A matter of inflammation: CAR T-cell therapy and atrial fibrillation

Abstract Background Chimeric antigen receptor (CAR) T-cell therapy has been revolutionary in the treatment of blood cancers, but has been associated with arrhythmias such as atrial fibrillation (AF). Whether the incidence of AF has changed over time and if contributing risk factors are present remains to be defined. Methods Leveraging the Mayo Electronic Medical Record, we extracted a cohort of patients who underwent CAR T-cell therapy between 2016 and 2022. From this cohort, we identified those who had a diagnosis of AF at any point. We then defined the endpoint of interest as the first episode of new or recurrent AF during or after CAR T-cell infusion. Fine and Gray subdistribution hazard modeling was used to calculate the association of patient characteristics to the endpoint of interest. Variables with P<0.20 in univariate modeling were chosen for the multivariate model. Significance was defined as P<0.05. Results There were 328 patients who underwent CAR T-cell therapy between 2016 and 2022. Of this cohort, 27 (8.2%) patients had a pre-existing diagnosis of AF, of which 6 had recurrence of AF after CAR T (22.2%), while 21 (77.8%) did not. Of the 301 patients without a prior history of AF, 8 (2.7%) patients developed new-onset AF after CAR T. The majority of the 14 new or recurrent AF events (4.3% overall incidence) occurred within 30 days of receiving CAR T (N=10, 71.4%), the remainder after 180 days (Figure 1). No trend in declining incidence over time was noted. Prior AF, neurotoxicity, and inflammation (cytokine release syndrome and macrophage activating syndrome-like (MAS-L)) were strongly associated with the risk of developing new or recurrent AF (Table 1). Only presence of MAS-L remained an independent predictor in the multivariate model (HR 15.4, 95% CI 3.9-61.2, P<0.001). Conclusion AF is mainly seen early following CAR T-cell therapy, and mainly in association with severe inflammatory responses. Early and aggressive treatment of CRS and MAS-L may be recommendable for patients undergoing CAR-T therapy, especially for those with a prior history of AF.