Clinical outcomes of chimeric antigen receptor T cell therapy in 21 patients with Relapse/Refractory Ileocecal B cell lymphoma

Objective To evaluate the efficacy, safety, and prognostic factors of chimeric antigen receptor-T cell (CAR-T) therapy in patients with relapsed/refractory ileocecal lymphoma and provide evidence for salvage therapy. Methods This retrospective analysis included 21 patients with ileocecal lymphoma (IC group) and 23 matched patients without ileocecal lymphoma (non-IC group) who received CAR-T therapy between June 2014 and August 2024. Baseline characteristics, genetic mutations, CAR-T cell kinetics, treatment response, overall survival (OS), and progression-free survival (PFS) were assessed. Prognostic factors were identified using Kaplan–Meier analysis, Cox regression, and least absolute shrinkage and selection operator models. Results The IC group showed a significantly lower 3-month objective response rate (57.14% vs. 86.96%, P = 0.042) and shorter median PFS (5 months vs. 27 months, P = 0.0007) than the non-IC group. CAR-T cell expansion was higher in the IC group (CD19 Cmax: 55774 vs. 3811, P = 0.014), but persistence was similar. The safety profiles of CRS and ICANS were comparable across groups (P > 0.05). Multivariate analysis revealed poor 3-month treatment response (hazard ratio [HR] = 32.075, P = 0.015) and higher pre-treatment lines (HR = 8.6, P = 0.036) as independent risk factors for PFS. Delayed B-cell recovery and low baseline lymphocyte counts were associated with poorer OS. Conclusion CAR-T therapy is feasible and safe for relapsed/refractory ileocecal lymphoma, but short-term efficacy is inferior to that in the non-IC group. High CAR-T expansion did not improve long-term outcomes. Early response assessment (3 months), baseline lymphocyte levels, and B-cell recovery are critical prognostic indicators, suggesting the need for optimised treatment timing and combination strategies to enhance efficacy.