CD19 and acute lymphoblastic leukemia: However, observational multicenter cohorts illustrate outcome variability, with a recent real-world cohort of CD19 CAR-T in B-ALL treated at U.S. and German centers reporting a day-90 overall response rate of 58.1% and complete response rate of 47.6% (5), underscoring the influence of patient selection, prior therapies, and supportive care factors on real-world effectiveness.