Thrombocythemia, EssentialPhase 2NCT05223920

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

A Phase 2 study testing Bomedemstat in people with Thrombocythemia, Essential and Primary Myelofibrosis, run by Imago BioSciences, Inc., a subsidiary of Merck & Co., Inc., (Rahway, New Jersey USA) at 19 sites in 7 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial 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… Read more about this study

Who is it for?: Ages 18 years and older
Conditions the study is for: Thrombocythemia, Essential, Primary Myelofibrosis
What is being tested?: Bomedemstat
Type of treatment: Pill or oral medicine
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 81 participants
Where: 19 sitesin 7 countries
Study dates: 15 Dec 2021to 22 Aug 2024
Phase: Phase 2
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 years and older
All sexes
No healthy volunteers
Adult, Older adult

Who may be able to join

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.

Who cannot join

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.

Trial locations and contacts

19 sites in 7 countries.

Country

City, postcode or hospital

19 sites in 7 countries

United States5 sites

University of Michigan
Ann Arbor, Michigan, 48109
Cleveland Clinic Foundation
Cleveland, Ohio, 44195
University of Miami Leonard M. Miller
Miami, Florida, 33136
UMPC Hillman Cancer Center
Pittsburgh, Pennsylvania, 15232
Fred Hutchinson Cancer Center
Seattle, Washington, 98109

Other trials in United States

Australia4 sites

Royal Adelaide Hospital
Adelaide, South Australia, 5000
Royal Prince Alfred Hospital
Camperdown, New South Wales, 2050
Royal North Shore Hospital
Saint Leonards, New South Wales, 2065
Gold Coast Hospital and Health Service
Southport, Queensland, 4215

Other trials in Australia

Italy4 sites

Azienda Ospedaliera SS. Antonio
Alessandria, 15121
Azienda Ospedaliero-Universitaria Careggi - S.O.D. Ematologia (CRIMM)
Florence, 50134
Azienda Ospedaliero Universitaria di Bologna
Pavia, 27100
Ospedale di Circolo-a Fondazione Macchi
Varese, VA, 2100

Other trials in Italy

New Zealand2 sites

Middlemore Clinical Trials
Papatoetoe, Aukland, 2025
Waitemata District Health Board
Takapuna, Aukland, 0622

Other trials in New Zealand

United Kingdom2 sites

University College London Hospitals NHS Foundation Trust
London, NW1 12G
Guy's and Saint Thomas' NHS Foundation Trus
London, SE1 9RT

Other trials in United Kingdom

Germany1 site

Universittsklinikum Essen
Essen, 45147

Other trials in Germany

Hong Kong1 site

Queen Mary Hospital
Hong Kong

Other trials in Hong Kong

About this study

Official title: A Multi-Center, Open Label, Extension Study Evaluating the Safety and Efficacy of Bomedemstat for the Treatment of Patients With Myeloproliferative Neoplasms (MPNs) Enrolled in a Prior Bomedemstat Clinical Study

Conditions: Thrombocythemia, Essential, Primary Myelofibrosis
Being tested: Bomedemstat
Medical subject headings: Thrombocythemia, Essential, Primary Myelofibrosis

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

BomedemstatDrug
Also called IMG-7289, MK-3543
Capsule (oral)

Study groups in NCT05223920
Study group	Role	What they receive
Bomedemstat	Experimental	All participants will receive bomedemstat via oral capsule daily for 169 days with additional treatment continuing in patients deriving clinical benefit. Receives: Drug: Bomedemstat

What is being measured

The primary outcome is the main question the study is designed to answer.

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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

15 Dec 202122 Aug 2024

First posted4 Feb 2022
Study start15 Dec 2021
Primary completion22 Aug 2024
Study completion22 Aug 2024

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Thrombocythemia, EssentialStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 2
Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Enrolment: 81 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05223920
Sponsor's protocol ID: IMG-7289-CTP-202
Other IDs: MK-3543-005, IMG-7289, 2021-002452-37
Status last verified: Sep 2025
First submitted: 31 Aug 2021
Last updated: 22 Sep 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

RecruitingPhase 3
A Phase 3 Study of Pelabresib (DAK539) and Ruxolitinib in Myelofibrosis (MF)
Primary Myelofibrosis (PMF), Post-polycythemia Vera Myelofibrosis (PPV-MF)
RecruitingPhase 3
A Phase 3 Study of INCA033989 Versus Best Available Therapy in Participants With Essential Thrombocythemia
Essential Thrombocythemia
RecruitingPhase 2
Study of Momelotinib in Combination With Luspatercept in Participants With Transfusion Dependent Myelofibrosis
Primary Myelofibrosis, Myelofibrosis; Primary Myelofibrosis; Post-polycythemia Vera Myelofibrosis; Post-essential Thrombocythemia Myelofibrosis
RecruitingPhase 1
Study of INCA036978 in Participants With Myeloproliferative Neoplasms
Myeloproliferative Neoplasms
Recruiting
Functional and Phenotypic Characterization of Monocytes in Myeloproliferative Syndromes
Myeloproliferative Neoplasm, Polycythemia Vera

All Thrombocythemia, Essential trials

Study at a glance

From the registry record, last updated by the sponsor on 22 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Multi-Center, Open Label, Extension Study Evaluating the Safety and Efficacy of Bomedemstat for the Treatment of Patients With Myeloproliferative Neoplasms (MPNs) Enrolled in a Prior Bomedemstat Clinical Study
ClinicalTrials.gov ID: NCT05223920
Acronym / sponsor ID: IMG-7289-CTP-202
Conditions: Thrombocythemia, Essential, Primary Myelofibrosis
Phase: Phase 2
Study type: Interventional
Recruitment status: Completed
Enrolment: 81 participants (actual)
Lead sponsor: Imago BioSciences, Inc., a subsidiary of Merck & Co., Inc., (Rahway, New Jersey USA)Industry (pharma, biotech, devices)
Study start: 15 Dec 2021 (actual)
Primary completion: 22 Aug 2024 (actual)
Study completion: 22 Aug 2024 (actual)
First posted: 4 Feb 2022 (actual)
Results: Posted 22 Sep 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Number of arms: 1

Arm	Type	Receives
Bomedemstat	Experimental	Drug: BomedemstatAll participants will receive bomedemstat via oral capsule daily for 169 days with additional treatment continuing in patients deriving clinical benefit.

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (2 listed)

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.

Key exclusion criteria (6 listed)

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.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
BomedemstatAlso: IMG-7289, MK-3543Capsule (oral)	Drug	Bomedemstat

Primary outcome

Percentage of Participants Who Experience an Adverse Event (AE)
Time frame: Up to ~32 months
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.
Percentage of Participants Who Discontinue Study Intervention Due to an AE
Time frame: Up to ~32 months
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.
Mean Spleen Volume Reduction Based on Spleen Volume Measured by MRI in Participants With MF.
Time frame: Baseline and Days 169, 339, 509, 679, 849 and 924
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.
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
Time frame: 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
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.

Results and safety

Results posted to the registry on 22 Sep 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Essential Thrombocythemia (ET)	52	0
Myelofibrosis (MF)	29	0

Primary outcome: Percentage of Participants Who Experience an Adverse Event (AE)

Time frame: Up to ~32 months. Number. Unit: Percentage of Participants

Measure	Essential Thrombocythemia (ET) n = 52	Myelofibrosis (MF) n = 29
Value	98.1	100.0

Population analysed: All participants who received at least one dose of study intervention

Primary outcome: Percentage of Participants Who Discontinue Study Intervention Due to an AE

Time frame: Up to ~32 months. Number. Unit: Percentage of Participants

Measure	Essential Thrombocythemia (ET) n = 52	Myelofibrosis (MF) n = 29
Value	15.4	10.3

Population analysed: All participants who received at least one dose of study intervention

Primary outcome: Mean Spleen Volume Reduction Based on Spleen Volume Measured by MRI in Participants With MF.

Time frame: Baseline and Days 169, 339, 509, 679, 849 and 924. Mean (Standard Deviation). Unit: mL

Measure	Essential Thrombocythemia (ET) n = 0	Myelofibrosis (MF) n = 29
Day 169	–	-101.570 (92.6876)
Day 339	–	-67.645 (249.0079)
Day 509	–	-5.920 (143.1692)
Day 679	–	-61.000 (396.2520)
Day 849	–	-38.840 (NA)
Day 924	–	80.575 (10.3308)

Population analysed: The modified intent to treat (mITT) population included all participants who were enrolled in the study, received at least 1 dose of study intervention, and who had a nonmissing baseline and at least 1 nonmissing postbaseline efficacy assessment. Participants were analyzed according to treatment received in the study. Per protocol only participants with MF were analyzed for this outcome measure.

Primary outcome: 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

Time frame: 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. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	Essential Thrombocythemia (ET) n = 52	Myelofibrosis (MF) n = 0
Day 29	77.1 (62.7 to 88.0)	–
Day 57	72.9 (58.2 to 84.7)	–
Day 85	72.0 (57.5 to 83.8)	–
Day 113	78.4 (64.7 to 88.7)	–
Day 141	91.8 (80.4 to 97.7)	–
Day 169	89.4 (76.9 to 96.5)	–
Day 198	86.7 (73.2 to 94.9)	–
Day 226	81.8 (67.3 to 91.8)	–

Population analysed: The modified intent to treat (mITT) population included all participants who were enrolled in the study, received at least 1 dose of study intervention, and who had a nonmissing baseline and at least 1 nonmissing postbaseline efficacy assessment. Per protocol only participants with ET were analyzed for this outcome measure. Participants were analyzed according to treatment received in the study.

Adverse events

Time frame: Death and adverse events up to ~32 months. Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Essential Thrombocythemia (ET)	19 of 52 (36.5%)	45 of 52 (86.5%)	2 of 52
Myelofibrosis (MF)	12 of 29 (41.4%)	28 of 29 (96.6%)	0 of 29

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 22 Sep 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Merck Clinical Trials InformationLink provided by the sponsor.
Individual participant dataSharing planned: Yes. https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Related trials for Thrombocythemia, Essential

RecruitingPhase 3
A Phase 3 Study of Pelabresib (DAK539) and Ruxolitinib in Myelofibrosis (MF)
Primary Myelofibrosis (PMF), Post-polycythemia Vera Myelofibrosis (PPV-MF)
RecruitingPhase 3
A Phase 3 Study of INCA033989 Versus Best Available Therapy in Participants With Essential Thrombocythemia
Essential Thrombocythemia
RecruitingPhase 2
Study of Momelotinib in Combination With Luspatercept in Participants With Transfusion Dependent Myelofibrosis
Primary Myelofibrosis, Myelofibrosis; Primary Myelofibrosis; Post-polycythemia Vera Myelofibrosis; Post-essential Thrombocythemia Myelofibrosis
RecruitingPhase 1
Study of INCA036978 in Participants With Myeloproliferative Neoplasms
Myeloproliferative Neoplasms
Recruiting
Functional and Phenotypic Characterization of Monocytes in Myeloproliferative Syndromes
Myeloproliferative Neoplasm, Polycythemia Vera

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Medical Director study director

Merck Sharp & Dohme LLC

19 sites in 7 countries: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 22 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 19 sites in United States, Australia, Italy, New Zealand, United Kingdom and 2 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 22 Sep 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percentage of Participants Who Experience an Adverse Event (AE) (time frame: Up to ~32 months). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05223920.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Sep 2025.