Astellas Pharma Inc. (Tokyo: 4503, Astellas) and Ambit Biosciences Corporation today announced the initiation of a Phase 2b open-label clinical trial of quizartinib as monotherapy in patients with relapsed and refractory acute myeloid leukemia (AML) with FLT3-ITD mutations.
The trial will enroll approximately 64 adult patients (the estimated enroll of the protocol) in the United States and Europe to evaluate two oral doses of quizartinib in 28-day cycles. The co-primary endpoints of the study are (i) the composite complete response (CRc) rate, defined as the sum of complete remission (CR), complete remission with incomplete platelet recovery (CRp) and complete remission with incomplete hematologic recovery (CRi), and (ii) the Grade 2 or higher QT interval prolongation at each dose level. The trial was designed based on the results from an interim analysis of the ACE trial (another monotherapy Phase 2 trial conducted by Ambit), which were presented last year at the American Society of Hematology Meeting. The 333 patients included in the ACE trial were either at least 60 years old and relapsed or refractory to first-line chemotherapy (Cohort 1), or at least 18 years old and relapsed or refractory to second-line chemotherapy or hematopoietic stem cell transplantation (HSCT) (Cohort 2). Final results of the ACE trial will be presented later this year at a medical conference.