Prognostic factors in BL. Kaplan-Meier curves of (A) PFS and (B) OS based on remission status at the end of first-line therapy. The 3-year PFS for patients with CR, PR, SD, and PD were 87% (95% CI, 83-90), 33% (95% CI, 12-48), 43% (95% CI, 10-73), and 1% (95% CI, 0-6), respectively; 3-year OS rates were 90% (95% CI, 87-93), 54% (95% CI, 35-68), 51% (95% CI, 12-81), and 11 (95% CI, 5-19), respectively. Kaplan-Meier curves of (C) PFS and (D) OS by the number of adverse prognostic factors (ie, age ≥ 40 years, ECOG PS 2-4, LDH > 3× normal, and CNS involvement at diagnosis). Increasing number of factors presented portended an increasingly poor prognosis: in the derivation cohort, 3-year PFS with 0, 1, or 2 to 4 factors was 91% (95% CI, 84-95), 73% (95% CI, 66-78), and 50% (95% CI, 44-56), respectively (P < .001), and associated 3-year OS rates were 95% (95% CI, 89-98), 77% (95% CI, 71-82), and 56% (95% CI, 49-62), respectively (P < .001). Abbreviations: PR, partial remission; SD, stable disease; PD, progressive disease.