A new study has determined that midostaurin is the most common therapy administered to treat mast cell leukemia (MCL), a rare subtype of systemic mastocytosis (SM), and that it leads to improved overall survival (OS) compared to other therapies.

The study, published in Blood Advances, noted that the median OS in patients with MCL was 1.6 years and that a diagnosis of MCL with an associated hematologic neoplasm (MCL-AHN) and abnormal karyotype was associated with shorter OS.

“In this study, we describe the clinical characteristics, molecular features, current treatment patterns, and survival outcomes of a well-characterized, multi-institutional cohort of patients with MCL from the European Competence Network on Mastocytosis (ECNM) registry,” the authors wrote. “To our knowledge, this is the largest cohort of patients with this rare advanced myeloid neoplasm.”

The research team collected data on 92 patients with SM from the ECNM registry who were diagnosed with MCL between 1994 and 2019. The median follow-up time was 1.1 years.

The median OS of the cohort was 1.6 years; however, a few patients survived longer. Among the 576 patients with advanced SM from the registry, those with MCL had the poorest OS. A diagnosis of MCL-AHN, an abnormal karyotype, KIT D816V negativity, circulating mast cells, and treatments other than midostaurin were all associated with shorter OS.

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In terms of treatment, half of the patients in the cohort received midostaurin, and they had longer OS times than patients who did not receive it. Eight patients received an allogeneic hematopoietic stem cell transplant; however, it had no effect on their OS.

The authors hope their data will provide clinicians with useful insight into the characteristics of MCL, including its histopathology, molecular genetics, and treatment outcomes.


Kennedy VE, Perkins C, Reiter A, et al. Mast cell leukemia: clinical and molecular features and survival outcomes of patients in the ECNM registry. Blood Adv. Published online September 12, 2022. doi:10.1182/bloodadvances.2022008292