The presence of a kinase domain mutation predicts shorter progression-free survival after imatinib initiation. The cumulative rate of progression-free survival (Kaplan-Meier method) is shown for patients with versus patients without, a detectable KD mutation, detected by 30 months after initiation of imatinib therapy. This 30-month landmark analysis excludes patients with sequencing performed after 30 months, and those with disease progression or last follow-up occurring before 30 months.