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RecruitingLast updated: 22 October 2025

MK-3543-006: This study is evaluating how safe and effective an oral treatment called Bomedemstat is compared to best available therapy in people with essential thrombocythemia who have an inadequate response or are intolerant of hydroxyureaA Phase 3, Randomized, Open-label, Active-Comparator-Controlled Clinical Study to Evaluate the Safety and Efficacy of Bomedemstat (MK-3543/IMG-7289) Versus Best Available Therapy (BAT) in Participants With Essential Thrombocythemia Who Have an Inadequate Response to or Are Intolerant of Hydroxyurea

Trial purpose

Medical clipboardCancer treatment

Tumor type

Blood Cancers Haematological

Age

People18+

Trial acronym

MK-3543-006

Clinical summary

Summary

Eligible participants will be randomly allocated to one of two treatment arms. 

In the Experimental Arm, participants will receive Bomedemstat, which is an orally active LSD1 inhibitor. Participants will begin treatment at a dose of 50mg of Bomedemstat daily. Dosage will be adjusted either up or down within specified time parameters for each participant to the dose that provides sufficient exposure to safely inhibit thrombopoiesis to decrease platelet counts to the target range. All participants will be treated daily for up to 52 weeks, and are eligible for an extended treatment phase up to 152 weeks.

In the Active Comparator Arm, participants will receive Best Available Therapy (BAT) of either anagrelide, busulfan, interferon alpha/pegylated interferon alfa, or ruxolitinib. All participants will be treated per respective approved product labels for up to 52 weeks. Participants receiving BAT for 52 weeks who stop responding to BAT are eligible to switch to bomedemstat and receive this for up to 152 weeks at the Investigator's discretion.

Conditions

This trial is treating people with essential thrombocythemia

Eligibility

Inclusion

  • Has a diagnosis of ET per WHO 2016 diagnostic criteria for myeloproliferative neoplasms
  • Has a bone marrow fibrosis score of Grade 0 or Grade 1, as per a modified version of the European Consensus Criteria for Grading Myelofibrosis
  • Has a history of inadequate response to or intolerance of hydroxyurea based on modified European LeukemiaNet (ELN) criteria for hydroxyurea resistance or intolerance: hydroxyurea resistance (or inadequate response) or hydroxyurea Intolerance
  • Has an inadequate or loss of response to their most recent prior ET therapy, requiring a change of cytoreductive therapy
  • Has a platelet count > 450 × 10^9/L (450k /μL) assessed up to 72 hours before first dose of study intervention
  • Has an absolute neutrophil count (ANC) ≥0.75 × 10^9/L assessed up to 72 hours before first dose of study intervention
  • Participants may have received up to 3 prior lines of therapy including hydroxyurea

Exclusion

  • Known immediate or delayed hypersensitivity reaction or idiosyncrasy to drugs chemically related to bomedemstat or lysine demethylase or monoamine oxidase inhibitor (LSDi or MAOi) or the chosen best available therapy (including anagrelide, interferon alfa/pegylated interferon, ruxolitinib, or busulfan) that contraindicates participation
  • History of any illness/impairment of GI function that might interfere with drug absorption (eg, chronic diarrhea or history of gastric bypass surgical procedure), confound the study results or pose an additional risk to the individual by participation in the study
  • Evidence at the time of Screening of increased risk of bleeding
  • History of a malignancy, unless potentially curative treatment has been completed with no evidence of malignancy for 2 years. Note: The time requirement does not apply to participants who underwent successful definitive resection of basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or carcinoma in situ, excluding carcinoma in situ of the bladder
  • Human immunodeficiency virus (HIV)-infected participants with a history of Kaposi's sarcoma and/or Multicentric Castleman's Disease

Inclusion

  • You have had treatment but your cancer has gotten worse or has not responded to the treatment you have been given.
  • You are currently receiving treatment for your cancer.
  • You are able to swallow medication by mouth.

Exclusion

  • You have been diagnosed with a prior or secondary type of cancer.
  • You have certain types of non-cancer medical conditions.
Message

Clinical trials have complex eligibility criteria, and other criteria may apply for this trial. Ask your doctor about whether this trial could be right for you.

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More information

Trial Identifiers

Information on this page is partially produced from ClinicalTrials.gov *. View further details about this trial on the registry via the links below:

  • NCT06079879 *
  • 3543-006; 2023-504865-21; IMG-7289-CTP-301; MK-3543-006; JRCT2031230658

Trial sponsor

Merck Sharp & Dohme LLC

Scientific Title

A Phase 3, Randomized, Open-label, Active-Comparator-Controlled Clinical Study to Evaluate the Safety and Efficacy of Bomedemstat (MK-3543/IMG-7289) Versus Best Available Therapy (BAT) in Participants With Essential Thrombocythemia Who Have an Inadequate Response to or Are Intolerant of Hydroxyurea

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