Evolution of CAR-T Therapy: Functional Engineering, Manufacturing Innovation, and Future In Vivo Strategies.

Chimeric antigen receptor (CAR)-T cell therapy has transformed the treatment of hematologic malignancies and established a new paradigm for engineered cellular immunotherapy. However, its broader clinical application remains constrained by complex autologous manufacturing, high cost, limited scalability, variable product quality, suboptimal efficacy in solid tumors, and treatment-related toxicities. To address these challenges, recent advances in CAR-T cell therapy can be viewed across four interconnected dimensions: functional engineering, manufacturing innovation, alternative cell sources, and in vivo CAR programming. Functional engineering includes cytokine-armored, checkpoint-resistant, multi-targeting, and modular or switchable CAR platforms designed to enhance efficacy, persistence, and safety. In parallel, manufacturing innovations such as shortened culture protocols, automated closed systems, and preservation of less differentiated T-cell states aim to improve product potency while reducing production time and complexity. Alternative cell sources, including allogeneic donor-derived and induced pluripotent stem cell (iPSC)-derived platforms, may further enable standardized, scalable, and potentially off-the-shelf therapies. Finally, in vivo CAR programming has emerged as a fourth dimension in which endogenous immune cells are directly engineered within patients using viral or non-viral gene delivery systems. This review summarizes these interconnected advances and discusses how they may collectively shape the next generation of CAR-based immune therapies.