Cardiac effects of chimeric antigen receptor (CAR) T-cell therapy in children.

Abstract

10531 Background: Treatment with CAR T-cells targeting CD19 for pediatric leukemia has demonstrated significant efficacy with the principal toxicity being cytokine release syndrome (CRS). However, the cardiac effects related to CAR T-cell therapy have not been systematically evaluated. Methods: A retrospective chart review was performed on a large cohort who received CAR T-cell therapy from April 2012 through September 2016. Baseline oncologic and cardiac characteristics were recorded. Cardiomyopathy was defined as an ejection fraction < 55%, shortening fraction < 28%, or diastolic dysfunction. Primary outcome was cardiac event, defined as need for inotropic support or echocardiographic decline in function. Descriptive and univariate analyses were performed. Results: 93 patients were included [55% male, mean age 11.8 yrs (range 1.7-27.1)]; 98% had B cell ALL. Prior to treatment, 15% had cardiomyopathy and 1 patient had single ventricle Fontan palliation. Cardiac events occurred in 34 (36%) with mean onset 4.8 days (range 1-9) after CAR T-cell infusion, of whom 12 (35%) had abnormal systolic or diastolic function on echocardiogram and 6 (18%) required milrinone for cardiac support. 21 (22%) patients had CRS requiring tocilizumab and vasoactive infusions; there were no cardiac-related deaths. Factors associated with cardiac events included higher pre-treatment blast % on bone marrow biopsy [OR 10.45 (95% CI 3.87-28.22) for blast > 10%; p < 0.001] but not cardiomyopathy (p = 0.356), total body irradiation (p = 0.717) or anthracycline dose (p = 0.711). At discharge, 7 (7.5%) patients had worse cardiac function than at baseline, but only 2 (2%) had persistent cardiac dysfunction by 6 months post-infusion. Pre-treatment factors were not associated with persistent dysfunction. Conclusions: This is the first study to describe the cardiac effects of CAR T-cell therapy in children. CAR T-cell therapy appears to be safe, even in patients with cardiomyopathy. Although one-third experienced a cardiac event, persistent cardiac dysfunction is rare. Children with a pre-treatment blast > 10% were most at risk for cardiac events, a finding that may help identify patients who warrant close observation and early intervention with pressor support.