Phase 3 Trial of Bomedemstat in Essential Thrombocythemia Begins Enrollment

By Sabrina Serani
Fact checked by Jordyn Sava

A pivotal phase 3 trial (NCT06456346) has initiated to evaluate bomedemstat (MK-3543; IMG-7289), an investigational agent for the treatment of patients with essential thrombocythemia (ET) who have previously not received cytoreductive therapy.1

“The standard of care in essential thrombocythemia has remained unchanged for decades, and patients are in need of new options that have the potential to not only improve disease control, but also improve their quality of life,” said Gregory Lubiniecki, MD, vice president, global clinical development, Merck Research Laboratories, in a press release. “We are rapidly advancing our clinical development programs with the goal of helping to address these unmet needs and bring more options to patients living with myeloproliferative neoplasms.”

The Shorespan-007 trial will compare the orally available LSD1 inhibitor bomedemstat with standard-of-care hydroxyurea in patients with treatment-naive ET, the most common myeloproliferative neoplasm. LSD1 is an enzyme that is potentially important for regulating the proliferation of hematopoietic stem cells, as well as the maturation of progenitor cells.

The study’s primary end point is durable clinicohematologic response rate, and secondary end points include duration of hematologic remission, event-free survival, incidence of adverse events, and disease progression rate. Additionally, investigators will be patient-reported outcomes, including fatigue and symptoms.

The FDA previously granted orphan drug and fast track designations to bomedemstat in ET and myelofibrosis, as well as orphan drug designation in acute myeloid leukemia.

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Essential Thrombocythemia Trial Launched Evaluating Bomedemstat

By Alex Biese
Fact checked by Ashley Chan

A second phase 3 clinical trial has been launched for the investigational oral drug bomedemstat as a potential new treatment for patients with essential thrombocythemia.

The Shorespan-007 clinical trial, according to a news release from bomedemstat manufacturer Merck, will investigate the use of the drug among patients with essential thrombocythemia who have not previously received cytoreductive therapy.

The global trial, which is currently recruiting, will compare bomedemstat to the current standard of care chemotherapy, hydroxyurea. The trial, with 300 participants, is expected to be concluded in May 2029, according to its listing on clinicaltrials.gov.

Essential thrombocythemia, part of a group of blood cancers known as myeloproliferative neoplasms (MPNs), is a rare disease in which the bone marrow produces too many platelets, according to The Leukemia & Lymphoma Society. This disease, The Leukemia & Lymphoma Society explained, can cause blood clots to form in a patient’s blood vessels, in turn resulting in serious health issues such as stroke, heart attack or pulmonary embolism.

“The standard of care in essential thrombocythemia has remained unchanged for decades, and patients are in need of new options that have the potential to not only improve disease control but also improve their quality of life,” said Dr. Gregory Lubiniecki, vice president of global clinical development for Merck Research Laboratories, in the company’s news release. “We are rapidly advancing our clinical development programs with the goal of helping to address these unmet needs and bring more options to patients living with myeloproliferative neoplasms.”

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Merck Announces Phase 3 Trial Initiation for Bomedemstat, an Investigational Candidate for the Treatment of Certain Patients With Essential Thrombocythemia

August 27, 2024 6:45 am ET

The initiation of a second Phase 3 clinical trial for bomedemstat demonstrates company’s commitment to advancing research in myeloproliferative neoplasms (MPNs)

Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the initiation of Shorespan-007, a pivotal Phase 3 clinical trial evaluating bomedemstat, an investigational orally available lysine-specific demethylase 1 (LSD1) inhibitor, for the treatment of patients with essential thrombocythemia (ET) who have previously not received cytoreductive therapy. Essential thrombocythemia is a chronic, rare blood disorder and is the most common type of myeloproliferative neoplasm. Global recruitment of the Shorespan-007 trial has begun, with patients now enrolling.

“The standard of care in essential thrombocythemia has remained unchanged for decades, and patients are in need of new options that have the potential to not only improve disease control, but also improve their quality of life,” said Dr. Gregory Lubiniecki, vice president, global clinical development, Merck Research Laboratories. “We are rapidly advancing our clinical development programs with the goal of helping to address these unmet needs and bring more options to patients living with myeloproliferative neoplasms.”

Shorespan-007 is a Phase 3, randomized, double-blind, active comparator-controlled clinical trial ( NCT06456346 ) evaluating bomedemstat compared to the current standard of care chemotherapy, hydroxyurea, for treatment of patients with ET who have previously not received cytoreductive therapy. The trial will enroll approximately 300 patients globally. The primary endpoint of the study is durable clinicohematologic response rate (CHR). Key secondary endpoints include Myelofibrosis Symptom Assessment Form version 4.0 (MFSAF v4.0) individual fatigue symptom item score, Patient-reported Outcomes Measurement Information System (PROMIS) Fatigue SF-7a total fatigue score and MFSAF v4.0 total symptom score. Additional secondary endpoints include duration of hematologic remission, event-free survival and disease progression rate.

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Which Factors Predict Thrombotic Events in Essential Thrombocythemia?

August 13, 2024

The risk for essential thrombocythemia-related events in patients with the disease can be predicted using currently available clinical data, researchers wrote in a letter to the editor appearing in Blood Cancer Journal.

“Although considered the most indolent myeloproliferative neoplasm (MPN), essential thrombocythemia (ET) is linked to burdensome vasomotor symptoms and potentially fatal complications that include thrombosis, hemorrhage, and disease progression to myelofibrosis and aggressive myeloid neoplasms,” Ghaith Abu-Zeinah, MD, a hematologist and oncologist at the Richard T. Silver Myeloproliferative Neoplasms Center at Weill Cornell Medicine, New York, and colleagues wrote. “Prognostic measures to identify those at greatest risk for thrombosis, progression, and death in ET [events] are important for timely risk-adapted intervention with available treatments, and for development of interventional trials to improve event-free survival [EFS]. But predicting risks of events in ET has been difficult because ET is an uncommon and clinically heterogeneous chronic disease.”

Predicting excess mortality and disease progression related to ET presents challenges because such events often occur decades after a patient is diagnosed, the researchers continued.

“Thus, retrospective analysis of large cohorts with sufficiently long follow-up is required to identify prognostic measures to stratify risk in patients with ET,” they wrote.

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Cardiovascular Risk in Philadelphia-Negative Myeloproliferative Neoplasms: Mechanisms and Implications—A Narrative Review

by Samuel Bogdan TodorCristian IchimAdrian Boicean, and Romeo Gabriel Mihaila

Abstract

Myeloproliferative neoplasms (MPNs), encompassing disorders like polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), are characterized by clonal hematopoiesis without the Philadelphia chromosome. The JAK2 V617F mutation is prevalent in PV, ET, and PMF, while mutations in MPL and CALR also play significant roles. These conditions predispose patients to thrombotic events, with PMF exhibiting the lowest survival among MPNs. Chronic inflammation, driven by cytokine release from aberrant leukocytes and platelets, amplifies cardiovascular risk through various mechanisms, including atherosclerosis and vascular remodeling. Additionally, MPN-related complications like pulmonary hypertension and cardiac fibrosis contribute to cardiovascular morbidity and mortality. This review consolidates recent research on MPNs’ cardiovascular implications, emphasizing thrombotic risk, chronic inflammation, and vascular stiffness. Understanding these associations is crucial for developing targeted therapies and improving outcomes in MPN patients.

Are thrombosis, progression, and survival in ET predictable?

June 25, 2024

Ghaith Abu-Zeinah, Katie Erdos, Neville Lee, Ahamed Lebbe, Imane Bouhali, Mohammed Khalid, Richard T. Silver & Joseph M. Scandura

Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm (MPN) that originates from a hematopoietic stem cell harboring a mutated JAK2CALR, or MPL gene, or none of these three mutations (10–15% are “triple negative”). Although considered the most indolent MPN, ET is linked to burdensome vasomotor symptoms, and potentially fatal complications that include thrombosis, hemorrhage, and disease progression to myelofibrosis and aggressive myeloid neoplasms. Prognostic measures to identify those at greatest risk for thrombosis, progression, and death in ET (events) are important for timely risk-adapted intervention with available treatments, and for development of interventional trials to improve event-free survival (EFS). But predicting risks of events in ET has been difficult because ET is an uncommon and clinically heterogenous chronic disease. Predicting progression and excess mortality is even more challenging because these events typically occur decades after ET diagnosis [1]. Thus, retrospective analysis of large cohorts with sufficiently long follow-up is required to identify prognostic measures to stratify risk in patients with ET.

Prognostic models have been developed to assess the risk of thrombosis (IPSET-thrombosis [2]) or overall survival (OS) in ET (IPSET-survival [3], MIPSS-ET [4], and triple A [AAA] [5]). This journal recently published two large retrospective ET cohorts: Gangat et al. at the Mayo Clinic (Mayo) [6] and Loscocco et al. at the Florence Center Research and Innovation of Myeloproliferative Neoplasms (CRIMM) [7]. Both studies confirmed previously identified risk factors for thrombosis, progression and/or death in ET that include older age (Age ≥ 60), male sex, elevated white blood cell count (WBC > 11 × 109/L), elevated absolute neutrophil count (ANC ≥ 8 × 109/L), and low absolute lymphocyte count (ALC < 1.7 × 109/L) at the time of presentation. We evaluated these parameters and current risk models in our cohort of 328 adult patients with ET treated at the Weill Cornell Medicine (WCM) Silver MPN Center over a median follow-up of 6 years [8]. This cohort was rigorously defined according to the 2022 World Health Organization diagnostic criteria and therefore all patients had a diagnostic bone marrow biopsy and had alternative diagnoses scrupulously ruled out. The methods of data collection, retrieval, and analysis used were previously described [9], and cohort characteristics are included in Supplementary Table 1.

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Prospective Analysis Highlights Patterns of Progression to Myelofibrosis Following Essential Thrombocythemia Diagnosis

June 17, 2024

Author(s): Caroline Seymour

Most patients with essential thrombocythemia (95.7%; 1184/1237) included in an analysis of the prospective, observational MOST study (NCT02953704) did not experience disease progression to myelofibrosis, but those who did were found to have had longer duration of disease, higher white blood cell counts, and lower hemoglobin levels at enrollment, according to findings presented at the 2024 EHA Congress.1

Of the 4.3% (n = 53) of patients who progressed to myelofibrosis, a pathologic diagnosis of the disease or grade 2 or greater fibrosis was the most common indicator (49.1%; n = 26) of disease progression, followed by new or worsening splenomegaly coupled with a combination of high white blood cell counts and low hemoglobin levels and platelet counts (22.6%; n = 12). Additional indicators were death from myelofibrosis, myelodysplastic syndrome (MDS), or acute myeloid leukemia (AML; 11.3%; n = 6) and circulating blasts above 1% with new or worsening splenomegaly (5.7%; n = 3); patients also met at least 2 progression criteria (11.3%; n = 6).

“These findings and further analyses of MOST data will add insight into disease progression in patients with essential thrombocythemia and facilitate clinical management of this patient population,” lead study author Ruben A. Mesa, MD, FACP, president and executive director of Atrium Health Levine Cancer Institute and Atrium Health Wake Forest Baptist Comprehensive Cancer Center, and vice dean of cancer programs at Wake Forest University School of Medicine in Charlotte, North Carolina, and coauthors wrote in the poster.

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