Relapse-free survival in adolescent and adult patients with ALL according to immunophenotypic MRD level at day +35 of induction therapy. Median RFS of 42 months for patients with low MRD levels (< 0.05%; n = 43; gray line) versus 16 months for patients with high MRD levels (≥ 0.05%; n = 44; black line) (P = .001).