Randomized evaluation of quizartinib and low-dose ara-C vs low-dose ara-C in older acute myeloid leukemia patients

Survival for older patients with acute myeloid leukemia (AML) unsuitable for intensive chemotherapy is unsatisfactory. Standard nonintensive therapies have low response rates and only extend life by a few months. Quizartinib is an oral Fms-like tyrosine kinase 3 (FLT3) inhibitor with reported activity in wild-type patients. As part of the AML LI trial, we undertook a randomized evaluation of low-dose ara-C (LDAC) with or without quizartinib in patients not fit for intensive chemotherapy. Overall, survival was not improved (202 patients), but in the 27 FLT3-ITD patients, the addition of quizartinib to LDAC improved response (P = .05) with complete remission/complete remission with incomplete haematological recovery for quizartinib + LDAC in 5/13 (38%) vs 0/14 (0%) in patients receiving LDAC alone. Overall survival (OS) in these FLT3-ITD(+) patients was also significantly improved at 2 years for quizartinib + LDAC (hazard ratio 0.36; 95% confidence intervals: 0.16, 0.85, P = .04). Median OS was 13.7 months compared with 4.2 months with LDAC alone. This is the first report of an FLT3-targeted therapy added to standard nonintensive chemotherapy that has improved survival in this population. Quizartinib merits consideration for future triplet-based treatment approaches. This trial was registered at www.clinicaltrials.gov as ISRCTN #ISRCTN40571019 and EUDRACT @2011-000749-19.