The World Health Organization (WHO) has a global reporting system VigiAccess for drug-related adverse events. Emerging from this database is an alarming number (n=101) of life-threatening myocarditis cases following immunotherapy, 46 resulting in death. 85 of these 101 cases occurred with anti-PD-1 therapy either alone (n=58) or in combo with anti-CTLA-4 (n=27). What’s even scarier: two-thirds of cases with available dosing info occurred after only 1-2 doses and three-quarters were on zero other medications for cardiovascular or diabetic indications. TBL: Add myocarditis to the list of lethal autoimmune events that can happen early and among otherwise healthy patients receiving immunotherapy.