A Clinical Study of Belzutifan (MK-6482) Alone or With Phenytoin in Healthy Participants (CA46602/MK-6482-035)

June 12, 2025 updated by: Merck Sharp & Dohme LLC

An Open-Label, Phase 1 Study to Characterize the Effects of Phenytoin on the Pharmacokinetics of Belzutifan in Healthy Adult Participants

Researchers designed belzutifan, the study medicine, to treat certain kinds of cancer.

The goal of this study is to learn what happens to belzutifan in a healthy person's body over time when taken, by mouth, as a tablet. Researchers will learn what happens when belzutifan is taken alone and when it is taken after several days of treatment with phenytoin.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

14

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Arizona
      • Tempe, Arizona, United States, 85283
        • Celerion, Inc. ( Site 0001)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

The key inclusion criteria include but are not limited to the following:

  • Healthy, adult, male (vasectomized or surgically sterilized) or female (of non-childbearing potential)
  • Has a body mass index (BMI) ≥ 18.0 and ≤ 32.0 kg/m2

Exclusion Criteria:

The key exclusion criteria include but are not limited to the following:

  • Has a history of any illness that, in the opinion of the PI or designee, might confound the results of the study or poses an additional risk to the participant by their participation in the study
  • History or presence of: Seizure (excluding simple febrile seizure), epilepsy, severe head injury, multiple sclerosis, or other known neurological conditions which the PI considers to be clinically significant; Hypersensitivity reaction to anticonvulsant therapy (including phenytoin, primidone, and phenobarbital); Depression, unusual changes in mood or behavior or suicidal thoughts and behavior; Hepatic porphyria (e.g., acute intermittent porphyria, variegate porphyria, porphyria cutanea tarda)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Belzutifan + Phenytoin
Participants receive belzutifan during study Period 1, followed by a washout period, then they receive belzutifan and phenytoin during study Period 2.
Drug: Belzutifan
Oral administration
Other Names:
  • MK-6482
  • PT2977
  • Welireg™
Drug: Phenytoin
Oral administration
Other Names:
  • Phenytoin sodium

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Area Under the Concentration-Time Curve from Time 0 to Infinity (AUC0-Inf) of Belzutifan
Time Frame: Predose and at designated timepoints up to 120 hours postdose
Blood samples will be collected to determine the AUC0-inf of belzutifan.
Predose and at designated timepoints up to 120 hours postdose

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Participants Who Experience an Adverse Event (AE)
Time Frame: Up to approximately 36 days
An AE is any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants who experience an AE will be reported.
Up to approximately 36 days
Number of Participants Who Discontinue Study Drug Due to an AE
Time Frame: Up to approximately 22 days
An AE is any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants who discontinue study due to an AE will be reported.
Up to approximately 22 days
Area Under the Concentration-Time Curve from Time 0 to Last (AUC0-last) of Belzutifan in Plasma
Time Frame: Predose and at designated timepoints up to 120 hours postdose
Blood samples will be collected to determine the AUC0-last of belzutifan.
Predose and at designated timepoints up to 120 hours postdose
Area Under the Concentration-Time Curve from Time 0 to 24 Hours (AUC0-24) of Belzutifan in Plasma
Time Frame: Predose and at designated timepoints up to 24 hours postdose
Blood samples will be collected to determine the AUC0-24 of belzutifan.
Predose and at designated timepoints up to 24 hours postdose
Maximum Plasma Concentration (Cmax) of Belzutifan in Plasma
Time Frame: Predose and at designated timepoints up to 120 hours postdose
Blood samples will be collected to determine the Cmax of belzutifan.
Predose and at designated timepoints up to 120 hours postdose
Plasma Concentration 24 Hours Postdose (C24) of Belzutifan in Plasma
Time Frame: 24 hours postdose
Blood samples will be collected to determine the C24 of belzutifan.
24 hours postdose
Time to Maximum Plasma Concentration (Tmax) of Belzutifan in Plasma
Time Frame: Predose and at designated timepoints up to 120 hours postdose
Blood samples will be collected to determine the Tmax of belzutifan.
Predose and at designated timepoints up to 120 hours postdose
Apparent Terminal Half-life (t1/2) of Belzutifan in Plasma
Time Frame: Predose and at designated timepoints up to 120 hours postdose
Blood samples will be collected to determine the t1/2 of belzutifan.
Predose and at designated timepoints up to 120 hours postdose
Apparent Clearance (CL/F) of Belzutifan in Plasma
Time Frame: Predose and at designated timepoints up to 120 hours postdose
Blood samples will be collected to determine the CL/F of belzutifan.
Predose and at designated timepoints up to 120 hours postdose
Apparent Volume of Distribution during terminal phase (Vz/F) of Belzutifan in Plasma
Time Frame: Predose and at designated timepoints up to 120 hours postdose
Blood samples will be collected to determine the Vz/F of belzutifan.
Predose and at designated timepoints up to 120 hours postdose

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Merck Sharp & Dohme LLC

Investigators

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

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 28, 2025

Primary Completion (Actual)

May 8, 2025

Study Completion (Actual)

May 27, 2025

Study Registration Dates

First Submitted

March 25, 2025

First Submitted That Met QC Criteria

March 25, 2025

First Posted (Actual)

April 1, 2025

Study Record Updates

Last Update Posted (Actual)

June 13, 2025

Last Update Submitted That Met QC Criteria

June 12, 2025

Last Verified

June 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 6482-035
  • CA46602 (Other Identifier: Celerion)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

https://trialstransparency.msdclinicaltrials.com/pdf/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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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