Abatacept in Immune Checkpoint Inhibitor Myocarditis

The primary aim is to test whether abatacept, as compared to placebo, is associated with a reduction in major adverse cardiac events (MACE) among participants hospitalized with myocarditis secondary to an immune checkpoint inhibitor (ICI). The primary outcome, MACE, is a composite of first occurrence of cardiovascular death, non-fatal sudden cardiac arrest, cardiogenic shock, significant ventricular arrythmias, significant bradyarrythmias, or incident heart failure.