Survival outcomes. Overall survival (A) and event-free survival (B) in the 39 patients receiving imatinib, and response duration (C) in the 26 patients who achieved ≥ MR/SD (minor response or stable disease with steroid sparing) at 6 months according to Center Response. OS was measured from the initiation of imatinib until death, and EFS was measured from the initiation of imatinib until death, secondary neoplasia, or treatment failure. Response duration (RD) was defined as time from response evaluation at 6 months to loss of response (NR/PD) in patients achieving ≥ MR/SD at this time point, according to Center Response. Among patients with SD, only those with stable pulmonary function and a >50% decrease in steroid dose were included.²²