Second Primary Cancer After Chimeric Antigen Receptor-T-Cell Therapy: A Review

The commercialization of chimeric antigen receptor-T-cell (CAR-T) therapy has changed the landscape of treatment of hematological cancers. Numerous studies from the early 2000s paved the way for cell-based targeted therapeutics, which have been established as practice-changing therapies in lymphoma, leukemia, and multiple myeloma. However, there has been some recent concern about the risk for second primary cancers (SPCs).

Multiple cases of SPCs arising after CAR-T therapy have been reported to the US Food and Drug Administration. Most SPCs have been negative for the chimeric antigen receptor transgene, with rare reports of transgene-positive cancers. This review summarizes the most salient literature on epidemiology and pathobiology of SPCs after CAR-T therapy. Additionally, a discussion is provided on potential mitigation strategies for SPCs after CAR-T therapies.

The results of this review suggest that there are limited data to suggest that inadvertent transgene insertion is associated with SPCs in the post-CAR-T setting. Nonetheless, evidence-based practical solutions and scientific strategies for risk mitigation can be implemented. These include optimization of T-cell manufacturing, application of safer synthetic immunobiology, and implementation of high-fidelity genomic testing, including baseline screening for clonal hematopoiesis. These strategies may inform optimal design of the next generation of CAR-T products that confer minimal risk for SPCs such that the risk-benefit profile remains favorable to proceed with CAR-T administration for eligible patients.