The early achievement of measurable residual disease negativity in the treatment of adults with Philadelphia-negative B-cell acute lymphoblastic leukemia is a strong predictor for survival.
The minimal or measurable residual disease (MRD) status following induction/consolidation chemotherapy is an important prognostic endpoint in adult patients with newly diagnosed acute lymphoblastic leukemia (ALL). However, the optimal time-point (TP) of MRD assessment and its impact on outcome remains unclear. We analyzed 215 patients with newly diagnosed Philadelphia negative B-cell ALL who received intensive chemotherapy and had available MRD assessment by multicolor flow cytometry at two separate TPs; median time to first TP (1TP) and second TP (2TP) were 24 and 110 days, respectively. At 1TP, 148 patients (68%) were MRD negative and 67 (32%) were positive. Of the 148 patients with negative MRD at 1TP, 147 (99%) maintained it through 2TP. Patients who were MRD negative at both TPs, early MRD responders, had the 3-year event-free survival (EFS) and overall survival (OS) rates of 65% and 76%, respectively. Patients with improved MRD status from positive to negative, late MRD responders, had lower 3-year EFS and OS rates, 42% and 58%, respectively (p=0.001). Multivariate analysis showed that KMT2A (MLL) rearrangement and MRD positivity at 1TP were the only factors correlated with worse OS. In conclusion, the earlier achievement of MRD negative remission is a stronger prognostic factor for survival. This article is protected by copyright. All rights reserved.