New agents for the treatment of acute myeloid leukemia: midostaurin

FLT3, a membrane-bound receptor tyrosine kinase (TK) expressed by immature hematopoietic cells, plays an important role in an early stage of hematopoiesis.1 FLT3 is among the most commonly mutated genes in acute myeloid leukemia (AML). Approximately 30% of AML patients have mutations of FLT3 that result in constitutive phosphorylation and activation of FLT3, and subsequent activation of downstream signal molecules important for cellular proliferation, differentiation, and survival.2 These mutations typically result in either an internal tandem duplication (ITD) of between 3 and 33 or more amino acids in the juxtamembrane region of the FLT3 protein (25% of patients), or a less common (5-10%) point mutation in the activation loop of the thyrosine kinase domaine (TKD).