Evaluation of the Toxicity and Outcomes of the Combination of Midostaurin and CLAG-M in Patients With FLT3-Mutated Acute Myeloid Leukemia (AML): A Multicenter Retrospective Analysis

Background: Addition of midostaurin to standard “7+3” (cytarabine and anthracycline) significantly prolongs overall and event-free survival. At University of Washington/Fred Hutchinson Cancer Center (UW/FHCC), the standard regimen for newly diagnosed (ND) and relapsed/refractory (R/R) AML is cladribine, high-dose cytarabine, GCSF, and mitoxantrone (CLAG-M); midostaurin is added if FLT3-mutated. There is limited data on the use of FLT3-inhibitors with high-dose cytarabine regimens in AML. Objective: This study aimed to evaluate the safety and efficacy of the combination of midostaurin with CLAG-M versus midostaurin plus 7+3 in FLT3-mutated AML patients. Methods: This is a retrospective, multicenter review including FLT3-mutated AML patients undergoing (re)induction chemotherapy with either CLAG-M or 7+3 at UW/FHCC, Oregon Health & Science University, and Swedish Cancer Institute. The primary outcome was incidence of adverse events. Secondary outcomes included disease response per ELN2017 criteria and 28-day mortality. Excluded were patients on clinical trials or who started midostaurin 30 days after chemotherapy. Results: Eighty patients treated from September 2016 to December 2023 were included; 36 patients received CLAG-M, and 44 patients 7+3. Baseline characteristics were similar across all institutions. Adverse event rates were similar between the 2 cohorts, except diarrhea and bleeding which were more common in the 7+3 cohort. The rate of complete remission (CR) plus CR with incomplete blood count recovery did not significantly differ between the 2 cohorts: CLAG-M, 86% versus 7+3, 70% ( P = 0.11). Conclusion & relevance: The toxicity profile of CLAG-M combined with midostaurin is comparable with the combination of 7+3 with midostaurin, and induces high remissions rates in adults with FLT3-mutated AML.