Quizartinib can prolong OS in rel/ref, FLT3-ITD AML

The overall response rate was 69% in the quizartinib arm and 30% in the chemotherapy arm.

The composite complete response (CR) rate was 48% in the quizartinib arm and 27% in the chemotherapy arm. This includes the CR rate (4% and 1%, respectively), the rate of CR with incomplete platelet recovery (4% and 0%, respectively), and the rate of CR with incomplete hematologic recovery (40% and 26%, respectively). The rate of partial response was 21% and 3%, respectively.

Dr Cortes said rates of treatment-emergent adverse events (TEAEs) were similar between the treatment arms.

Grade 3 or higher hematologic TEAEs occurring in at least 5% of patients (in the quizartinib and chemotherapy groups, respectively) included thrombocytopenia (35% and 34%), anemia (30% and 29%), neutropenia (32% and 25%), febrile neutropenia (31% and 21%), and leukopenia (17% and 16%).

Grade 3 or higher nonhematologic TEAEs occurring in at least 5% of patients (in the quizartinib and chemotherapy groups, respectively) included fatigue (8% and 1%), hypokalemia (12% and 9%), sepsis/septic shock (16% and 18%), dyspnea (5% for both), hypophosphatemia (5% for both), and pneumonia (12% and 9%).

Three percent of patients in the quizartinib arm had grade 3 QTcF prolongation, but there were no grade 4 cases. Two patients discontinued quizartinib due to QTcF prolongation.

“The safety of this drug has remained constant across over 1600 patients that have been treated with quizartinib across a variety of studies,” Dr Cortes said.

He added that QuANTUM-R results open up the possibility that quizartinib could be used in other settings. Researchers are already testing standard chemotherapy with and without quizartinib in a phase 3 trial of patients with newly diagnosed, FLT-ITD AML (QuANTUM-First).