Activity and safety of dasatinib as second-line treatment or in newly diagnosed chronic phase chronic myeloid leukemia patients

Dasatinib is an oral dual tyrosine kinase inhibitor active against ABL1 and SRC family kinases. The US FDA approved it for the treatment of chronic myeloid leukemia (CML) patients in chronic, accelerated, or blastic phase with resistance or intolerance to imatinib therapy. Dasatinib is also indicated for the treatment of adults with Philadelphia chromosome-positive acute lymphoblastic leukemia who have become resistant to or intolerant of other treatments. The agent is now also approved for newly diagnosed chronic phase (CP) patients. This article reviews the pharmacokinetic and pharmacodynamic properties of dasatinib as well as clinical data limited to CP-CML patients. Four-year follow-up of a phase III dose-optimization trial confirmed that better progression-free survival (66%) and overall survival (82%) were obtained with a dose of 100 mg once daily (od) than with the standard 70 mg twice daily dosing (65% and 75%, respectively). The 100 mg od dosing schedule was also associated with the highest benefit-risk ratio for CP patients with resistant, intolerant, or suboptimal response. Recent results of a phase III trial in newly diagnosed patients demonstrated that dasatinib 100 mg od has superiority in terms of confirmed cytogenetic and molecular responses, with faster responses and high activity in high Sokal risk patients compared with standard-dose imatinib.

New developments in the treatment of chronic myeloid leukemia and Philadelphia-positive acute lymphoblastic leukemia

Although imatinib revolutionized the management of chronic myeloid leukemia (CML), recent data indicate a transformation in the treatment approach likely in the near future. The superiority of second-generation tyrosine kinase inhibitors (TKIs) over imatinib in newly diagnosed disease has been recognized. Several investigational agents specific for those patients with the T315I mutation remain under evaluation. In Philadelphia-positive (Ph-positive) acute lymphoblastic leukemia (ALL), the addition of imatinib improved response rates. However, short remission durations with single agent therapy limit the benefit on survival. Early molecular remissions achieved with dasatinib will enable more patients to proceed to stem cell transplant (SCT), with increased likelihood of positive outcomes post-SCT.