EFS and OS in B-cell ALL patients after CD19 CAR T-cell therapy. (A-B) Kaplan-Meier analyses demonstrating better EFS and OS in patients who achieve MRD-negative CR by high-resolution flow cytometry on restaging (black line, n = 45) compared with patients who do not respond (red line, n = 8; P < .0001 and P = .014, respectively; log-rank test). (C-D) In the MRD-negative CR patients who had a leukemic clone detected by HTS (n = 28) before CD19 CAR T cells, absence of the leukemic clone (black line, n = 20) after CAR T cells was associated with significantly better EFS (P = .036) and a trend toward better OS (log-rank test P = .14) compared with those with a persistent leukemic clone (red line, n = 8).