e21047 Background: Patients (pts) with lung cancer and other cancers treated with immune checkpoint inhibitors (ICI) may experience immune related adverse events (irAE). These can present with variable severity and with single- or multi-organ involvement including pneumonitis, colitis, hepatitis, and myocarditis/pericarditis. The incidence of myocarditis has been reported between 0.06% and 2.4% and is associated with a high mortality (25% to 50%). This retrospective review of real-world data (RWD) investigates myocarditis as a high-grade adverse event in pts with lung cancer treated with ICIs. Methods: Pts were identified and characterized using RWD in the Syapse Learning Health Network platform from 2010 to 2020 at Advocate Aurora Health Care. Eligible pts included: ≥18 years old; histologically confirmed NSCLC; and myocarditis diagnosis by ICD codes. Additional chart review was performed to confirm timing of ICI treatment and myocarditis. All pts identification and review were performed after IRB review. Results: 12,686 pts with non-small cell lung cancer were eligible for review. The median age at diagnosis was 70; 54% were female; 86% were White and 12% were Black; 1,975 (15.6%) were treated with an ICI and of those 4 cases (0.2%) of myocarditis were identified. All 4 pts were White females, ages 46, 59, 65, and 74 years. Pathology included lung adenocarcinoma (3) and an undifferentiated lung carcinoma (1). All pts had metastatic disease, and none had a prior history of cardiac disease. ICIs were pembrolizumab (2), durvalumab (1), and nivolumab (1). Median time from initial dose of ICI to diagnosis of myocarditis was 62 days [range: 42-185]. All 4 pts presented with chest pain and elevated troponin T [median 0.07 ng/ml (range: 0.06-0.08)]. All pts had echocardiography at the time of diagnosis, and 2 pts had cardiac MRI that confirmed myocarditis. 3 pts were treated with a prednisone taper. 1 pt died of recurrent congestive heart failure and ventricular tachycardia despite rescue attempt with high dose corticosteroids. 2 pts had additional concomitant irAEs of hypothyroidism/colitis, and thyroiditis/pneumonitis, respectively. Conclusions: Many irAEs are reversible. This RWD analysis confirms that clinically evident myocarditis is a rare but serious adverse event of ICI therapy. Early consideration, diagnosis, and intervention may help prevent poor outcomes. Termination of ICI therapy along with initiation of corticosteroids constitute the current standard of management. Further research is warranted to better identify high risk groups, surveillance measures, and improved management of ICI associated myocarditis.
1003P Expression by immunohistochemistry of p53 tumor suppressor protein as a predictive biomarker of response to immune checkpoint inhibitors in non-small cell lung cancer
