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MK-6598

Phase 1

Advanced or Metastatic Solid Tumors | Small molecule | Oncology |Merck & Company, Inc.|Last Updated: Jul 15, 2026

Success Probability

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Market & Valuation

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Trial Design

CONTROLLED
Total Trials1
Total Enrollment39

FDA Designations

No designations recorded

Clinical trial landscape

MK-6598 · 1 trial · 1 indication

Phase 1 1
NCT05594043A Study of MK-6598 as Monotherapy and in Combination With Pembrolizumab (MK-3475) in Advanced Solid Tumors (MK-6598-001)Advanced or Metastatic Solid Tumors
COMPLETED39 Analytics
PHASE1COMPLETED
A Study of MK-6598 as Monotherapy and in Combination With Pembrolizumab (MK-3475) in Advanced Solid Tumors (MK-6598-001)
Advanced or Metastatic Solid TumorsUnlock trial analytics

Study Endpoints

Primary Endpoints

Number of Participants With a Dose-Limiting Toxicity (DLT) Graded Using National Cancer Institute Common Terminology Criteria for Adverse Events (AEs) Version 5.0
Up to approximately 21 days

DLT is defined as any of the following toxicities, unless assessed by investigator as 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 lasting ≥7 days; Gr 4 anemia of any duration; Nonhematologic AE Gr ≥3 in severity, with exceptions; Any Gr 3/4 nonhematologic lab abnormality if it requires clinically significant medical intervention, leads to hospitalization, persists for \>72 hours, or results in certain drug-induced liver injuries, with some exceptions; Gr 3 or 4 febrile neutropenia; \>2 week delay in initiating Cycle 2 due to treatment-related toxicity; Treatment-related toxicity resulting in study treatment discontinuation during Cycle 1 (C1), 1 cycle = 21 days; Missing \>25% of MK-6598 doses due to treatment-related AE during C1; Gr 5 toxicity.

Number of Participants Who Experienced At Least One AE
Up to approximately 24 months

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.

Number of Participants Who Discontinue Study Treatment Due to an AE
Up to approximately 24 months

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 Endpoints

Area Under the Curve From Time 0 to Last Quantifiable Sample (AUC0-last) of MK-6598
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.
Minimum Serum Concentration (Cmin) of MK-6598
Days 8 and 15 of Cycle 1: predose, postdose at 30 min, 45 min, 60 min, 2 hrs, 6 hrs. Days 2 and 9 of Cycle 1: predose.
Maximum Serum Concentration (Cmax) of MK-6598
Days 1, 8, and 15 of Cycle 1: predose, postdose at 30 min, 45 min, 60 min, 2 hrs, 6 hrs. Days 2 and 9 of Cycle 1: predose.
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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
MK-6598EXPERIMENTALParticipants received MK-6598 daily (QD) between 50-500 mg for up to a total of 35 cycles (up to approximately 24 months). Participants were allowed at the investigator's discretion and after consultation with the Sponsor, to cross over to receive combination treatment of MK-6598 and Pembrolizumab
MK-6598 + PembrolizumabEXPERIMENTALQD between 50-250 mg, plus pembrolizumab 200 mg once every 21-day cycle for up to 35 cycles (up to approximately 24 months).

Interventions

NameTypeDescription
MK-6598DRUGOral tablet
PembrolizumabBIOLOGICALIntravenous (IV) infusion
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites6

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 a...

Countries:United StatesCanadaSwitzerland
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Competitive Landscape -Other Solid Tumors 9 trials (matched to "Advanced or Metastatic Solid Tumors")

Recent Changes (Last 90 Days)

MEDIUMAug 15, 2026NCT05594043TRIAL_REMOVED: changed
MEDIUMAug 15, 2026NCT05594043TRIAL_REMOVED: changed
MEDIUMAug 15, 2026NCT05594043TRIAL_REMOVED: changed

Frequently asked questions about MK-6598

What is MK-6598 used for?

MK-6598 is an investigational small molecule being studied for the treatment of advanced or metastatic solid tumors. It is being evaluated as a monotherapy and in combination with pembrolizumab (MK-3475) in patients with advanced solid tumors.

Who makes MK-6598?

MK-6598 is being developed by Merck & Company, Inc., which trades on the New York Stock Exchange under the ticker MRK. The company is conducting clinical trials to evaluate the drug's safety and efficacy in advanced solid tumors.

What phase is MK-6598 in?

MK-6598 is in Phase 1 clinical development. It is an investigational drug and has not been approved by regulatory authorities. The Phase 1 trial has been completed, and the drug remains under clinical investigation.

What clinical trials is MK-6598 in?

MK-6598 has been studied in a Phase 1 trial with the identifier NCT05594043. This trial evaluated MK-6598 as monotherapy and in combination with pembrolizumab in patients with advanced or metastatic solid tumors. The trial enrolled 39 participants and has been completed.

Is MK-6598 the same as pembrolizumab?

No, MK-6598 is not the same as pembrolizumab. MK-6598 is a separate investigational small molecule being studied by Merck. Pembrolizumab, also known as MK-3475, is an approved immunotherapy that is being tested in combination with MK-6598 in the clinical trial.