Cardiomyopathy among recipients of immune checkpoint inhibitor therapy: A prospective study.

e24025 Background: Patients treated with immune checkpoint inhibitors (ICI) may develop cardiomyopathy, but data are limited on the rate of cardiomyopathy incidence. The aim of this study was to assess the occurrence of cardiomyopathy among ICI recipients. Methods: In this prospective surveillance study, echocardiograms and EKG were performed at baseline, and quarterly during the first year of ICI therapy. New or worsening cardiomyopathy was defined as left ventricular ejection fraction (EF) decline of > 10% from baseline to < 50%. B-type natriuretic peptide (BNP) and troponin were assessed weekly during the first three weeks of ICI therapy. Subsequent troponin for myocarditis assessment was tested as needed per treating oncology team. Results: A total of 23 patients were enrolled with mean age 73±10 years, 35% female, 74% Caucasian, and body mass index 31±7 kg/m2. Cardiovascular risk factors included hypertension (86%), diabetes mellitus (29%), myocardial infarction (19%) and smoking (10%), and prior radiation treatment (30%). Malignancies included lung cancer (50%), renal cell carcinoma (14%), and Merkel cell carcinoma or urothelial carcinoma (9% each). ICI regimen included pembrolizumab (48%), nivolumab (43%), and ipilimumab or atezolizumab (4% each). There was no change in weekly troponin or BNP, or quarterly QRS duration on EKG, and no myocarditis cases were observed. Between baseline and at 1-year since ICI therapy initiation, there was no change in QRS duration on EKG, as well as no change in median LVEF (59% IQR 46-67 vs 61% IQR 58-65, p = 0.48), or global longitudinal strain (18% IQR 15-20) vs 19% IQR 18-21, p = 0.11). New cardiomyopathy occurred in 1 (4%) patient at 3 months following ICI initiation with LVEF drop from 53% to 38% and without troponin elevation to suggest myocarditis, corresponding to an incidence rate of 43.5 cases per 1000 person-years of observation. Conclusions: In this prospective surveillance study, new cardiomyopathy was observed after ICI treatment, although the incidence was low. Larger studies are needed to confirm these findings.