Response to imatinib treatment by Kaplan-Meier analyses. (A) Time to progression (TTP) and overall survival (OS) calculated from the start of imatinib treatment for all 68 patients. Ten patients discontinued therapy to undergo allogeneic transplantation while still in CR and were censored for the TTP analysis at the time of transplantation. Twelve patients underwent transplantation after relapsing on imatinib, either with active disease or after renewed salvage therapy. Estimated median TTP and OS for all patients were 2 months (range, 0.1-14.9 months) and 6.2 months (range, 0.8-33.7 months), respectively. The estimated survival rates for all patients were 33.3% ± 5.8% at 12 months and 22.6% ± 5.4% at 18 months without censoring at the time of transplantation and 31.2% ± 7.2% at 12 months and 21.4% ± 6.8% at 18 months with censoring at the time of transplantation. (B) TTP and OS by BM response after 14 days imatinib therapy. Response duration was significantly longer in patients with a good day 14 marrow response (median TTP, 5.2 months) than in patients with blasts of more than 5% (median TTP, 0.9 months; P < .0001). OS was significantly superior in patients with a good day 14 marrow response (10.5 months versus 4.0 months; P < .0001). (C) Median TTP and OS in patients with an additional Ph or Bcr-Abl signal were inferior to those in patients without extra Ph chromosomes (1.6 months versus 3.2 months [P = .006], and 5.2 months versus 9.6 months [P = .01], respectively). Patients with extra Ph chromosomes and/or Bcr-Abl signals in more than 20% of nuclei had a significantly inferior TTP and OS (1 month and 4.4 months, respectively). Dotted line in panels A and C indicates the 50% level.