HealthyPhase 1NCT06903715
A Clinical Study of Belzutifan (MK-6482) Alone or With Phenytoin in Healthy Participants (CA46602/MK-6482-035)
A Phase 1 study testing Belzutifan and Phenytoin in people with Healthy, run by Merck Sharp & Dohme LLC at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- Belzutifan and Phenytoin
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 siteUnited States
- Study dates
- 28 Mar 2025to 27 May 2025
- Phase
- Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
Who cannot join
- 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)
Trial locations and contacts
1 site in 1 country.
About this study
Official title: 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.
- Conditions
- Healthy
- Being tested
- Belzutifan, Phenytoin
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
BelzutifanDrug
Also called MK-6482, PT2977, Welireg™
Oral administration
PhenytoinDrug
Also called Phenytoin sodium
Oral administration
| Study group | Role | What they receive |
|---|---|---|
| Belzutifan + Phenytoin | Experimental | Participants receive belzutifan during study Period 1, followed by a washout period, then they receive belzutifan and phenytoin during study Period 2. Receives: Drug: Belzutifan; Drug: Phenytoin |
What is being measured
The primary outcome is the main question the study is designed to answer.
Area Under the Concentration-Time Curve from Time 0 to Infinity (AUC0-Inf) of Belzutifan
Blood samples will be collected to determine the AUC0-inf of belzutifan.
Measured: Predose and at designated timepoints up to 120 hours postdose
Secondary outcomes (10)
Number of Participants Who Experience an Adverse Event (AE)
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.
Measured: Up to approximately 36 days
Number of Participants Who Discontinue Study Drug Due to an AE
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.
Measured: Up to approximately 22 days
Area Under the Concentration-Time Curve from Time 0 to Last (AUC0-last) of Belzutifan in Plasma
Blood samples will be collected to determine the AUC0-last of belzutifan.
Measured: 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
Blood samples will be collected to determine the AUC0-24 of belzutifan.
Measured: Predose and at designated timepoints up to 24 hours postdose
Maximum Plasma Concentration (Cmax) of Belzutifan in Plasma
Blood samples will be collected to determine the Cmax of belzutifan.
Measured: Predose and at designated timepoints up to 120 hours postdose
Plasma Concentration 24 Hours Postdose (C24) of Belzutifan in Plasma
Blood samples will be collected to determine the C24 of belzutifan.
Measured: 24 hours postdose
Time to Maximum Plasma Concentration (Tmax) of Belzutifan in Plasma
Blood samples will be collected to determine the Tmax of belzutifan.
Measured: Predose and at designated timepoints up to 120 hours postdose
Apparent Terminal Half-life (t1/2) of Belzutifan in Plasma
Blood samples will be collected to determine the t1/2 of belzutifan.
Measured: Predose and at designated timepoints up to 120 hours postdose
Apparent Clearance (CL/F) of Belzutifan in Plasma
Blood samples will be collected to determine the CL/F of belzutifan.
Measured: Predose and at designated timepoints up to 120 hours postdose
Apparent Volume of Distribution during terminal phase (Vz/F) of Belzutifan in Plasma
Blood samples will be collected to determine the Vz/F of belzutifan.
Measured: Predose and at designated timepoints up to 120 hours postdose
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Apr 2025
- Study start28 Mar 2025
- Primary completion8 May 2025
- Study completion27 May 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by Merck Sharp & Dohme LLCThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- Merck Sharp & Dohme LLC
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Merck Sharp & Dohme LLC
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06903715
- Sponsor's protocol ID
- 6482-035
- Other IDs
- CA46602
- Status last verified
- Jun 2025
- First submitted
- 25 Mar 2025
- Last updated
- 13 Jun 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Study at a glance
From the registry record, last updated by the sponsor on 13 Jun 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-Label, Phase 1 Study to Characterize the Effects of Phenytoin on the Pharmacokinetics of Belzutifan in Healthy Adult Participants
- ClinicalTrials.gov ID
- NCT06903715
- Acronym / sponsor ID
- 6482-035
- Conditions
- Healthy
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 14 participants (actual)
- Lead sponsor
- Merck Sharp & Dohme LLCIndustry (pharma, biotech, devices)
- Study start
- 28 Mar 2025 (actual)
- Primary completion
- 8 May 2025 (actual)
- Study completion
- 27 May 2025 (actual)
- First posted
- 1 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Belzutifan + Phenytoin | Experimental | Drug: Belzutifan, Drug: PhenytoinParticipants receive belzutifan during study Period 1, followed by a washout period, then they receive belzutifan and phenytoin during study Period 2. |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- 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
Key exclusion criteria (3 listed)
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| BelzutifanAlso: MK-6482, PT2977, Welireg™Oral administration | Drug | Belzutifan + Phenytoin |
| PhenytoinAlso: Phenytoin sodiumOral administration | Drug | Belzutifan + Phenytoin |
Primary outcome
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.
10 secondary outcomes
Number of Participants Who Experience an Adverse Event (AE)
Time frame: Up to approximately 36 days
Number of Participants Who Discontinue Study Drug Due to an AE
Time frame: 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
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
Maximum Plasma Concentration (Cmax) of Belzutifan in Plasma
Time frame: 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
Time to Maximum Plasma Concentration (Tmax) of Belzutifan in Plasma
Time frame: 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
Apparent Clearance (CL/F) of Belzutifan in Plasma
Time frame: 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
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Jun 2025.
- Merck Clinical Trials InformationLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Related trials for Healthy
Recruiting
THE EFFECTS OF GAME-BASED EXERCISE PROGRAMS
Physical Activity, Body Image
Not yet recruitingPhase 1
A Phase I Study of GLR2053 Tablets in Chinese Healthy Adult Participants
Atopic Dermatitis
Recruiting
Colon-delivered Riboflavin and Gut Microbiota Composition
Microbiome Dysbiosis, Gut Health
Not yet recruiting
Neuroergonomic Analysis of a Brain-Computer Interface Device (BCI)
Healthy Volunteers - Male and Female
RecruitingPhase 1
First-in-Human Trial to Assess REGN20423 in Healthy Adult Participants and Adult Participants With Atopic Dermatitis
Healthy Volunteer, Atopic Dermatitis
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Medical Director study director
Merck Sharp & Dohme LLC
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Belzutifan and Phenytoin in people with Healthy, run by Merck Sharp & Dohme LLC at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 13 Jun 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Jun 2025; AzTrials last refreshed its copy on 7 Nov 2026.