The development of imatinib as a therapeutic agent for chronic myeloid leukemia

Imatinib has revolutionized drug therapy of chronic myeloid leukemia (CML). Preclinical studies were promising but the results of clinical trials by far exceeded expectations. Responses in chronic phase are unprecedented, with rates of complete cytogenetic response (CCR) of more than 40% in patients after failure of interferon-alpha (IFN) and more than 80% in newly diagnosed patients, a level of efficacy that led to regulatory approval in record time. While most of these responses are stable, resistance to treatment after an initial response is common in more advanced phases of the disease. Mutations in the kinase domain (KD) of BCR-ABL that impair imatinib binding have been identified as the leading cause of…