Safety and Efficacy of Early Second Infusion of Axi-cel Based on ctDNA for R/R Large B - Cell Lymphoma

"Drug: Axicabtagene Ciloleucel (CD19 CAR-T cells), 2×106 cells/kg, IV infusion at Day 0 and 30-90 days post-first infusion.~Drug: Cyclophosphamide (500 mg/m²) + Fludarabine (30 mg/m²), IV on Days -5, -4, -3.~Procedure: ctDNA monitoring via liquid biopsy at pre-lymphodepletion and Months 1, 2, 3, 6, 9, 12 post-infusion."