Merck Launches Shorespan-007 Clinical Trial of Bomedemstat for Essential Thrombocythemia

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Merck has initiated the pivotal Phase III Shorespan-007 clinical trial to evaluate bomedemstat, an investigational oral LSD1 inhibitor, for the treatment of essential thrombocythemia (ET) in patients who have not received prior cytoreductive therapy. Currently, the trial is in the recruitment process globally and is expected to compare bomedemstat to the current standard of care, hydroxyurea in the treatment of ET.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, VP, 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 randomized, double-blind, active comparator-controlled Shorespan-007 trial will enroll 300 patients globally with a primary endpoint of durable clinicohematologic response rate (CHR). 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, MFSAF v4.0 total symptom score, duration of hematologic remission, event-free survival (EFS), and disease progression rate (DPR).

Merck is also in the process of evaluating bomedemstat in the Phase III, global, randomized, open-label, active comparator-controlled Shorespan-006 trial, which will compare the treatment to the best available therapy in approximately 300 patients with ET who have an inadequate response to or are intolerant of hydroxyurea.1 The primary endpoint of this study is durable clinicohematologic response, with secondary endpoints including duration of clinicohematologic response, duration of hematologic remission, DPR, and EFS. Shorespan-006 was announced back in January, along with three other investigational candidates.²

“These Phase 3 trial initiations for four of our investigational candidates represent a critical step forward in our efforts to advance potential treatment options for people with solid tumors and hematologic neoplasms and malignancies,” said Marjorie Green, MD, SVP, head of oncology, global clinical development, Merck Research Laboratories, in a press release. “We have a proud legacy of turning breakthrough science into medicines that save and improve lives around the world, and we are dedicated to continuing research to expand our broad portfolio of oncology therapeutics to continue to address unmet needs in cancer care.”

According to the Leukemia & Lymphoma Society, the incidence of ET globally is approximately 2.2 per 100,000 population annually. While it is more common in adults, it can occasionally occur in older children as well. Additionally, the prevalence rate is an estimated 24 cases per 100,000 population.³

In the United States, prevalence is estimated at 1 in 4200 . While it can occur at any age, the median age at diagnosis is between 60 and 65 years. It is more common in women, with a 2:1 ratio.

Survival is considered comparable to the healthy population matched by age and sex during the first decade after diagnosis, possibly differentiating in later years due to disease progression. Generally, life expectancy of ET patients can be similar to that of general population if properly managed.⁴

Bomedemstat has received Orphan Drug and Fast Track designations from the FDA for ET and myelofibrosis (MF), and Priority Medicines scheme designation by the European Medicines Agency for the treatment of MF.¹

References

1. Merck Announces Phase 3 Trial Initiation for Bomedemstat, an Investigational Candidate for the Treatment of Certain Patients With Essential Thrombocythemia. Merck. August 27, 2024. Accessed August 27, 2024. https://www.merck.com/news/merck-announces-phase-3-trial-initiation-for-bomedemstat-an-investigational-candidate-for-the-treatment-of-certain-patients-with-essential-thrombocythemia/

2. Merck Announces Phase 3 Trial Initiations for Four Investigational Candidates From its Promising Hematology and Oncology Pipeline. Merck. January 5, 2024. Accessed August 27, 2024. https://www.merck.com/news/merck-announces-phase-3-trial-initiations-for-four-investigational-candidates-from-its-promising-hematology-and-oncology-pipeline/

3. Essential Thrombocythemia Facts. Leukemia & Lymphoma Society. Accessed August 27, 2024. https://www.lls.org/sites/default/files/file_assets/essentialprimarythrombocythemia.pdf

4. Essential thrombocythemia. Orphanet. Accessed August 27, 2024. https://www.orpha.net/en/disease/detail/3318