Kaplan-Meier estimate of event-free survival of patients with prednisone poor-response and/or nonremission on day 33 in the trials ALL-BFM 86, 90, and 95. All patients were treated in the HR arm of the respective trial. Log-rank tests: ALL-BFM 86 versus 90, P = .029; ALL-BFM 86 versus 95, P = .14; ALL-BFM 90 versus 95, P < .001. 6y-pEFS indicates probability of event-free survival at 6 years; SE, standard error.