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 Re-Intensification (fludarabine, dexamethasone, cytarabine, etoposide and asparaginase). Cranial radiation was limited to patients with WBC >=100k/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 for a median of 70 months (range, 14-181 months). Median age at diagnosis was 9 years (range,0.5-17.8 years). Forty-eight patients were diagnosed after September 2014 and received the augmented regimen; their median follow up was 46 months (range,14-74 months). The 5-yr-EFS estimates for patients who received the augmented regimen vs. standard regimen were 87%±4.9% vs 67%±6.8% (p=0.03); and the 5-yr-OS estimates were 87%±5.1% vs. 71%±6.3% (p=0.06) respectively. Treatment related mortality (TRM) were reported in 2 patients treated using our 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.