KIT and acute myeloid leukemia: Imatinib was proved effective in c-kit positive relapsed or refractory AML although only 4 of 12 patients achieved a hematologic remission.[31] Based on the synergy of imatinib and some chemotherapeutic drugs in in vitro experiments, there was a phase I study published in 2008 that recorded an overall response rate of 43.8% for CLAG-imatinib treated patients.