Minimal residual disease level predicts outcome in adults with Ph-negative Bprecursor acute lymphoblastic leukemia

Institut Germans Tries i PujolObjectives: Detectable minimal residual disease (MRD) after therapy for acute lymphoblastic leukemia (ALL) is the strongest predictor of hematologic relapse. This study evaluated outcomes of patients with B-cell precursor ALL with MRD of ≥10−4. Methods: Study population was from ALL study groups in Europe managed in national study protocols 2000-2014. MRD was measured by polymerase chain reaction or flow cytometry. Patients were age ≥15 years at initial ALL diagnosis. Patients were excluded if exposed to blinatumomab within 18 months of baseline or prior alloHSCT. Results: Of 272 patients in CR1, baseline MRD was ≥10−1, 10−2 to <10−1, 10−3 to <10−2, and 10−4 to <10−3 in 15 (6%), 71 (26%), 109 (40%), and 77 (28%) patients, respectively. Median duration of complete remission (DoR) was 18.5 months (95% confidence interval [CI], 11.9-27.2), median relapse-free survival (RFS) was 12.4 months (95% CI, 10.0-19.0) and median overall survival (OS) was 32.5 months (95% CI, 23.6-48.0). Lower baseline MRD level (P ≤ .0003) and white blood cell count