Effect of dose-optimized imatinib (IM) 800 mg on deep molecular responses (CMR 4.5) and prediction of survival: Results from the randomized CML-study IV.

7051 Background: Since complete molecular remission (CMR 4.5) defines a subgroup of patients who may stay in remission even after discontinuation of treatment, we analysed whether CMR 4.5 is reached faster with dose optimized IM 800 mg and whether the achievement of CMR 4.5 at specified points in time results in better survival than the achievement of less deep remissions. Methods: Confirmed CMR 4 and CMR 4.5 are defined as ≤ 0.01% BCR-ABL IS or ≥ 4 log reduction and ≤ 0.0032% BCR-ABL IS or ≥ 4.5 log reduction, respectively, from standardized baseline as determined by real-time PCR in 2 independent analyses. Details on CML-Study IV have been published (Hehlmann et al., JCO 2011). Cumulative incidences were estimated under consideration of competing risks. Landmark analyses were performed to evaluate the prognostic impact of different remissions at 4 years on survival. Results: Of 1551 randomized patients with newly diagnosed chronic phase CML 1525 were evaluable. Median age was 52 years, 88% were EUTOS lo...