PURPOSE: Total body irradiation (TBI) before allogeneic hematopoietic stem cell transplantation (HSCT) in pediatric patients with acute lymphoblastic leukemia (ALL) is efficacious, but long-term side effects are concerning. We investigated whether preparative combination chemotherapy could replace TBI in such patients.
PATIENTS AND METHODS: FORUM is a randomized, controlled, open-label, international, multicenter, phase III, noninferiority study. Patients 4 years old with high-risk ALL undergoing allogeneic HSCT.