Merck Initiates Phase 3 Trial for Bomedemstat in Essential Thrombocythemia

Merck, known as MSD outside the United States and Canada, has announced the commencement of Shorespan-007, a crucial Phase 3 clinical trial. This trial aims to evaluate the effectiveness of bomedemstat, an investigational orally available lysine-specific demethylase 1 (LSD1) inhibitor, for patients with essential thrombocythemia (ET) who have not previously undergone cytoreductive therapy. Essential thrombocythemia is a rare but chronic blood disorder and stands as the most common type of myeloproliferative neoplasm. The global recruitment phase for the Shorespan-007 trial is currently underway, and patient enrollment has begun.

Dr. Gregory Lubiniecki, vice president of global clinical development at Merck Research Laboratories, emphasized the necessity for novel treatment options to enhance disease control and improve the quality of life for patients with essential thrombocythemia. He mentioned that the standard of care for this condition has not evolved in decades, highlighting a significant unmet need in the medical community.

The Shorespan-007 trial is a Phase 3, randomized, double-blind study with an active comparator-controlled design. The trial will assess bomedemstat against the current standard chemotherapy, hydroxyurea, in approximately 300 patients globally who have not received prior cytoreductive therapy. The primary objective is to measure the durable clinicohematologic response rate (CHR). Secondary endpoints include various patient-reported outcomes such as fatigue scores and symptom assessments, along with other clinical measures like the duration of hematologic remission, event-free survival, and disease progression rate.

In addition to Shorespan-007, Merck is also conducting another Phase 3 trial, Shorespan-006, which evaluates bomedemstat compared to the best available therapies in patients with essential thrombocythemia who have either not responded adequately to or cannot tolerate hydroxyurea. This trial is also global, randomized, and open-label, involving around 300 patients.

Bomedemstat has received several designations from the U.S. Food and Drug Administration, including Orphan Drug and Fast Track for the treatment of essential thrombocythemia and myelofibrosis, as well as Orphan Drug Designation for acute myeloid leukemia. Additionally, the European Medicines Agency has granted it the Priority Medicines scheme designation for myelofibrosis. Updated findings from the Phase 2b Shorespan-003 trial, which included genomic data, were presented at the American Society of Hematology Annual Meeting in December 2023. This trial is part of a broader evaluation of bomedemstat across multiple Phase 2 studies, examining its efficacy both alone and in combination with other treatments for various myeloproliferative neoplasms such as essential thrombocythemia, myelofibrosis, and polycythemia vera.

Essential thrombocythemia, characterized by the bone marrow producing an excessive number of platelets, can lead to severe complications like stroke, heart attack, or pulmonary embolism. The condition is more prevalent in women and usually affects individuals aged between 50 and 70. In the United States, it is estimated that fewer than 200,000 people are living with this disease, which severely impacts the quality of life due to symptoms like fatigue, insomnia, migraines, headache, and dizziness.

Bomedemstat, also known as MK-3543, is a small molecule, irreversible LSD1 inhibitor under investigation by Merck. LSD1 is crucial for the regulation of hematopoietic stem cells, influencing cell differentiation and maturation. Bomedemstat is being studied across a range of myeloproliferative neoplasms, including essential thrombocythemia, myelofibrosis, and polycythemia vera.

Merck remains dedicated to advancing oncology research, with one of the most extensive clinical development programs covering over 30 types of tumors. The company aims to develop innovative health solutions and improve cancer treatment outcomes, striving to make high-quality cancer care accessible to a broader patient population.