Efficacy and Safety of CD19-Targeted CAR-T Cell Therapy for Refractory/Relapsed B-Cell Lymphoma: A Single Center of Real World Data

【Abstract】 Objective To investigate the efficacy and safety of CD19-targeted chimeric antigen receptor T cell (CAR-T cell) for refractory/relapsed B-cell lymphoma. Methods The efficacy and safety of CD19-CAR-T cells(4-1BB costimulatory domain) in treatment of 12 patients with relapsed/refractory B-cell lymphoma from March 2018 to December 2019 in the Department of Hematology of Guangdong Second Province Hospital were collected analyzed retrospectively. There were 9 patients (75%) with diffuse large B cell lymphoma, 1 patient with blastic variant of mantle cell lymphoma, 1 patient(8.3%) with Burkitt lymphoma, 1 patient with B cell non-Hodgkin lymphoma that cannot be classified. 3 patients (25%) with large mass (≥7.5cm) and 9 patients (75%) with ECOG score ≥2. The number of chemotherapy courses received before transfusion was 4-9, the median number of chemotherapy courses was 7. All 12 patients were autogenous mouse CAR-T cells. Fludarabine + Cyclophosphamide (FC) regimen was used for pretreatment before transfusion, and the number of CAR-T cells was 1 ~ 3.69×10 ⁶/kg. Results All 12 patients received CD19-targeted CAR-T cell therapy. There were 9 patients had treatment response, and the total effective rate was 75%. Among them, there were 3 patients with complete response (CR), with CR rate of 25%, and 6 patients with partial response (PR), with PR rate of 50%. Among the 3 patients with CR remained CR at the follow-up date. Among the 6 patients with PR, 4 showed disease progression in the second month after transfusion, and 2 showed disease progression in the third month after transfusion. All the 9 patients with effective treatment had different degrees of cytokine release syndrome (CRS), including 3 level-1 CRS, 4 level-2 CRS, and 2 level-3 CRS. Two of them had grade 2 CRES, and all CRS and CRES were controlled after treatment with IL-6 receptor antagonists and glucocorticoids. None of the 3 patients failed to respond to treatment had CRS. Conclusion CD19-targeted CAR-T cell immunotherapy has been shown to be effective in CD19-antigen positive B-cell lymphoma, and adverse CRS reactions during treatment can be controlled after treatment. Patients who obtained CR seemed to be able to maintain long-term CR status, while patients who failed to obtain CR showed disease progression within a short period of 3 months, suggesting that patients who obtained CR at an early stage could achieve better efficacy. Therefore, how to identify patients who receive CR at an early stage may be a research direction for the clinical application of CAR-T cell immunotherapy in B-cell lymphoma.

【Key words】Chimeric antigen receptor T-cell; Relapsed/refractory B cell lymphoma; Efficacy; Safety; Cytokine release syndrome