For a study, the researchers sought to look back on their experience with midostaurin therapy in 33 patients with advanced systemic mastocytosis (adv-SM): aggressive SM (n=17), SM accompanied by another hematologic malignancy (SM-AHN; n=14), and mast cell leukaemia (MCL; n=2). KITD816V mutations were found in 84% of patients, while C findings were found in 91%. About 11 patients (33%), including cladribine (n=4) and imatinib (n=3), had previously been treated with other cytoreductive medicines. From diagnosis to midostaurin therapy commencement, the median duration was 2.2 months (range 0.3–41). The overall response rate was 42% (53% ASM, 29% SM-AHN, 50% MCL; p=.22), all of which were classed as significant. In 40% of the cases studied, bone marrow mast cells were reduced by more than or equal to 50%, and serum tryptase was normalised in 29% of the cases. About 7 (21%) deaths, 1 (3% leukemic progression), and 18 (55%) treatment discontinuations were documented after a median follow-up of 14.6 months from the start of midostaurin therapy; median duration of midostaurin treatment was 7.9 months (range 0.5–123), and response duration 21.5 months (range 2.9–123). The most common side event was gastrointestinal (51%), followed by grade 3/4 neutropenia or thrombocytopenia (12%). The KIT mutation (p=.67) or prior cytoreductive therapy (p=.44) did not affect treatment response. Midostaurin responders had a slightly longer median survival (median 26.5 vs 16 months; p=.15). The study’s outcomes were broadly compatible with previously reported clinical trial outcomes.
Source:onlinelibrary.wiley.com/doi/10.1002/ajh.26498
