Efficiency of CAR-T Therapy for Treatment of Solid Tumor in Clinical Trials: A Meta-Analysis

Background. Chimeric antigen receptor T (CAR-T) cell therapy has achieved unprecedented success among hematologic tumors, but its role in treating solid tumors is still unclear. Methods. A comprehensive search of electronic databases up to June 1, 2018, was carried out by two independent reviewers. We included studies which focused on the association between CAR-T cell therapy and patient response rate and survival time in solid tumors. Results. 22 studies with 262 patients were included in our meta-analysis. The overall pooled response rate of CAR-T cell therapy was 9% (95% confidence interval (CI): 4-16%). Subgroup analysis (analyses) demonstrated that CAR-T therapy could perform its best therapeutic effect on neuroblastoma, while barely works among gastrointestinal malignancies. Moreover, the treatment efficacy was not significantly impacted by different treatment strategies (lymphodepletion before T cell infusion, transfection method, cell culture duration, persistence of CAR-T cells, transfection efficacy, total cell dose, and administration of IL-2). Only T cell culture duration was associated with better clinical prognosis. Conclusions. Although CAR-T cell therapy did not have satisfactory responses in solid tumors, researchers were still holding an optimistic attitude towards its future efficacy with more modifications of its structure.