Dasatinib, even at low doses, is an effective second-line therapy for chronic myeloid leukemia patients resistant or intolerant to imatinib. Results from a real life-based Italian multicenter retrospective study on 114 patients

Abstract

Dasatinib is effective for the treatment of chronic myeloid leukemia (CML) patients resistant or intolerant to imatinib. However, to date, most of the available data come from studies in which censorization was applied. One-hundred and fourteen CML patients resistant or intolerant to imatinib received dasatinib as second-line therapy outside from clinical trials. Response (hematologic, cytogenetic, and molecular), toxicities, event-free survival (EFS) and overall survival (OS) were evaluated. At 12 months, cumulative incidences of complete hematologic response, complete cytogenetic response (CCyR), and major molecular response were 94%, 51%, and 32%. Cumulative EFS and OS were 91 and 93%. Neither the dose, nor the duration, nor the response to prior imatinib affected the probability of achieving CCyR at 1 year with dasatinib (P = 0.7, 0.9, and 0.8). Moreover, we observed statistically significant better EFS and OS for patients receiving low-dose continuous therapy with dasatinib after dose reduction due to toxicity (50/70 mg/day) with respect to patients who received higher doses (100/140 mg/day) but discontinued temporarily the treatment (P = 0.04, P = 0.04). These findings show, for the first time, a possible effect for dasatinib at low doses in inducing or maintaining response (hematologic, cytogenetic, and molecular) in CML patients resistant or intolerant to Imatinib.