- A radiation-free chemotherapy-based conditioning before hematopoietic stem cell transplantation (HSCT) associated with poorer outcomes in young patients with acute lymphoblastic leukemia (ALL) vs total body irradiation.
- The trial was stopped early because of futility.
Why this matters
- Findings suggest that irradiation is necessary despite concerns of its side effects.
- Multicenter global FORUM (For Omitting Radiation Under Majority Age) trial.
- 413 children aged ≥4 years with a matched sibling or unrelated donor for HSCT were randomly assigned to either chemotherapy-based conditioning (fludarabine/thiotepa/busulfan or fludarabine/thiotepa/treosulfan) or total body irradiation/etoposide (radiation group).
- Funding: None disclosed.
- 72% of patients had B-cell precursor ALL and 23% had T-cell ALL.
- Intent-to-treat population:
- 2-year OS was 75% in patients assigned to the chemo-conditioning group vs 91% in the radiation group (intention to treat P<.001>
- 2-year cumulative incidence of relapse was significantly higher in the chemo-conditioning group (33% vs 12%; P<.001>
- 2-year event-free survival was higher in the total body irradiation group (86% vs 58%; P<.001>
- 2-year transplant-related mortality was lower in the radiation group (2% vs 9%; P=.02).
- Study stopped because of futility.