A Study of the Effect of Itraconazole and Phenytoin on Calderasib (MK-1084) in Healthy Adults (MK-1084-008)

February 9, 2026 updated by: Merck Sharp & Dohme LLC

A Two-Part Study to Evaluate the Effects of Multiple Doses of Itraconazole and Multiple Doses of Phenytoin on the Single-Dose Pharmacokinetics of MK-1084 in Healthy Adult Participants

The goal of this study is to learn what happens to calderasib in a healthy person's body over time, called a pharmacokinetic (PK) study. Researchers want to compare the amount of calderasib when it is taken as a single dose; with multiple doses of itraconazole, or with multiple doses of phenytoin.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

28

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
    • Nebraska
      • Lincoln, Nebraska, United States, 68502
        • Celerion (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 main inclusion criteria include but are not limited to the following:

- Has body mass index (BMI) ≥18 kg/m^2 and ≤32 kg/m^2

Exclusion Criteria:

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

  • History of cancer (malignancy)
  • Positive results for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV)

Part 1 Only:

- History or presence of ventricular dysfunction or risk factors for Torsades de Pointes (e.g., heart failure, cardiomyopathy, family history of Long QT Syndrome)

Pat 2 Only:

- History of seizure (excluding simple febrile seizure), epilepsy, severe head injury, multiple sclerosis, or other known neurological conditions

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: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Part 1: Calderasib + Itraconazole
Part 1: In Period 1 participants receive a single dose of calderasib on Day 1 under fasting conditions. In Period 2 participants receive itraconazole once daily (QD) for 7 consecutive days (Day 1 - Day 7), plus a single dose of calderasib administered approximately 2 hours after itraconazole dosing on Day 5. There will be a washout of at least 7 days between dosing in Period 1 and the first dose in Period 2.
Drug: Itraconazole
Oral solution
Drug: Calderasib
Oral Tablet
Other Names:
  • MK-1084
Experimental: Part 2: Calderasib + Phenytoin
Part 2: In Period 1 participants receive a single dose of calderasib on Day 1 under fasting conditions. In Period 2 participants receive phenytoin three times daily (TID) for 14 consecutive days (Day 1 - Day 14), plus a single dose of calderasib co-administered on the morning of Day 13. There will be a washout of at least 7 days between dosing in Period 1 and the first dose in Period 2.
Drug: Phenytoin
Oral capsule (extended)
Drug: Calderasib
Oral Tablet
Other Names:
  • MK-1084

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 After Single Dosing (AUC0-Inf) of Calderasib
Time Frame: Pre-dose and at designated time points up to 72 hours post dose
Blood samples will be collected to determine the AUC0-Inf of calderasib.
Pre-dose and at designated time points up to 72 hours post dose

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Participants Who Experience an Adverse Event (AE)
Time Frame: Up to approximately 41 days
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 approximately 41 days
Number of Participants Who Discontinue Study Treatment Due to an AE
Time Frame: Up to approximately 25 days
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 treatment due to an AE will be reported.
Up to approximately 25 days
Area Under the Concentration-Time Curve from Time 0 to Last Quantifiable Sample (AUC0-last) of Calderasib
Time Frame: Pre-dose and at designated time points up to 72 hours post dose
Blood samples will be collected to determine the AUC0-last of calderasib.
Pre-dose and at designated time points up to 72 hours post dose
Area Under the Concentration-Time Curve from Time 0 to 24 hours (AUC0-24) of Calderasib
Time Frame: Pre-dose and at designated time points up to 24 hours post dose
Blood samples will be collected to determine the AUC0-24 of calderasib.
Pre-dose and at designated time points up to 24 hours post dose
Maximum Plasma Concentration (Cmax) of Calderasib
Time Frame: Pre-dose and at designated time points up to 72 hours post dose
Blood samples will be collected to determine the Cmax of calderasib.
Pre-dose and at designated time points up to 72 hours post dose
Plasma Concentration at 24 Hours (C24) of Calderasib
Time Frame: Pre-dose and at designated time points up to 24 hours post dose
Blood samples will be collected to determine the C24 of calderasib.
Pre-dose and at designated time points up to 24 hours post dose
Time to Maximum Plasma Concentration (Tmax) of Calderasib
Time Frame: Pre-dose and at designated time points up to 72 hours post dose
Blood samples will be collected to determine the Tmax of calderasib.
Pre-dose and at designated time points up to 72 hours post dose
Apparent Terminal Half-life (t1/2) of Calderasib
Time Frame: Pre-dose and at designated time points up to 72 hours post dose
Blood samples will be collected to determine the t1/2 of calderasib.
Pre-dose and at designated time points up to 72 hours post dose
Apparent Clearance (CL/F) of Calderasib
Time Frame: Pre-dose and at designated time points up to 72 hours post dose
Blood samples will be collected to determine the CL/F of calderasib.
Pre-dose and at designated time points up to 72 hours post dose
Apparent volume of distribution during terminal phase (Vz/F) of Calderasib
Time Frame: Pre-dose and at designated time points up to 72 hours post dose
Blood samples will be collected to determine the Vz/F of calderasib.
Pre-dose and at designated time points up to 72 hours post dose

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)

May 20, 2024

Primary Completion (Actual)

July 30, 2024

Study Completion (Actual)

July 30, 2024

Study Registration Dates

First Submitted

December 2, 2024

First Submitted That Met QC Criteria

December 2, 2024

First Posted (Actual)

December 6, 2024

Study Record Updates

Last Update Posted (Actual)

February 11, 2026

Last Update Submitted That Met QC Criteria

February 9, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1084-008
  • MK-1084-008 (Other Identifier: MSD)
  • CA43207 (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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