Optimizing therapy for patients with chronic myelogenous leukemia in chronic phase.

Identification of BCR-ABL as the defining leukemogenic event in chronic myelogenous leukemia (CML) revolutionized the treatment of the disease. Imatinib, a potent BCR-ABL inhibitor, is the standard of care for the first-line treatment of patients with chronic-phase CML because of its high long-term response rates and favorable tolerability profile compared with previous standard therapies. However, resistance to imatinib develops in 2% to 4% of patients annually. For patients with acquired cytogenetic resistance to standard-dose imatinib (400 mg daily), imatinib dose escalation (600-800 mg daily) is an excellent first option for managing patients and achieving cytogenetic responses. However, for patients with primary resistance to imatinib, hematologic disease recurrence, or emergent BCR-ABL kinase domain mutations, imatinib dose escalation may not be sufficient to control the disease. For these patients, the potent second-generation tyrosine kinase inhibitors dasatinib and nilotinib are available. Both agents provide effective therapeutic options for patients with imatinib resistance or intolerance. For the current overview, the authors reviewed the data supporting the use of both dasatinib and nilotinib in imatinib-resistant or imatinib-intolerant patients, and they have highlighted the future of CML therapy. Overall, the article is intended to offer physicians a comprehensive review of the current literature and to provide data supporting various treatment options for patients with CML throughout the course of imatinib therapy and beyond.