Insight into mechanisms associated with cytokine release syndrome and neurotoxicity after CD19 CAR-T cell immunotherapy.

Adoptive immunotherapy with CD19-targeted chimeric antigen receptor (CAR)-T cells has been successful in producing durable remissions in some patients with relapsed or refractory B cell malignancies. Despite the efficacy of CAR-T cell therapy, significant toxicities can occur. Cytokine release syndrome (CRS) and neurotoxicity are the most common toxicities and can range from self-limited fever to life threatening organ damage and death. Understanding the mechanisms underlying these toxicities can help guide and improve outcomes. In this review we describe CRS and neurotoxicity in patients with B cell malignancies treated with CD19 CAR-T cells in pivotal trials, and also provide insight into potential mechanisms associated with these toxicities based on studies conducted in a phase 1/2 clinical trial at the Fred Hutchinson Cancer Research Center.