Spotlight on dasatinib in chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia.

Dasatinib (Sprycel®) is an orally administered small molecule inhibitor of multiple tyrosine kinases, including BCR-ABL and SRC family kinases, which is indicated for the treatment of adults with newly diagnosed chronic-phase chronic myeloid leukemia (CML), CML (chronic-, accelerated- or blast-phase) with resistance or intolerance to prior therapy, including imatinib, or Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) with resistance or intolerance to prior therapy. Dasatinib is ≈325-fold more active than imatinib in inhibiting wild-type BCR-ABL kinase in vitro and is active against a wide variety of imatinib-resistant BCR-ABL mutants, except for T315I. This article reviews the efficacy and tolerability of dasatinib in the treatment of patients with newly diagnosed chronic-phase CML or imatinib-resistant or -intolerant CML or Ph+ ALL, as well as summarizing its pharmacologic properties. In clinical trials, oral dasatinib was effective in achieving major or complete cytogenetic responses in both newly diagnosed and imatinib-resistant or -intolerant chronic-phase CML. Dasatinib was likewise effective in achieving major or overall hematologic responses in imatinib-resistant or -intolerant, accelerated- or blast-phase CML, or Ph+ ALL. Responses were rapidly achieved within 1-3 months and were durable over 1-5 years of follow-up. The majority of adverse events with dasatinib were of mild or moderate severity. Fluid retention (including pleural effusion) was the most common adverse event. Hematologic abnormalities were common and cytopenias were the most common grade 3/4 adverse events. Dasatinib 100 mg administered once daily was as effective as dasatinib 70 mg administered twice daily, and was better tolerated, being associated with lower incidences of pleural effusion and grade 3/4 thrombocytopenia, in particular. Dasatinib was more effective than high-dose imatinib in the treatment of patients with imatinib-resistant chronic-phase CML and was more effective than standard dosages of imatinib, as well as being associated with less frequent fluid retention, in patients with newly diagnosed chronic-phase CML. Dasatinib was generally equally effective in patients with or without BCR-ABL mutations at baseline. Therefore, oral dasatinib is a highly effective, once-daily therapy for the first-line treatment of newly diagnosed patients with chronic-phase CML, as well as for the treatment of patients with imatinib-resistant or -intolerant chronic- and advanced-phase CML or Ph+ ALL.