Imago BioSciences, Inc., a subsidiary of Merck & Co., Inc., (Rahway, New Jersey USA)
Who can join
18 and older, any sex, with Thrombocythemia, Essential or Primary Myelofibrosis. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Percentage of Participants Who Experience an Adverse Event (AE)Primary· 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.
Group
Value
95% CI
Essential Thrombocythemia (ET)
98.1
Myelofibrosis (MF)
100.0
Percentage of Participants Who Discontinue Study Intervention Due to an AEPrimary· 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.
Group
Value
95% CI
Essential Thrombocythemia (ET)
15.4
Myelofibrosis (MF)
10.3
Mean Spleen Volume Reduction Based on Spleen Volume Measured by MRI in Participants With MF.Primary· 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.
Day 169
Group
Value
95% CI
Myelofibrosis (MF)
-101.570
± 92.6876
Day 339
Group
Value
95% CI
Myelofibrosis (MF)
-67.645
± 249.0079
Day 509
Group
Value
95% CI
Myelofibrosis (MF)
-5.920
± 143.1692
Day 679
Group
Value
95% CI
Myelofibrosis (MF)
-61.000
± 396.2520
Day 849
Group
Value
95% CI
Myelofibrosis (MF)
-38.840
± NA
Day 924
Group
Value
95% CI
Myelofibrosis (MF)
80.575
± 10.3308
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 EventsPrimary· 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.
Day 29
Group
Value
95% CI
Essential Thrombocythemia (ET)
77.1
62.7 – 88.0
Day 57
Group
Value
95% CI
Essential Thrombocythemia (ET)
72.9
58.2 – 84.7
Day 85
Group
Value
95% CI
Essential Thrombocythemia (ET)
72.0
57.5 – 83.8
Day 113
Group
Value
95% CI
Essential Thrombocythemia (ET)
78.4
64.7 – 88.7
Day 141
Group
Value
95% CI
Essential Thrombocythemia (ET)
91.8
80.4 – 97.7
Day 169
Group
Value
95% CI
Essential Thrombocythemia (ET)
89.4
76.9 – 96.5
Day 198
Group
Value
95% CI
Essential Thrombocythemia (ET)
86.7
73.2 – 94.9
Day 226
Group
Value
95% CI
Essential Thrombocythemia (ET)
81.8
67.3 – 91.8
Adverse events — posted to ClinicalTrials.gov
Time frame: Death and adverse events up to ~32 months.
Reporting threshold: 5%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
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').
Publications & conference data
8 peer-reviewed publications reference this trial (live from Europe PMC):
NCT07049939 — A Study of Bomedemstat (MK-3543) in Participants With Mild or Moderate Hepatic Impairment (MK-3543-023)
· Phase 1
· completed
NCT06456346 — Bomedemstat vs Hydroxyurea for Essential Thrombocythemia (MK-3543-007)
· Phase 3
· recruiting
NCT06351631 — A Study to Evaluate Safety and Efficacy of Bomedemstat (MK-3543-017)
· Phase 3
· recruiting
NCT06079879 — A Study of Bomedemstat (IMG-7289/MK-3543) Compared to Best Available Therapy (BAT) in Participants With Essential Thromb
· Phase 3
· recruiting
NCT05558696 — A Study of Bomedemstat (MK-3543) in Participants With Polycythemia Vera (MK-3543-004)
· Phase 2
· completed
Other recruiting trials for Thrombocythemia, Essential
Currently open trials in the same condition.
NCT07362225 — MPN PROGRESSion Registry: Observational Study Tracking Symptoms, Treatments, and Disease Progression in People With Myel
· recruiting
NCT06351631 — A Study to Evaluate Safety and Efficacy of Bomedemstat (MK-3543-017)
· Phase 3
· recruiting
Other Imago BioSciences, Inc., a subsidiary of Merck & Co., Inc., (Rahway, New Jersey USA) trials
Trials by the same sponsor.
NCT05558696 — A Study of Bomedemstat (MK-3543) in Participants With Polycythemia Vera (MK-3543-004)
· Phase 2
· completed
NCT04254978 — Study of Bomedemstat in Participants With Essential Thrombocythemia (IMG-7289-CTP-201/MK-3543-003)
· Phase 2
· completed
NCT03136185 — Bomedemstat (IMG-7289/MK-3543) in Participants With Myelofibrosis (IMG-7289-CTP-102/MK-3543-002)
· Phase 1, PHASE2
· completed
NCT02842827 — A Study of Bomedemstat (IMG-7289/MK-3543) With and Without ATRA, in Participants With Advanced Myeloid Malignancies (IMG
· Phase 1, PHASE2
· completed
Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Imago BioSciences, Inc., a subsidiary of Merck & Co., Inc., (Rahway, New Jersey USA)
Last refreshed: 22 September 2025
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT05223920.