MIDOKITA Single-arm Phase II Trial to Assess the Efficacy of Midostaurin (PKC412) Added to Standard Primary Therapy in Patients With Newly Diagnosed c-KIT or FLT3-ITD Mutated t(8;21) AML

AML patients displaying t(8;21) have a relatively favourable outcome. Nevertheless, only approximately 50% of patients carrying this cytogenetic aberration are alive at 5 years. This suggests that some patients have more aggressive leukemic phenotypes and indicates the need for treatment optimization with novel therapies. The mutated KIT gene as well as the FLT3-ITD mutation have recently been identified as factors most likely to explain the heterogeneous clinical outcomes within the group of t(8;21) AML. The FLT3 and c-KIT genes encode type III receptor tyrosine kinases (RTK) with important and partly redundant functions in early hematopoietic stem cells. Various activating mutations have been described for both genes. For c-KIT, the incidence ranges from 17 to 48% depending on the source population and type of mutations determined. It has been consistently shown that in AMLs with t(8;21), mutated c-KIT is associated with a dramatically increased risk of relapse and reduced overall survival compared to their unmutated counterparts. The FLT3-ITD mutation has a similar negative effect on prognosis in the patient group of t(8;21) mutated AMLs as c-KIT. PKC412 (midostaurin) is known to inhibit the c-KIT RTK activity as well as the FLT3 kinase, both in patients with ITD and TKD mutations. It should therefore be possible to abrogate the negative impact of pathologically increased c-KIT or FLT3-ITD activity on relapse and overall survival by using midostaurin in this patient population. Aim of the proposed clinical trial is to prove the efficacy of midostaurin in c-KIT or FLT3-ITD mutated t(8;21)- AMLs in an open-label one-arm design.