Integrated Radiotherapy-optimized ASCT Sequential CAR-T Therapy for Patients With Relapsed and Refractory B-NHL

This trial will enroll R/R aggressive B-NHL patients aged ≥18 years who have undergone at least two prior lines of systemic therapy. Participants will be stratified into two cohorts based on post-salvage therapy disease status: Cohort 1 (PET/CT-, ctDNA+): Patients will receive low-dose radiotherapy (RT) combined with reduced-intensity SEAM/TB chemotherapy as a conditioning regimen, followed by ASCT and sequential CAR-T therapy. Cohort 2 (PET/CT+, ctDNA+): Patients will receive high-dose RT combined with reduced-intensity SEAM/TB chemotherapy as a conditioning regimen, followed by ASCT and sequential CAR-T therapy. All patients completing the combined ASCT-CAR-T protocol will undergo longitudinal follow-up for safety, efficacy survival outcomes .