NCT06456346 · Merck Sharp & Dohme LLC
Bomedemstat vs Hydroxyurea for Essential Thrombocythemia (MK-3543-007)
What this study is about
The purpose of this study is to evaluate the effectiveness and safety of bomedemstat compared with hydroxyurea in cytoreductive therapy naïve essential thrombocythemia (ET) participants for whom cytoreductive therapy is indicated. Its primary objective is to compare bomedemstat to hydroxyurea with respect to durable clinicohematologic response (DCHR).
View original scientific description
The purpose of this study is to evaluate the efficacy and safety of bomedemstat compared with hydroxyurea in cytoreductive therapy naïve essential thrombocythemia (ET) participants for whom cytoreductive therapy is indicated. Its primary objective is to compare bomedemstat to hydroxyurea with respect to durable clinicohematologic response (DCHR). The primary hypothesis is that bomedemstat is superior to hydroxyurea with respect to DCHR.
Interventions
DRUG
Bomedemstat
Oral capsule
DRUG
Hydroxyurea
Oral capsule
DRUG
Bomedemstat placebo
Oral capsule placebo
DRUG
Hydroxyurea placebo
Oral capsule placebo
Primary outcome measures
Durable Clinicohematologic Response (DCHR) Rate
Time frame: Up to Week 52
DCHR rate is the percentage of participants with DCHR, defined as a confirmed reduction of platelet count to ≤400 × 10\^9/L, absence of white blood cell (WBC) count elevation to \>10 × 10\^9/L locally assessed to be due to ET, starting by Week 24 and maintained for at least 24 weeks, and the absence of any thrombotic or major hemorrhagic events or disease progression to myelofibrosis (MF), myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) by Week 52.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Diagnosis of Essential Thrombocythemia (ET) based on World Health Organization Criteria for myeloproliferative neoplasms, and an indication for cytoreductive therapy regardless of age or risk status
- Has a centrally assessed bone marrow fibrosis score of Grade 0 or Grade 1, as per a modified version of the European Consensus Criteria for Grading Myelofibrosis
- Has received no prior cytoreductive treatment for their ET
- Human Immunodeficiency Virus (HIV)-infected participants have well controlled HIV on antiretroviral therapy
- Participants who are Hepatitis B surface antigen (HBsAg) positive are eligible if they have received Hepatitis B Virus (HBV) antiviral therapy for at least 4 weeks and have undetectable HBV viral load
- Participants with history of Hepatitis C Virus (HCV) infection are eligible if HCV viral load is undetectable
Exclusion criteria
- History of any illness/impairment of gastrointestinal function that might interfere with drug absorption
Where
- Glendale, Arizona
- Glendale, California
- Palo Alto, California
- Golden, Colorado
- New Haven, Connecticut
- Fort Wayne, Indiana
- Ann Arbor, Michigan
- Las Vegas, Nevada
- Charlotte, North Carolina
- Durham, North Carolina
- Winston-Salem, North Carolina
- Columbus, Ohio
And 10 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 13, 2026 · Source of record for eligibility and locations