Kaplan-Meier estimate of remission duration. Kaplan-Meier estimate of remission duration was calculated separately for patients found to have an unmutated BCR-ABL (WT; solid line) or any kinase domain mutation (hatched line) prior to imatinib exposure. Remission duration was calculated from time of first documented complete remission (CR or CRi) to hematologic relapse. Patients who died in CR were censored at the time of death (death in CR was considered a non-event for calculation of remission duration by Kaplan-Meier analysis). Median remission duration was 436 days in the group of patients with initially unmutated BCR-ABL and 319 days in patients harboring an initial KD mutation (P = .24).