A Study to Evaluate Safety and Efficacy of Bomedemstat (MK-3543-017)

A Multicenter, Open-Label, Extension Study Evaluating the Safety and Efficacy of Bomedemstat for the Treatment of Participants Enrolled in a Prior Bomedemstat Clinical Study

The primary purpose of the study is to transition participants into an extension study to collect long-term safety and efficacy data. The study will include participants who are safely tolerating bomedemstat, receiving clinical benefit from its use in estimation of the investigator, and have shown the following criteria:

• Participants from the IMG-7289-202/MK-3543-005 (NCT05223920) study must have received at least 6 months of treatment with bomedemstat;
• Essential thrombocythemia (ET) and polycythemia vera (PV) participants from studies other than IMG-7289-202/MK-3543-005 must have achieved confirmed hematologic remission.

No hypothesis testing will be conducted in this study.

Study Overview

• Status: Not yet recruiting
• Conditions: Primary Myelofibrosis; Polycythemia Vera; Thrombocythemia, Essential; Myelofibrosis; Post-polycythemia Vera Myelofibrosis; Post-essential Thrombocythemia Myelofibrosis
• Intervention / Treatment: Drug: Bomedemstat

• Study Type: Interventional
• Enrollment (Estimated): 400
• Phase: Phase 3

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Is from a bomedemstat study sponsored by Imago Biosciences, Inc. (a subsidiary of Merck & Co., Inc.) or MSD, and established by the Sponsor as MK-3543-017 ready.
• Has received at least 6 months of treatment with bomedemstat in the IMG-7289-202/MK-3543-005 study, while safely tolerating bomedemstat, and receiving clinical benefit from its use in the estimation of the investigator
• ET and PV participants from established feeder studies other than IMG-7289- 202/MK-3543-005 must have achieved confirmed hematologic remission, must be safely tolerating bomedemstat, and must be receiving clinical benefit from its use in the estimation of the investigator
• Be able to initiate study intervention on Day 1 of the extension study (ie, not currently on a dose hold)
• Participant must be able to swallow oral medication and follow instructions for at-home dosing of bomedemstat

Exclusion Criteria:

• Has received prohibited concomitant medications
• Ongoing or planned participation in another investigational study
• Has noncompliance in prior bomedemstat study receiving <90% of assigned doses excluding suspensions or holds as assigned by the investigator

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 oral capsules of bomedemstat once daily for up to 10 years, with the starting dose as the same dose that the participant was on at the time of transition from the feeder study.	Drug: Bomedemstat; 10, 15, 20, and 50 mg oral capsules; Other Names: IMG-7289; MK-3543

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of participants with one or more adverse events (AEs)	An AE is any undesirable physical, psychological or behavioral effect experienced by a patient during participation in an investigational study, in conjunction with the use of the drug or biologic, whether or not product-related. This includes any untoward signs or symptoms experienced by the patient from the time of first dose with bomedemstat under this protocol until completion of the study. The percentage of participants with AEs will be presented.	Up to ~10 years
Percentage of participants who discontinued study treatment due to an AE	An AE is any undesirable physical, psychological or behavioral effect experienced by a patient during participation in an investigational study, in conjunction with the use of the drug or biologic, whether or not product-related. This includes any untoward signs or symptoms experienced by the patient from the time of first dose with bomedemstat under this protocol until completion of the study. The percentage of participants who discontinued study treatment due to an AE will be presented.	Up to ~10 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
For participants with ET or PV: Duration of clinicohematologic response	For participants who showed durable clinicohematologic response (DCHR) in their feeder studies, duration of clinicohematologic response is defined as the time from the first documented evidence of confirmed reduction of platelet and white blood cell (WBC) count until confirmed increase of platelet and WBC counts to above acceptable threshold, thrombotic or major hemorrhagic events or disease progression to myelofibrosis (MF), myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). The duration of clinicohematologic response will be reported.	Up to ~10 years
For participants with ET or PV: Duration of hematologic remission	For participants who showed confirmed hematologic remission in their feeder studies, duration of hematologic remission is defined as the time from the first documented evidence of confirmed reduction of platelet and WBC count until confirmed increase of platelet and WBC counts to above acceptable threshold. The duration of hematologic remission will be reported.	Up to ~10 years
For participants with ET or PV: Percentage of participants with transformation to MF or MDS/AML	Disease Progression is defined as the transformation to post-ET myelofibrosis (ET participants only), post-PV myelofibrosis (PV participants only), spleen volume increase ≥25% (MF participants only), myelodysplastic syndrome, or acute myeloid leukemia as assessed by the investigator. The percentage of participants with transformation to MF or MDS/AML will be reported.	Up to ~10 years
For participants with MF: Percentage of participants with worsening of splenomegaly or transformation to MDS/AML	Spleen volume will be assessed by magnetic resonance imaging (MRI) (or computed tomography [CT] where applicable) at pre-specified timepoints. The percentage of participants with worsening of splenomegaly or transformation to MDS/AML will be reported.	Up to ~10 years
For participants with MF, ET, or PV: Percentage 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 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. The percentage of participants with thrombotic events will be presented.	Up to ~10 years
For participants with MF, ET, or PV: Percentage of participants with major hemorrhagic events	Hemorrhagic events are 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. The percentage of participants with major hemorrhagic events will be presented.	Up to ~10 years
For participants with MF, ET, or PV: Event-Free Survival (EFS)	EFS is defined as the time from feeder study randomization (if randomized feeder study) or first dose (if nonrandomized feeder study) to the first documented occurrence of thrombotic or major hemorrhagic event or disease progression as assessed by the investigator, or death due to any cause, whichever occurs first. EFS will be reported.	Up to ~10 years

Collaborators and Investigators

• Sponsor: Merck Sharp & Dohme LLC
• Investigators: Study Director: Medical Director, Merck Sharp and Dohme LLC

Publications and helpful links

Helpful Links

• Merck Clinical Trials Information
• Plain Language Summary

Study record dates

Study Major Dates

• Study Start (Estimated): May 21, 2024
• Primary Completion (Estimated): December 4, 2034
• Study Completion (Estimated): December 4, 2034

Study Registration Dates

• First Submitted: April 2, 2024
• First Submitted That Met QC Criteria: April 2, 2024
• First Posted (Actual): April 8, 2024

Study Record Updates

• Last Update Posted (Actual): May 6, 2024
• Last Update Submitted That Met QC Criteria: May 2, 2024
• Last Verified: May 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms; Neoplasms by Site; Bone Marrow Diseases; Hematologic Diseases; Hemorrhagic Disorders; Myeloproliferative Disorders; Blood Coagulation Disorders; Blood Platelet Disorders; Bone Marrow Neoplasms; Hematologic Neoplasms; Primary Myelofibrosis; Thrombocytosis; Thrombocythemia, Essential; Polycythemia Vera; Polycythemia
• Other Study ID Numbers: 3543-017; 2023-506996-89 (Other Identifier: EU CT); U1111-1294-8621 (Other Identifier: UTN); MK-3543-017 (Other Identifier: Merck ID)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: http://engagezone.msd.com/doc/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