The efficacy and safety of CAR-T therapy in relapsed or refractory multiple myeloma patients: a systematic review and meta-analysis

<b>Objectives:</b> The introduction of novel therapies has markedly improved the prognosis of multiple myeloma (MM), yet relapse remains common. For patients with relapsed or refractory multiple myeloma (RRMM), immunotherapy - particularly chimeric antigen receptor T-cell (CAR-T) therapy - shows significant promise. This review summarizes current evidence on CAR-T efficacy and safety.<b>Methods:</b> We performed a systematic review of studies published between 1 January 2021 and 1 August 2024 in PubMed, Web of Science, and Embase. Of 4,301 articles identified, 29 met inclusion criteria.<b>Results:</b> Our findings demonstrate that CAR-T therapy is highly effective in the treatment of RRMM, with an overall response rate (ORR) of 86%. Among responders, the minimal residual disease (MRD) negativity rate was 78%. The median progression-free survival (mPFS) was 9.88 months, and the median duration of response (mDOR) was 12.17 months. In terms of safety, cytokine release syndrome (CRS) occurred in 83% of patients (any grade), with 5% experiencing grade ≥3 CRS. The incidence of grade ≥3 neurotoxicity (NT) was 2%. Infections were reported in 50% of patients (any grade), with 21% experiencing grade ≥3 infections.<b>Conclusion:</b> This meta-analysis provides robust evidence supporting the clinical application of CAR-T therapy in the management of relapsed or refractory multiple myeloma.