A Retrospective Cohort Study of Chimeric Antigen Receptor T-Cell Therapy in Follicular Lymphoma Patients with or without Histological Transformation

Background: Follicular lymphoma (FL), one of the most common indolent lymphomas, is still classified as an incurable disease. Adverse outcomes in FL frequently occur in patients who experience early relapse or histological transformation to aggressive lymphoma. Chimeric antigen receptor T-cell therapy (CAR-T) has received approval for the treatment of relapsed/refractory B-cell lymphoma. Methods: This retrospective study presents the clinical characteristics and treatment follow-up of 26 patients with transformed or relapsed/refractory FL who received CAR-T therapy. It evaluates the efficacy of CAR-T and assesses treatment lines, LDH levels, remission status before treatment, and the histological transformation of their prognostic impact. Results: Among the 14 transformed FL patients, there was one treatment-related death, the overall response rate (ORR) was 92.0%, with a 2-year progression-free survival (PFS) rate of 66.7% and an overall survival (OS) rate of 73.3%. For the 12 relapsed/refractory FL patients, the ORR was 100.0%, with a 2-year PFS rate of 75.0% and an OS rate of 100.0%, which is lower than that for transformed FL. A favorable remission state before CAR-T treatment correlated with improved PFS (P =0.009). Compared to transformed patients, those with relapsed/refractory FL exhibited better OS following CAR-T treatment (P =0.04). Conclusion: CAR-T therapy demonstrates significant efficacy and good safety for treating relapsed/refractory follicular lymphoma and transformed lymphoma. Further research should focus on identifying prognostic factors, extending remission duration, and preventing recurrence.