Survivorship in CAR T-cell Therapy Recipients: Infections, Secondary Malignancies, and Non-Relapse Mortality

Background: Chimeric antigen receptor (CAR) T cell therapy has significantly advanced the treatment of hematologic malignancies, offering curative potential for patients with relapsed or refractory disease. However, the long-term survivorship of these patients is marked by unique challenges, particularly immune deficits and infectious complications, second primary malignancies (SPMs), and non-relapse mortality (NRM). Understanding and addressing these risks is paramount to improving patient outcomes and quality of life. Summary: This review explores the incidence and risk factors for non-relapse mortality and long-term complications following CAR T cell therapy. Infections are the leading cause of NRM, accounting for over 50% of cases, driven by neutropenia, hypogammaglobulinemia, and impaired cellular immunity. SPMs, including secondary myeloid and T-cell malignancies, are increasingly recognized, prompting the FDA to issue a black box warning, although their direct link to CAR T cells remains disputed. While CAR T cell-specific toxicities like CRS and ICANS contribute to morbidity, they represent only a minority of NRM cases. The management of these complications is critical as CAR T cell therapy is being evaluated for broader use, including in earlier treatment lines and for non-malignant conditions like autoimmune diseases. Key Messages: CAR T cell therapy has revolutionized cancer treatment, but survivorship is complicated by infections, SPMs, and ultimately endangered by NRM. Prophylactic strategies, close monitoring, and toxicity management strategies are key to improving long-term outcomes.