Impact of Timely Switching From Imatinib to a Second-Generation Tyrosine Kinase Inhibitor After 12-Month Complete Cytogenetic Response Failure: A Chart Review Analysis

IntroductionIn this study, cytogenetic response rate after timely switching to a second-generation tyrosine kinase inhibitor (TKI) was evaluated among patients with CML-CP, after failure to achieve CCyR 1 year after imatinib initiation.Patients and MethodsAn online physician-administered medical chart review was used to retrospectively collect information from 108 US-based hematologists and oncologists on CML-CP patients who initiated imatinib as first-line therapy and failed to achieve CCyR at 12 months after imatinib initiation. Patients who switched to a second-generation TKI within 3 months after the CCyR failure were defined as timely switchers, and those who continued taking imatinib for at least 3 months after the CCyR failure were defined as nonswitchers. CCyR achievement was compared between timely switchers and nonswitchers using multivariate Cox proportional hazard models.ResultsPhysicians provided information on 593 patients, with 306 defined as timely switchers and 287 defined as nonswitchers. Among the nonswitchers, 78 switched to a second-generation TKI at a later date. After adjusting for potential confounding factors, timely switchers had statistically significantly greater likelihood of achieving CCyR (hazard ratio, 1.80; P = .002) compared with nonswitchers.ConclusionTimely switching from imatinib to a second-generation TKI after CCyR failure 1 year after imatinib initiation was associated with a greater likelihood of achieving CCyR compared with delaying the switch or not switching to a second-generation TKI.