A Study of MK-6598 as Monotherapy and in Combination With... | NCT05594043

ID	Type	Description	Link
MK-6598-001	Other Identifier	MSD

Status Module

Label	Type	Description	Intervention Names
MK-6598	Experimental	Participants will receive MK-6598 daily (QD) at escalating dose levels from 50-500 mg for up to a total of 35 cycles (up to approximately 24 months).	Drug: MK-6598
MK-6598 + Pembrolizumab	Experimental	Participants will receive MK-6598 QD at escalating dose levels from 50-500, plus pembrolizumab 200 mg once every 21-day cycle for up to 35 cycles (up to approximately 24 months).	Drug: MK-6598 Biological: Pembrolizumab

Name	Type	Description	Arm Group Labels	Other Names
MK-6598	Drug	Oral tablet	MK-6598 MK-6598 + Pembrolizumab

Outcomes Module

Primary Outcomes

Measure	Description	Time Frame
Number of Participants with a Dose-Limiting Toxicity (DLT) Graded Using National Cancer Institute Common Terminology Criteria for Adverse Events (AEs) Version 5.0	DLT is defined as any of the following toxicities, unless assessed by the investigator to be clearly due to the underlying disease or extraneous causes: Grade (Gr) 4 nonhematologic toxicity (not laboratory); Gr 4 hematologic toxicity lasting ≥7 days, except thrombocytopenia; Gr 4 thrombocytopenia of any duration; Gr 3 thrombocytopenia associated with clinically significant bleeding; Gr 4 anemia regardless of duration; Nonhematologic AE Gr ≥3 in severity, with exceptions; Any Gr 3 or 4 nonhematologic lab abnormality if clinically significant medical intervention is required, or if leads to hospitalization, persists for >72 hours or results in drug-induced liver injury with exceptions; Gr 3 or 4 febrile neutropenia; Prolonged delay (>2 weeks) in initiating Cycle 2 due to treatment-related toxicity; Treatment-related toxicity resulting in study treatment discontinuation during Cycle 1 (C1); Missing >25% of MK-6598 doses as a result of treatment-related AE during C1; Gr 5 toxicity.	Up to approximately 21 days
Number of Participants Who Experience At Least One 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. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants who experienced an AE will be reported.	Up to approximately 27 months
Number of Participants Who Discontinue Study Treatment 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. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants who discontinued study treatment due to an AE will be reported.

Secondary Outcomes

Measure	Description	Time Frame
Area Under the Curve (AUC) of MK-6598	Blood samples collected pre-dose and at multiple timepoints post-dose will be used to determine AUC.	Days 1, 8, and 15 of Cycle 1: predose, postdose at 30 minutes (min), 45 min, 60 min, 2 hours (hrs), 6 hrs; Days 2 and 9 of Cycle 1: predose; Day 1 of Cycles 2, 5, 10, 15, 20, 25, 30, and 35: predose

Eligibility Module

Eligibility Criteria

Inclusion Criteria:

Has a histologically- or cytologically-confirmed advanced/metastatic solid tumor by pathology report and has received, or been intolerant to, all treatment known to confer clinical benefit.
Has measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 as assessed by the local site investigator/radiology.
Has one or more discrete malignant lesions that are amenable to a minimum of 2 separate biopsies.
Has a baseline tumor sample that can be submitted for analysis.
Human immunodeficiency virus (HIV)-infected participants must have well controlled HIV on antiretroviral therapy (ART).
A participant assigned male sex at birth who receives MK-6598 must agree to use contraception and should refrain from donating sperm during the specified period(s) of at least 102 days after study interventions.
A participant assigned female sex at birth is eligible to participate if not pregnant or breastfeeding and at least 1 of the following: not a participant of childbearing potential (POCBP) or a POCBP who agrees to follow the contraceptive guidance during the treatment period and for up to 120 days after study intervention.

Exclusion Criteria:

Received prior systemic anticancer therapy including investigational agents within 4 weeks before the first dose of study intervention or has not recovered to CTCAE Version 5.0 Grade 1 or better from any AEs that were due to cancer therapeutics administered more than 4 weeks earlier (this includes participants with previous immunomodulatory therapy with residual immune-related AEs).
Known additional malignancy that is progressing or has required active treatment within 2 years.
Clinically active central nervous system (CNS) metastases and/or carcinomatous meningitis.
A severe hypersensitivity (≥Grade 3) reaction to treatment with a monoclonal antibody/components of the study intervention.
Active infection requiring therapy.
History of interstitial lung disease.
History of (noninfectious) pneumonitis that required steroids or current pneumonitis.
Active autoimmune disease that has required systemic treatment in the past 2 years. Replacement therapy (eg, thyroxine, insulin, or physiologic corticosteroid) is allowed.
Has known hepatitis B or C infections or known to be positive for hepatitis B surface antigen (HBsAg)/hepatitis B virus (HBV) deoxyribonucleic acid (DNA) or hepatitis C antibody or ribonucleic acid (RNA).
Has a history or current evidence of any condition, therapy, laboratory abnormality, or other circumstance that might confound the results of the study or interfere with the participant's participation for the full duration of the study, such that it is not in the best interest of the participant to participate, in the opinion of the treating investigator.
Received prior radiotherapy within 2 weeks of start of study intervention, has radiation-related toxicities requiring corticosteroids, or had a history of radiation pneumonitis.
Has received a live or live-attenuated vaccine within 30 days before the first dose of study intervention. Administration of killed vaccines are allowed.
Has received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (eg, cytotoxic T-lymphocyte-associated protein 4 [CTLA-4], OX 40, CD137), and was discontinued from that treatment due to a ≥Grade 3 immune-related AE (irAE).
Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days before the start of study treatment.
Has had an allogeneic tissue/solid organ transplant in the last 5 years or has evidence of graft-versus-host disease.

Facility	Status	City	State	ZIP	Country	Contacts
Sanford Cancer Center ( Site 0300)		Sioux Falls	South Dakota	57104	United States
Princess Margaret Cancer Centre ( Site 0101)

Type	Date	Date Unknown
Release	May 11, 2026
Reset	Jun 5, 2026

Release Date	Unrelease Date	Unrelease Date Unknown	Reset Date	MCP Release Number
May 11, 2026			Jun 5, 2026
Jun 17, 2026