OS, CI of CCyR, and CI of CMR according to the BCR-ABL1 transcript level at 3 and 6 months. (A) The 8-year probability of OS. The 181 (66%) imatinib-treated patients with low transcript numbers both at 3 months (<9.8%) and at 6 months (<1.67%) had an OS of 93.5% and constitute the reference category for this analysis (group A). The 57 patients (21%) who had high transcript levels on both occasions (group B) had an OS of 55.6% (P < .001). The 30 patients (11%) with low transcript levels at 3 months but high transcript levels at 6 months (group C) had an OS of 92.4% (P = .78). The 6 patients (2%) who had high transcript levels at 3 months but low levels at 6 months (group D) had OS= 83.3% (P = .23). The P value for the comparisons between groups B and C was P = .004 and between groups B and D was P = .39. Similar results were found when we used PFS as outcome criterion; namely, the PFS for patients in the group A was 93.0%. Group B patients had a PFS of 52.5% (P < .001). Group C patients had a PFS of 92.4% (P = .72) and group D patients had a PFS of 83.3% (P = .31). The P value for the comparisons between groups B and C was .001 and between groups B and D was .26. (B) The 8-year CI of CCyR. The 8-year CI of CCyR for patients in groups A, B, C, and D (defined above) was 100%, 14.9% (P < .001), 99.5% (P = .001), and 33.3% (P < .001). The P value for the comparison between groups B and C was <.001 and between groups B and D was .09. (C) The 8-year CI of CMR. We classified the imatinib-treated patients according to whether the transcript level at 3 and 6 months was higher or lower than the previously reported cut off that optimally predicts for this outcome (0.61% for 3 months and 0.21% for 6 months). A total of 34 patients(13%) had low transcripts both at 3 and 6 months, and their 8-year CI of CMR was 75.5%. The CI of CMR for the 6 patients (2%) who had low transcript levels at 3 months but high levels at 6 months was 100% (P = .8). The 193 (70.5%) patients who had high transcript levels on both occasions had a CI of CMR of 1.25% (P < .001) and the 40 (14.5%) patients who had high transcript levels at 3 months but low levels at 6 months had a CI of CMR of 3.6% (P < .001).