The 21st International ``Ponte di Legno'' Childhood Acute Lymphoblastic Leukemia Workshop Report: Progress and...

The 21st Ponte di Legno Working Group meeting convened in Orlando, USA, on December 4-5, 2025, bringing together leading childhood acute lymphoblastic leukemia (ALL) investigators from major global consortia. In response to the transformative advances in childhood ALL treatment, particularly the integration of immunotherapy into frontline therapy, the group revisited and updated its mission statement. The revised mission emphasizes collaborative studies on rare leukemia subsets, harmonized toxicity reporting, particularly for immunotherapy-related toxicities, and unrestricted worldwide collaboration. In addition, sharing data and strategies for integrating novel agents will be integral to optimizing future trial design. Key scientific topics included rare genetic subgroups, T-cell ALL genomics, treatment-related toxicity benchmarking, and central nervous system (CNS) disease management challenges. A major focus was immunotherapy integration into frontline therapy, particularly blinatumomab as an emerging standard of care and inotuzumab ozogamicin as an investigational agent, and their potential to enable chemotherapy de-escalation. Additional discussions addressed immunotherapy-specific toxicities. The integration of immunotherapy into frontline ALL therapy represents a paradigm shift with potential to improve outcomes while reducing treatment burden. However, careful attention to CNS disease control, emerging toxicities, and preservation of the remarkable achievements in childhood ALL therapy remains essential as the field advances.