Anti-CD 19 and Anti- CD 20 Chimeric Antigen Receptor-Modified T Cells for B-Cell Malignancies: A Systematic Review and Meta-Analysis

Background:

Chimeric antigen receptor (CAR) modified T cells targeting CD19 and CD20 have shown activity in Phase I, II trials of patients with hematological malignancies. CD19 and CD20 targeted CAR constructs from several different institutions have demonstrated consistently high anti-tumor efficacy in children and adults with relapsed B-cell acute lymphoblastic leukemia (B-ALL), chronic lymphocytic leukemia (CLL) and B-cell non-Hodgkin lymphoma (B-NHL). We conducted a systematic review and meta-analysis of all published clinical trials studying the role of efficacy as well as safety of CD-19 and CD-20 CAR-T therapy for B-cell hematologic malignancies.

Methods:

Literature search was performed using MEDLINE (Ovid SP and PubMed), EMBASE, The Cochrane Library, Scopus and Web of Science. We conducted meta-analysis using random effects model using Comprehensive Metaanalysis 3.0. Heterogeneity was assessed using Q-statistic and it was quantified using I²statistic.

Results:

After a comprehensive literature search 4476 studies were identified and finally 15 eligible studies involving 121 patients were included in the final systematic review. The infused CAR T-cell dose was in the range of 0.76 x 10⁶ to 3 x 10⁷ cells/kg in seven trials and in the range of 0.8 x 10⁷ cells to 3.3 x 10⁹ cells/m²in 6 trials. Among 106 patients, the overall response to treatment after CAR T-cell infusion were 33% complete remission (CR), 30 % partial remission (PR), 21% stable disease (SD), and 8% progressive disease (PD). Three studies described response to immunotherapy as minimal residual disease negative (MRD-) and as no evidence of disease (NED) and after including it, the overall CR was 38%. Major adverse events included fever (38%), hypotension (23%), chills (29%), rigor (28%), fatigue 17% and dyspnea 10%. One patient died from cytokine release syndrome, which is potentially serious complication. Neurological symptoms require prompt recognition and management.

Conclusion:

CAR T cell therapy is a promising treatment for refractory and relapsed hematological malignancies. The durable responses of CAR T cell therapy help integrate it in standard treatment protocols. Patients who are refractory to standard salvage chemotherapy or relapse after allo - HSCT have overall poor prognosis and can potentially achieve remission again with CAR T cell therapy.