Evaluation of Time-to-onset and Outcome of Cardiac Adverse Events Related to Pembrolizumab Using Post-Marketing Surveillance

Abstract Background Pembrolizumab has been widely used in patients since its release, but information on cardiac Adverse Events (AEs) from pembrolizumab remains lacking, particularly in Japanese populations. Aim The aim of this study is to evaluate time to onset, incidence rates, and outcomes for pembrolizumab-induced cardiac AEs in patients with cancer using the Japanese Adverse Drug Event Report database. Method We analysed data for the period from April 2004 to March 2022. Data on cardiac AEs were extracted and relative risks of AEs were estimated using the reporting odds ratio. Results We analysed 2,021,907 reports and identified 15,306 reports of AEs caused by pembrolizumab. Of these, 399 cardiac AEs were associated with pembrolizumab. Signals were detected for six cardiac AEs: myocarditis, immune-mediated myocarditis, pericardial effusion, cardiac tamponade, pericarditis, and pericarditis malignant. A histogram of median times to onset showed occurrence from 33 to 138 days, but some cases occurred even more than 1 year after the start of administration. Among these, myocarditis was the most frequently reported (27.1%), with fatal cases also reported. Conclusion This study focused on cardiac AEs caused by pembrolizumab as post-marketing AEs. Patients should be monitored not only at the time of administration, but also over time for signs of these AEs, especially myocarditis, as some patients may have serious outcomes.