Randomised 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 leukaemia (AML) unsuitable for intensive chemotherapy is unsatisfactory. Standard non intensive 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 randomised 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=0.05) with CR/CRi for quizartinib + LDAC in 5/13 (38%) v 0/14 (0%) in patients receiving LDAC alone. Overall survival (OS) in these FLT3-ITD positive patients was also significantly improved at 2 years for quizartinib + LDAC; hazard ratio 0.36 (95% confidence intervals 0.16, 0.85), (p=0.04). Median OS was 13.7 months compared to 4.2 months with LDAC alone. This is the first report of a FLT3 targeted therapy added to standard non-intensive chemotherapy that has improved survival in this population. Quizartinib merits consideration for future triplet based treatment approaches. (Clinical trial numbers: ISRCTN No: ISRCTN40571019 EUDRACT Number: 2011-000749-19).