CAR-T Therapy: Molecular Fundamentals, Clinical Challenges, and Emerging Perspectives

Introduction: chimeric antigen receptor (CAR)-T cell therapy has transformed the treatment of hematologic malignancies, establishing a new paradigm for personalized cellular immunotherapy. Despite remarkable clinical success, its broader application remains limited by biological, logistical, and safety-related challenges. Methods: this review synthesizes current evidence on the molecular foundations of CAR-T cell biology, integrating insights from preclinical studies and clinical trials. We analyze receptor design, co-stimulatory signaling, manufacturing strategies, and emerging engineering approaches aimed at improving efficacy and safety. Results: advances in CAR design and manufacturing have led to multiple FDA approvals in B-cell leukemias, lymphomas, and multiple myeloma. However, key obstacles persist, including antigen escape, T-cell exhaustion, limited persistence, neurotoxicity, and on-target/off-tumor effects. Emerging strategies—such as genome editing, allogeneic and in vivo CAR-T generation, transcriptional and metabolic reprogramming, and synthetic biology circuits (including SynNotch, SNIPR, and logic-gated CARs)—are demonstrating promise in overcoming these limitations. In parallel, conformation-specific target discovery and the use of natural ligands are expanding the scope of actionable antigens. Discussion: collectively, these innovations are reshaping CAR-T therapy into a more modular, programmable, and controllable platform. By addressing resistance mechanisms and toxicity, next-generation CAR designs aim to improve durability and safety while enabling more precise immune activation. Conclusion: continued integration of molecular engineering, systems biology, and synthetic immunology is poised to expand the therapeutic reach of CAR-T cells beyond hematologic malignancies, opening new opportunities in solid tumors and immune-mediated diseases.