Early post‐induction augmented therapy improves outcome in children and adolescents with T‐cell acute lymphoblastic leukemia

INTRODUCTION: T‐cell acute lymphoblastic leukemia (T‐ALL) accounts for approximately 15% of all newly diagnosed ALL in children and adolescents and is associated with worse outcomes compared to pre‐B ALL. We aimed to decrease T‐ALL relapses by intensifying our regimen. METHODS: Patients with T‐ALL were treated using two different regimens; before September 2014, patients were treated per St. Jude Total XV protocol; subsequently, a major change was adopted by adding two intensive blocks: FLAG and Reintensification. Cranial radiation was limited to patients with WBC ≥ 100 k/μl at diagnosis and/or patients with CNS2/CNS3 status. RESULTS: Between June 2005 and April 2020, a total of 100 patients (76 males) were treated and followed up for a median of 70 months (range 14–181). Median age at diagnosis was 9 years (range 0.5–17.8). Forty‐eight patients were diagnosed after September 2014 and received the augmented regimen; their median follow up was 46 months (range 14–74). The 5‐year‐EFS estimates for patients who received the augmented regimen versus standard regimen were 87% ± 4.9% versus 67% ± 6.8% (p = .03); and the 5‐year‐OS estimates were 87% ± 5.1% versus 71% ± 6.3% (p = .06), respectively. Treatment related mortality (TRM) was reported in two patients treated per standard regimen but none for patients who received the augmented regimen. CONCLUSIONS: We implemented a novel approach with early intensification added to a backbone of modified St. Jude Total‐XV regimen for patients with T‐ALL that resulted in improved outcome with no treatment related mortality.