Researchers developed a new claims-based algorithm that showed the accumulation of severe symptoms over time in a subset of patients with systemic mastocytosis (SM). The study will be presented at the 64th ASH Annual Meeting and Exposition.

The analysis of disease category evolution revealed that 11.3% and 18.8% of patients with lower symptom indolent and smoldering SM (ISM-lower) showed progression to high symptom ISM (ISM-higher) or advanced SM over a 12-month and 24-month interval, respectively. In addition, 2.2% and 3.9% of patients with any type of ISM progressed to advanced SM in 12-month and 24-month intervals, respectively.

The researchers also found that approximately 35% of patients did not have an SM diagnosis 2 years prior to their effective diagnosis. This can be attributed to the recency of the SM ICD-10 codes and to recent efforts to increase timely diagnosis, the researchers explained.

Moreover, the study found that antimediator therapies were the most frequently used therapies (advanced SM, 20%, ISM-higher, 37%, ISM-lower, 20%), followed by cromolyn sodium (advanced SM, 10%, ISM-higher, 19%, ISM-lower, 12%). The low proportion of patients with advanced SM receiving tyrosine kinase inhibitors suggests unmet treatment need.

According to the researchers, “not all ISM [patients] demonstrated truly indolent disease behavior, illustrated by the 30% of ISM [patients] categorized as ISM-high requiring greater use of symptom-directed and disease-specific therapies.”

To create the algorithm, Mukherjee et al used a large, US population representative claims database, which included 10,939 patients with SM. Of those, 80% had claims. The algorithm was based on 2016 World Health Organization diagnostic criteria, including codes for laboratory tests, procedures, and treatments typically used for the management of SM, and aims to identify and classify SM patients, as well as assess patterns of disease progression.


Mukherjee S, Cattie D, Pemmaraju N, Green T, Shaheen D. 3053 Patterns of disease progression in patients with systemic mastocytosis: a US population-level analysis using health claims-based dataset. Poster to be presented at: 64th ASH Annual Meeting and Exposition; December 10-13, 2022; New Orleans, Louisiana.