Complete cytogenetic response in 2 patients treated with dasatinib after imatinib and nilotinib failure. Patient A was in BP and harbored the P-loop mutant E255V/K. This patient was taken off the study in January 2006 to undergo bone marrow transplantation in complete cytogenetic response. Patient B was in accelerated phase and harbored the F359V mutation at dasatinib therapy. KOS-953 indicates the heat shock protein 90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG); Im, imatinib; AMN, nilotinib; BMS, dasatinib; qd, daily; and bid, twice daily.