A Study of Bomedemstat (IMG-7289/MK-3543) in Participants With Polycythemia Vera (IMG-7289-CTP-203/MK-3543-004)

A Phase 2 Multi-Center, Open Label Study to Assess the Safety, Efficacy, Pharmacokinetics and Pharmacodynamics of Bomedemstat in Patients With Polycythemia Vera (PV)

This study will evaluate the safety, efficacy, pharmacokinetics (PK), and pharmacodynamics of the orally administered lysine-specific demethylase 1 (LSD1) inhibitor bomedemstat, in participants with polycythemia vera (PV). At Week 36 of dosing, participants will be assessed for eligibility to receive additional treatment through Week 52. Participants deriving clinical benefit and safely tolerating bomedemstat will qualify for continued treatment at the Investigator's discretion.

Study Overview

• Status: Completed
• Conditions: Polycythemia Vera
• Intervention / Treatment: Drug: Bomedemstat

Detailed Description

With Amendment 3, after all ongoing participants have reached 52 weeks of treatment, eligible participants may transition to a bomedemstat extension study if available. With Amendment 4, all secondary PK and participant reported outcome measures were designated as exploratory.

Per protocol, participants who derived clinical benefit (no progressive disease) and safely tolerated drug may have qualified for enrollment into the bomedemstat extension study (NCT06351631).

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Phase 2

Contacts and Locations

Study Locations

• Australia
  • Queensland
    • Sunshine Coast, Queensland, Australia, 4556
      • Sunshine Coast Hematology and Oncology Clinic (Site 0506)
  • Victoria
    • Clayton, Victoria, Australia, 3168
      • Monash Medical Centre ( Site 0006)
  • Western Australia
    • Perth, Western Australia, Australia, 6000
      • Royal Perth Hospital ( Site 0504)
• United Kingdom
  • England
    • Gloucester, England, United Kingdom, GL1 3NN
      • Gloucestershire Royal Hospital ( Site 0205)
  • Great Britain
    • Lincoln, Great Britain, United Kingdom, LN2 5QY
      • United Lincolnshire Hospitals NHS Trust ( Site 0204)
    • London, Great Britain, United Kingdom, W12 0HS
      • Imperial College London ( Site 0025)
  • Lincolnshire
    • Boston, Lincolnshire, United Kingdom, PE21 9QS
      • Boston Pilgrim Hospital ( Site 0207)
  • London, City of
    • London, London, City of, United Kingdom, SE1 9RT
      • Guys and St Thomas NHS Foundation Trust - Guys Hospital ( Site 0020)
  • Wales
    • Newport, Wales, United Kingdom, NP9 2UB
      • Royal Gwent Hospital ( Site 0201)
• United States
  • Florida
    • Plantation, Florida, United States, 33322
      • BRCR Global ( Site 0120)
  • Illinois
    • Skokie, Illinois, United States, 60076-1264
      • Hematology Oncology of the North Shore ( Site 0104)
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • University of Michigan Comprehensive Cancer Center ( Site 0008)
  • Nevada
    • Las Vegas, Nevada, United States, 89128
      • Comprehensive Cancer Centers of Nevada - Peak ( Site 0118)
  • North Carolina
    • Durham, North Carolina, United States, 27705
      • Duke University Medical Center ( Site 0016)
  • Ohio
    • Columbus, Ohio, United States, 43203
      • Ohio State University Comprehensive Cancer Center ( Site 0103)
  • Oregon
    • Portland, Oregon, United States, 97239-4503
      • OHSU Knight Cardiovascular Institute Cardiology Clinic - South Waterfront ( Site 0102)
  • Utah
    • Salt Lake City, Utah, United States, 84112
      • Huntsman Cancer Hospital at the University of Utah ( Site 0119)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Has a diagnosis of Polycythemia Vera per World Health Organization (WHO) diagnostic criteria for myeloproliferative neoplasms
• Has a bone marrow fibrosis score of Grade 0 or Grade 1
• Has failed at least one standard cytoreductive therapy to lower hematocrit
• Has a life expectancy >36 weeks
• Has discontinued prior cytoreductive therapy for 2 weeks (4 weeks for interferon) prior to study drug initiation

Exclusion Criteria:

• Has an Eastern Cooperative Oncology Group (ECOG) performance status of 3 or greater
• Has unresolved treatment related toxicities from prior therapies (unless resolved to ≤ Grade 1)
• Has an uncontrolled active infection
• Has a known human immunodeficiency virus (HIV) infection or active Hepatitis A, Hepatitis B or Hepatitis C virus infection
• Has evidence of increased risk of bleeding, including known bleeding disorders
• Is pregnant or lactating

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Bomedemstat; Participants will receive bomedemstat daily for 36 weeks and may qualify for additional treatment through Week 52 if deriving clinical benefit.	Drug: Bomedemstat; Oral capsule; Other Names: IMG-7289; MK-3543

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Adverse Events (AEs)	An AE was defined as 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 with one or more AEs are reported.	Up to approximately 52 weeks
Number of Participants Who Discontinued Study Intervention Due to AEs	An AE was defined as 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 discontinued study intervention due to an AE are reported.	Up to approximately 52 weeks
Percentage of Participants With Sustained 12-week Reduction of Hematocrit (Hct) to <45% Without Concomitant Phlebotomy by Week 36	Hematocrit (Hct) was analyzed by taking blood samples from participants at designated time points during the study. Participants were considered responders if they achieved a sustained reduction of Hct to <45% for 12 weeks (84 calendar days) by Week 36 AND there was no concomitant phlebotomy performed during the sustained reduction. Baseline data was defined as the data most recently collected prior to the first dose. A Clopper-Pearson (exact binomial) two-sided 95% confidence interval for the percentage of responders was presented. The percentage of participants who achieved a sustained 12-week reduction of Hct to <45% without concomitant phlebotomy at Week 36 are reported.	Up to approximately 36 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Duration of Reduction of Hematocrit (Hct) to <45% Without Phlebotomy	Total response duration was defined as the summation of all Hct <45% response durations, where an individual response duration starts at the timepoint where the Hct <45% and ends at the first subsequent occurrence of phlebotomy or Hct >=45%. Hct was analyzed by taking blood samples from participants at designated time points during the study. Duration of reduction of Hct to <45% without phlebotomy was presented.	Up to approximately 22 months
Percentage of Participants With Platelet Count ≤ 450 x 10^9/L by Week 36	Platelet count was analyzed by taking blood samples from participants at designated time points during the study. Participants who enter the study with platelet counts ≤450 X 10^9/L must achieve an additional on-study platelet count ≤450 X 10^9/L to be considered responders. A Clopper-Pearson (exact binomial) two-sided 95% confidence interval for the percentage of responders is presented. Baseline data was defined as the data most recently collected prior to the first dose. The percentage of participants who have a platelet count ≤450 X 10^9/L by week 36 are reported.	Up to approximately 36 weeks
Duration of Platelet Count ≤ 450 x 10^9/L	Total response duration was defined as the summation of all platelet ≤450 x 10^9/L response durations, where an individual response duration starts at the timepoint where platelet count ≤450 x 10^9/L and ends at the first subsequent occurrence of platelet >450 x 10^9/L. Platelet counts were analyzed by taking blood samples from participants at designated time points during the study. The duration of platelet count ≤450 X 10^9/L in participants are reported.	Up to approximately 22 months
Percentage of Participants With White Blood Cell (WBC) Count <10 x 10^9/L by Week 36	WBC count was analyzed by taking blood samples from participants at designated time points during the study. Participants who enter the study with WBC counts <10 X 10^9/L must achieve an additional on-study WBC count <10 X 10^9/L to be considered responders. A Clopper-Pearson (exact binomial) two-sided 95% confidence interval for the percentage of responders is presented. Baseline data was defined as the data most recently collected prior to the first dose. The percentage of participants who have a WBC count <10 X 10^9/L week 36 are reported.	Up to approximately 36 weeks
Duration of White Blood Cell (WBC) Count <10 x 10^9/L	Total response duration was defined as the summation of all WBC <10 x 10^9/L response durations, where an individual response duration starts at the timepoint when WBC <10 x 10^9/L and ends at the first subsequent occurrence of WBC ≥ 10 x 10^9/L. WBC count was analyzed by taking blood samples from participants at designated time points during the study. The duration of WBC count <10 X 10^9/L in participants are reported.	Up to approximately 22 months
Number of Participants With Thrombotic Events	Thrombotic events are defined as: new or recurrent acute myocardial infarction; unstable angina; stroke; transient ischemic attack (TIA); deep venous thrombosis (DVT); pulmonary embolism (PE); thrombotic digital ischemia; other thrombotic events such as peripheral limb ischemia or Budd-Chiari syndrome that are assessed to be due to underlying polycythemia vera (PV); other vascular occlusive events such as symptoms of cardiac, abdominal or peripheral limb ischemia supported by objective evidence of vessel disease and/or ischemia. Baseline data was defined as the data most recently collected prior to the first dose. The number of participants with thrombotic events are reported.	Up to approximately 22 months
Number of Participants With Major Hemorrhagic Events	Hemorrhagic events were defined as: Major Bleeding (MB) Events such as fatal bleeding, and/or symptomatic bleeding in a critical area or organ such as intracranial, intraspinal, intraocular, retroperitoneal, intra-articular or pericardial, or intramuscular with compartment syndrome, and/or bleeding causing a fall in hemoglobin level of 2 g/dL or more, or leading to transfusion of 2 or more units of whole blood or red cells; Clinically Relevant Non-Major Bleeding (CRNMB) Events Leading to hospitalization or increased level of care or clinically important, prompting a face-to-face medical evaluation. Baseline data was defined as the data most recently collected prior to the first dose. The number of participants with major hemorrhagic events are reported.	Up to approximately 22 months
Number of Participants With an Enlarged Spleen at Baseline Who Had a Reduction in Splenic Volume by 36 Weeks	Spleen volume was measured by magnetic resonance imaging (MRI) (or computerized tomography [CT] if participant is not a candidate for MRI) of the abdomen according to standard procedures. Baseline data was defined as the data most recently collected prior to the first dose. The number of participants with an enlarged spleen at baseline (volume >450 cm^3) who achieved any reduction in spleen volume by Week 36 are reported.	Up to approximately 36 weeks
Number of Participants With Progressive Disease (PD)	PD was defined as the worsening of Polycythemia Vera (PV) to post-PV myelofibrosis, myelodysplastic syndrome or transformation to acute myeloid leukemia. Baseline data was defined as the data most recently collected prior to the first dose. The number of participants with PD are reported.	Up to approximately 52 weeks

Collaborators and Investigators

• Sponsor: Imago BioSciences, Inc., a subsidiary of Merck & Co., Inc., (Rahway, New Jersey USA)
• Investigators: Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

Helpful Links

• Merck Clinical Trials Information
• Plain Language Summary

Study record dates

Study Major Dates

• Study Start (Actual): September 7, 2023
• Primary Completion (Actual): March 24, 2025
• Study Completion (Actual): July 10, 2025

Study Registration Dates

• First Submitted: September 20, 2022
• First Submitted That Met QC Criteria: September 26, 2022
• First Posted (Actual): September 28, 2022

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: April 16, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: polycythemia vera; bomedemstat
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Hematologic Diseases; Bone Marrow Diseases; Myeloproliferative Disorders; Bone Marrow Neoplasms; Hematologic Neoplasms; Hemic and Lymphatic Diseases; Polycythemia Vera; bomedemstat
• Other Study ID Numbers: 3543-004; IMG-7289-CTP-203 (Other Identifier: Imagobio ID); MK-3543-004 (Other Identifier: MSD); 2022-002262-32 (EudraCT Number)

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