In April 2017
midostaurin was approved by the US Food and Drug Administration for the treatment of patients with
aggressive systemic mastocytosis (ASM). So far, very limited real world data on its efficacy is available. Thirteen patients aged from 48 to 79 years, who received
midostaurin in the early access program, were included in the study.
Midostaurin was used both in first (n = 5) and subsequent lines of treatment (n = 8). The median duration of exposure was 9 months. Most patients (77%, n = 10) had a clinical improvement already as soon as the second month of
therapy. Objective response was noted in 4 (50%) of eight evaluated patients. Among responders, we observed a decrease in serum
tryptase level (median 74.14%) and bone marrow infiltration by mast cells (median 50%) in the sixth month of treatment. In one case, in the 10th month of treatment, allogenic
stem cell transplantation was performed, achieving complete remission. Five patients died, three due to progression of disease, one in the course of secondary
acute myeloid leukemia and one due to reasons not related to
mastocytosis. Treatment is ongoing in seven patients. We found that
midostaurin therapy is beneficial to patients with ASM.