Pharmacodynamic Monitoring of Targeted Therapy with Midostaurin By Plasma Inhibitor Activity (PIA) Analysis in FLT3 -ITD Positive AML Patients Enrolled in the AMLSG16-10 Trial: A Study of the AML Study Group (AMLSG)

Background: The multi-targeted tyrosine kinase inhibitor (TKI) Midostaurin has recently been approved by the FDA for the treatment of newly diagnosed acute myeloid leukemia (AML) with FLT3 -ITD mutation in combination with intensive standard chemotherapy (Stone et al. NEJM 2017). Monitoring of the efficacy of such a targeted therapy and correlation of the results with clinical outcome is of major importance. The plasma inhibitor activity (PIA) assay allows to determine the level of dephosphorylation of the target under TKI therapy, which is suggested to correlate, as a marker for activity, with clinical outcome.