Abstract 15678: In Patients Treated With Immune Checkpoint Inhibitors, Myocarditis is Infrequent Compared With Other Cardiovascular Events

Abstract

Introduction: Cardiotoxicity with immune checkpoint inhibitor (ICI) treatment has predominantly focused on myocarditis, which has been estimated to affect ~1% of treated patients. To contextualize myocarditis risk in relation to other cardiovascular (CV) events, we explored reporting of myocarditis, heart failure, arterial and venous thrombotic events in ICI-treated cancer patients. Methods: Data from adults treated with ICI between January 2011 and April 2019 were extracted by the University of Colorado enterprise health data warehouse which draws from electronic medical records and claims data. Medical conditions were determined by International Classification of Diseases (ICD) code; analyses was descriptive. Results: Among 1813 ICI-treated patients, mean age (SD) was 62.5 (13.5 years), 41% were women, 90% were white, 6% Hispanic, 2% black, 1% Asian, <1% American Indian/Alaskan native or native Hawaiian/Pacific islander and 1% multiple race. Prior to ICI initiation, 48% had hypertension, 16% diabetes, 11% were current smokers, 46% former smokers, 11% had estimated glomerular filtration rate <60 ml/min/1.73m 2 and 17% reported prior coronary revascularization. The most commonly treated malignancies were melanoma (40%) and lung cancer (31%). 47% of patients received pembrolizumab and 42% received nivolumab, the most often administered ICIs during this time period. Both before and after ICI administration, venous thromboembolism (VTE) and heart failure were the most frequently reported CV events (Figure). After initiation of ICI, myocardial infarction (MI) and stroke were reported for 54 (3.0%) and 73 (4.0%) patients, respectively. Myocarditis was more common after ICI than before ICI initiation (1 vs 9 patients [0.1%vs 0.5%]) but was infrequent compared with other CV events. Conclusions: Arterial and venous thrombotic events and heart failure were much more common than myocarditis in patients treated with ICI.