[A multicenter phase 2 trial in children and young adults with newly diagnosed T-ALL: ALL-T11/ T-ALL-211-U from the Japan Children's Cancer Group and the Japan Adult Leukemia Study Group].

T-cell acute lymphoblastic leukemia (T-ALL) accounts for approximately 10-15% of childhood ALL, with its incidence increasing during the adolescent and young adult (AYA) period. The Japan Children's Cancer Group (JCCG) and the Japan Adult Leukemia Study Group (JALSG) conducted the ALL-T11/T-ALL-211-U clinical trial in newly diagnosed T-ALL patients under 25 years of age. The treatment protocol for this trial, which was based on the AIEOP-BFM-ALL 2000 trial, incorporated nelarabine and included dexamethasone induction, intensified L-asparaginase, and extended intrathecal therapy. This study aimed to improve outcomes while reducing the need for cranial irradiation and hematopoietic stem cell transplantation. The results showed a 3-year event-free survival of 86.4% and an overall survival rate of 91.3%, with an acceptable adverse event profile. The outcomes of this trial treatment compared favorably with those of recent clinical trials, with notable improvement achieved in outcomes of childhood T-ALL in Japan. The JCCG and JALSG are now jointly conducting the ALL-T19 trial based on these findings.