Kaplan-Meier analysis of rate of survival and disease progression in patients in chronic phase following imatinib therapy according to deletion status. (A) Survival from initiation of imatinib was compared in 231 patients (39 with deletions and 192 patients without deletions). No survival differences were seen (P = .17). (B) Progression-free survival was compared in 207 patients (35 with deletions and 172 patients without deletions). Patients with deletions had a significantly shorter time to disease progression (P = .02).