Associations Between Pre-Existing Autoimmunity and Chimeric Antigen Receptor T Cell Therapy Toxicity for Cancer Treatment.

OBJECTIVE: Chimeric antigen receptor (CAR) T cell therapy is being investigated to treat individuals with autoimmune diseases. Data regarding the safety of CAR T cell therapy in this population are limited. We aimed to assess whether pre-existing autoimmune disease was associated with an increase in major toxicity or hospital length of stay (LOS) among patients receiving CAR T cell therapy for the treatment of hematologic cancer. METHODS: This retrospective cohort study used data from the National Inpatient Sample (2021-2022) to investigate in-hospital outcomes in adult patients receiving CAR T cell therapy. Comparisons were drawn between patients with and without pre-existing autoimmune disease. Multivariable regression models with adjustment for age, sex, race, cancer type, and comorbidities assessed associations with hospital LOS, major toxicity, and inpatient mortality. RESULTS: Among 1,321 patients receiving CAR T cell therapy, 62 (4.7%) had diagnosed autoimmune disease. Patients with pre-existing autoimmunity had a significantly shorter hospital stay compared with patients without, with a mean reduction of 2.1 days (95% confidence interval [CI] 0.5-3.6). Major toxicity was less frequent in patients with pre-existing autoimmunity than patients without (67.7% vs 78.6%, respectively; adjusted odds ratio 0.55; 95% CI 0.31-0.99). Inpatient mortality did not differ significantly between groups. CONCLUSION: Patients with pre-existing autoimmune disease had shorter hospital stays and lower risk of major toxicity following CAR T cell therapy for cancer treatment, offering reassurance as to its safety in this population while providing additional data for research studies of CAR T cell therapy to treat autoimmune diseases.