Chimeric Antigen Receptor T‐Cells ( <scp>CAR</scp> T‐Cells) in Hematological Malignancies: A Systematic Review and Meta‐Analysis of Proportions From Clinical Trials

This meta-analysis examined the safety and efficacy of CAR T-cell therapy in 3281 patients with hematological malignancies enrolled in phase 1/2, 2 and 3 clinical trials, published until July 23, 2025 according to the PRISMA guidelines. All trials involved relapsed/refractory, pretreated individuals. In 11 multiple myeloma trials, CAR T-cell therapy showed significant efficacy, with pooled ORR and ≥CR rates of 89% and 53%, respectively. These responses translated into important survival benefits, with 1-year OS and PFS rates of 84% and 60%, respectively. However, AEs including any-grade CRS, infections and grade ≥ 3 neutropenia emerged in pooled rates of 89%, 46% and 88%, respectively. In 23 trials on high-grade lymphomas, the pooled ORR was 76% and the pooled ≥CR rate 55%. The pooled 1-year OS and PFS rates were 65% and 46%, respectively. Any-grade CRS was prevalent in a pooled rate of 46% and grade ≥ 3 neutropenia in 56%. Data from 16 records investigating CAR T-cells for leukemia yielded pooled ORR and ≥CR rates of 78% and 70%, respectively, with pooled 1-year OS and PFS rates being 61% and 40%, respectively. Similarly to myeloma and lymphoma, any-grade CRS was very common at a pooled rate of 85% and any-grade infections occurred at a pooled rate of 29%. Apart from grade ≥ 3 neutropenia (70%), grade ≥ 3 anemia emerged as an equally common serious hematological AE (69%). In conclusion, CAR T-cells constitute a highly effective therapeutic option for patients with hematological cancer at relapse, but close patient monitoring is essential to address treatment-related toxicities.