An Extension Study of Bomedemstat (IMG-7289/MK-3543) in Participants With Myeloproliferative Neoplasms (IMG-7289-CTP-202/MK-3543-005)

NCT05223920 | Completed Phase 2 Results DMC FDA Drug

• 4 other identifiers: IMG-7289-CTP-202MK-3543-005IMG-72892021-002452-37
• Study Type: interventional
• Target: 81
• Locations: 7 countries
• Sites: 19

Brief Summary

This is a multi-center, open-label extension study to assess the long-term safety and efficacy of bomedemstat administered orally once daily in participants with a Myeloproliferative Neoplasm (MPN) who participated in a prior bomedemstat study such as, but not limited to, IMG-7289-CTP-102/MK-3543-002 (NCT03136185) and IMG-7289-CTP-201/MK-3543-003 (NCT04254978) (referred to hereafter as 'feeder studies').

Conditions

Thrombocythemia, Essential; Primary Myelofibrosis

Outcome Measures

Primary Outcomes (4)

• Percentage of Participants Who Experience an Adverse Event (AE)

  An AE is any undesirable physical, psychological or behavioral effect experienced by a participant during participation in an investigational study, in conjunction with the use of the drug or biologic, whether or not product-related. This includes any clinically significant abnormalities in vital signs and lab values, untoward signs or symptoms experienced by the participant from the time of first dose with bomedemstat under this protocol until completion of the study. The percentage of participants who experienced an AE is presented.

  Up to ~32 months

• Percentage of Participants Who Discontinue Study Intervention Due to an AE

  An AE is any undesirable physical, psychological or behavioral effect experienced by a participant during participation in an investigational study, in conjunction with the use of the drug or biologic, whether or not product-related. This includes any clinically significant abnormalities in vital signs and lab values, untoward signs or symptoms experienced by the participant from the time of first dose with bomedemstat under this protocol until completion of the study. The percentage of participants who discontinued study intervention due to an AE is presented.

  Up to ~32 months

• Mean Spleen Volume Reduction Based on Spleen Volume Measured by MRI in Participants With MF.

  Mean Spleen volume reduction (mL) in participants with MF as measured by central laboratory imaging analysis of MRI (or CT where applicable) approximately every 48 weeks. Per protocol only participants with MF were analyzed for this outcome measure. The change in spleen volume from baseline is presented.

  Baseline and Days 169, 339, 509, 679, 849 and 924

• Percentage of Participants With ET Who Achieve a Reduction of Platelet Counts to <= 400 K/uL (400 x 10^9/L) in the Absence of New Thromboembolic Events

  Blood samples were taken at designated time points to determine platelet count. Percentage of participants with ET who achieve a reduction of platelet counts to \<= 400 K/uL (400 x 10\^9/L) in the absence of new thromboembolic events is presented.

  Baseline and Days 29, 57, 85, 113, 141, 169, 198, 226, 254, 282, 310, 338, 367, 395, 423, 451, 479, 507, 536, 564, 592, 620, and 648

Study Arms (1)

Bomedemstat

EXPERIMENTAL

All participants will receive bomedemstat via oral capsule daily for 169 days with additional treatment continuing in patients deriving clinical benefit.

Drug: Bomedemstat

Interventions

Bomedemstat DRUG

Capsule (oral)

Also known as: IMG-7289, MK-3543

Bomedemstat

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Has completed at least one Treatment Period (TP) in a prior bomedemstat Myeloproliferative Neoplasms (MPN) protocol (such as, but not limited to, IMG-7289-CTP-102/MK-3543-002 (NCT03136185) and IMG-7289-CTP-201/MK-3543-003) (NCT04254978).
• In the estimation of the Investigator, the risk-benefit favors continued dosing with bomedemstat.

You may not qualify if:

• Ongoing participation in another investigational study (except observational studies).
• A history of non-compliance in a prior bomedemstat study (excluding dose suspensions that were medically warranted).
• Current use of a prohibited medication (e.g., romiplostim).
• Medical, psychiatric, cognitive, or other conditions that, in the Investigator's opinion, compromise the patient's safety, ability to give informed consent, or comply with the trial protocol.
• Is pregnant or breastfeeding or plan to become pregnant or breastfeed during the study.
• Women of childbearing potential (WOCBP) and fertile men unwilling to agree to use an approved method of contraception from time of enrollment until 14 days after last bomedemstat dose.

Sponsors & Collaborators

• Imago BioSciences, Inc., a subsidiary of Merck & Co., Inc., (Rahway, New Jersey USA): lead

Study Sites (19)

University of Miami Leonard M. Miller

Miami, Florida, 33136, United States

Location

University of Michigan

Ann Arbor, Michigan, 48109, United States

Location

Cleveland Clinic Foundation

Cleveland, Ohio, 44195, United States

Location

UMPC Hillman Cancer Center

Pittsburgh, Pennsylvania, 15232, United States

Location

Fred Hutchinson Cancer Center

Seattle, Washington, 98109, United States

Location

Royal Prince Alfred Hospital

Camperdown, New South Wales, 2050, Australia

Location

Royal North Shore Hospital

Saint Leonards, New South Wales, 2065, Australia

Location

Gold Coast Hospital and Health Service

Southport, Queensland, 4215, Australia

Location

Royal Adelaide Hospital

Adelaide, South Australia, 5000, Australia

Location

Universittsklinikum Essen

Essen, 45147, Germany

Location

Queen Mary Hospital

Hong Kong, Hong Kong

Location

Ospedale di Circolo-a Fondazione Macchi

Varese, VA, 2100, Italy

Location

Azienda Ospedaliera SS. Antonio

Alessandria, 15121, Italy

Location

Azienda Ospedaliero-Universitaria Careggi - S.O.D. Ematologia (CRIMM)

Florence, 50134, Italy

Location

Azienda Ospedaliero Universitaria di Bologna

Pavia, 27100, Italy

Location

Middlemore Clinical Trials

Papatoetoe, Aukland, 2025, New Zealand

Location

Waitemata District Health Board

Takapuna, Aukland, 0622, New Zealand

Location

University College London Hospitals NHS Foundation Trust

London, NW1 12G, United Kingdom

Location

Guy's and Saint Thomas' NHS Foundation Trus

London, SE1 9RT, United Kingdom

Location

Related Links

• Merck Clinical Trials Information

MeSH Terms

Conditions

Thrombocythemia, Essential; Primary Myelofibrosis

Interventions

bomedemstat

Condition Hierarchy (Ancestors)

Blood Coagulation Disorders; Hematologic Diseases; Hemic and Lymphatic Diseases; Thrombocytosis; Blood Platelet Disorders; Myeloproliferative Disorders; Bone Marrow Diseases; Hemorrhagic Disorders

Results Point of Contact

• Title: Senior Vice President, Global Clinical Development
• Organization: Merck Sharp & Dohme LLC

ClinicalTrialsDisclosure@MSD.com

1-800-672-6372

Study Officials

• Medical Director

  Merck Sharp & Dohme LLC

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 31, 2021
• First Posted: February 4, 2022
• Study Start: December 15, 2021
• Primary Completion: August 22, 2024
• Study Completion: August 22, 2024
• Last Updated: September 22, 2025
• Results First Posted: September 22, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will share

Locations

IT (4); HK (1); NZ (2); GB (2); AU (4); US (5); DE (1)