C]MK-5475 in Healthy Participants

The goal of this study is to understand how radiolabeled MK-5475 administered intravenously (IV) is taken up by the body, broken down and then removed from the body in healthy male participants. The study also aims to understand how much of the compound is broken down and how much leaves the body unchanged.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Drug: [14C] MK-5475

• Study Type: Interventional
• Enrollment (Actual): 8
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Wisconsin
    • Madison, Wisconsin, United States, 53704
      • Labcorp Clinical Research Unit Inc. (Site 0001)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Is in good health.
• Body mass index (BMI) >18 and ≤32 kg/m2, inclusive.

Exclusion Criteria:

• Has history of clinically significant endocrine, gastrointestinal, cardiovascular, hematological, hepatic, immunological, renal, respiratory, genitourinary, or major neurological (including stroke and chronic seizures) abnormalities or diseases.
• Has significant multiple and/or severe allergies, or has had an anaphylactic reaction or significant intolerability to prescription or nonprescription drugs or food.
• Has had a major surgery and/or donated or lost 1 unit of blood (approximately 500 mL) or blood products within 4 weeks prior to the prestudy (screening).
• Has history of exposure to significant diagnostic or therapeutic radiation or current employment in a job requiring radiation exposure monitoring within 12 months prior to check-in.
• Has participated in more than 3 radiolabeled drug studies in the last 12 months.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: [14C] MK-5475; [14C] MK-5475 is administered as single IV bolus dose of 100μg on Day 1.	Drug: [14C] MK-5475; [14C] MK-5475 is administered as a single IV bolus dose in healthy male participants on Day 1.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Amount Excreted in Urine (Aeu)	Amount of [14C]MK-5475 and its metabolites excreted in urine (Aeu) derived from urine collections at each sampling interval.	At designated time points (Up to ~ 23 days)
Cumulative Aeu	Cumulative amount of [14C] MK-5475 and its metabolites excreted in urine derived from urine collections at each sampling interval	At designated time points (Up to ~ 23 days)
Percentage Excreted in Urine (feu)	Percentage of [14C]MK-5475 and its metabolites excreted in urine derived from urine collections at each sampling interval.	At designated time points (Up to ~ 23 days)
Cumulative feu	Cumulative percentage of [14C]MK-5475 and its metabolites excreted in urine derived from urine collections at each sampling interval.	At designated time points (Up to ~ 23 days)
Amount Excreted in Feces (Aef)	Amount of [14C]MK-5475 and its metabolites excreted in feces derived from feces collections at each sampling interval.	At designated time points (Up to ~ 23 days)
Cumulative Aef	Cumulative amount of [14C]MK-5475 and its metabolites excreted in feces derived from feces collections at each sampling interval.	At designated time points (Up to ~ 23 days)
Cumulative Fef	Cumulative percentage of [14C]MK-5475 and its metabolites excreted in feces derived from feces collections at each sampling interval.	At designated time points (Up to ~ 23 days)
AUC0-t	Area under concentration time curve (AUC) from time zero to the last quantifiable concentration derived from the whole blood and plasma concentration-time profiles following IV administration of [14C]MK-5475.	At designated time points (Up to ~ 23 days)
AUC0-infinity	AUC from time zero extrapolated to infinity derived from the whole blood and plasma concentration-time profiles following IV administration of [14C]MK-5475.	At designated time points (Up to ~ 23 days)
Maximum Plasma Concentration (Cmax)	Cmax is the measure of the maximum amount of [14C]MK-5475 in the plasma after the dose is given.	At designated time points (Up to ~ 23 days)
Half-life t1/2	T1/2 is the time required for [14C]MK-5475 concentration in the plasma to decrease by 50%.	At designated time points (Up to ~ 23 days)
Time to Maximum Plasma Concentration (Tmax),	Tmax is a measure of the time to reach the maximum concentration in the plasma after the [14C]MK-5475 dose.	At designated time points (Up to ~ 23 days)
Apparent Total Clearance (CL; MK-5475 only)	CL is defined as apparent total clearance of [14C]MK-5475 from plasma after IV administration	At designated time points (Up to ~ 23 days)
Apparent Volume of Distribution (Vz; MK-5475 only)	Vz is defined as apparent volume of distribution of [14C]MK-5475 during terminal phase after IV administration.	At designated time points (Up to ~ 23 days)
AUC0-infinity Plasma [14C]MK-5475/Total Radioactivity Ratio	AUC time zero to infinity (0-∞) of [14C]MK-5475 in plasma/AUC0-∞ of total radioactivity in plasma.	At designated time points (Up to ~ 23 days)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants Who Experience an Adverse Event (AE)	An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants who experience an AE will be reported.	Up to ~ 30 days
Number of Participants Who Discontinue Study Due to an AE	An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. The number of participants who discontinue study due to an AE will be reported.	Up to ~ 30 days

Collaborators and Investigators

• Sponsor: Merck Sharp & Dohme LLC
• Investigators: Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

General Publications

• Menzel K, Liang Y, Chen B, Li D, Cislak D, Bajwa EK. An Intravenous Study with the Radiolabeled sGC Stimulator Frespaciguat to Assess PK, Metabolism, and Mass Balance. J Clin Pharmacol. 2025 Jun 19. doi: 10.1002/jcph.70066. Online ahead of print.

Helpful Links

• Merck Clinical Trials Information

Study record dates

Study Major Dates

• Study Start (Actual): August 15, 2022
• Primary Completion (Actual): September 30, 2022
• Study Completion (Actual): October 25, 2022

Study Registration Dates

• First Submitted: January 10, 2025
• First Submitted That Met QC Criteria: January 10, 2025
• First Posted (Actual): January 16, 2025

Study Record Updates

• Last Update Posted (Estimated): October 29, 2025
• Last Update Submitted That Met QC Criteria: October 27, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: 5475-011; MK-5475-011 (Other Identifier: MSD)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: http://engagezone.msd.com/doc/ProcedureAccessClinicalTrialData.pdf

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No