Chimeric antigen receptor T-cell therapy in multiple myeloma in 2026: approved indications, long-term outcomes, toxicity, sequencing, and emerging platforms: a narrative review

CAR T-cell therapy has moved from a late-line option to an earlier treatment platform for selected patients with relapsed/refractory multiple myeloma. This narrative review summarizes the 2026 evidence base for approved BCMA-directed products, long-term outcomes, real-world reproducibility, toxicity, sequencing, special populations and emerging platforms. Ciltacabtagene autoleucel (cilta-cel) is approved after at least one prior line in lenalidomide-refractory disease and is supported by progression-free and overall survival benefit in CARTITUDE-4 and by 5-year CARTITUDE-1 follow-up showing multiyear treatment-free control in a subset of patients. Idecabtagene vicleucel (ide-cel) remains a validated option for selected patients after at least two prior lines, supported by KarMMa-3 and real-world data. Safety assessment must extend beyond CRS and ICANS to delayed neurotoxicity, ICAHT, infections, hypogammaglobulinemia, IEC-enterocolitis, IEC-HS and secondary T-cell malignancy surveillance. Post-BCMA relapse requires phenotype-based restaging and careful sequencing with BCMA- and non-BCMA-directed agents. Emerging strategies, including GPRC5D-directed CAR T cells, anito-cel, AZD0120/GC012F, allogeneic and in vivo platforms, are promising but remain evidence-level dependent. The review emphasizes risk-adapted monitoring and implementation priorities for Polish centers.