Response and resistance in 300 patients with BCR-ABL-positive leukemias treated with imatinib in a single center: a 4.5-year follow-up.

Background: The advent of imatinib has considerably changed the treatment of chronic myeloid leukemia (CML). Early studies demonstrated high rates of hematologic and cytogenetic responses in all phases of the disease after limited observation periods.

Methods: The authors evaluated long-term outcome, rates of response, and resistance in 300 patients with BCR-ABL-positive leukemias (CML in chronic phase after failure to respond to interferon-alpha [CP], n = 139; accelerated phase [AP], n = 80; myeloid blast crisis [BC], n = 76; lymphoid BC and Philadelphia chromosome-positive acute lymphoblastic leukemia, n = 5) who entered clinical trials with imatinib in a single center after an observation time of 4.