Characterization of Cardiovascular Events and Prognosis in Immune Checkpoint Inhibitor-Related Myocarditis

Area of Science:

• Cardiology
• Oncology
• Immunology

Background:

• Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment.
• Immune checkpoint inhibitor-related myocarditis (ICIrM) is a rare but serious adverse event.
• Understanding the long-term cardiovascular implications of ICIrM is crucial.

Purpose of the Study:

• To determine the incidence, timing, and characteristics of ICIrM.
• To evaluate associated cardiovascular events and mortality at 3-year follow-up.
• To identify risk factors and outcomes in patients with ICIrM.

Main Methods:

• Retrospective review of 5423 patients treated with ICIs from 2011-2022.
• Propensity score-matched control group (1:4 ratio) identified.
• Manual curation of baseline characteristics, cardiovascular events, and mortality over 3-year follow-up.

Main Results:

• ICIrM occurred in 1.1% of patients (59/5423).
• Median time to ICIrM diagnosis was 44 days.
• ICIrM significantly increased risk of cardiac death (HR 34.0), MACE (HR 5.0), ventricular tachycardia (HR 12.3), and complete heart block (HR 2.3).
• Most events occurred within 120 days of ICIrM diagnosis.
• Triple-M syndrome (myocarditis, myasthenia, myositis) associated with increased all-cause mortality (HR 2.1).

Conclusions:

• ICIrM is associated with a substantial increase in cardiovascular events and mortality.
• Cardiovascular events predominantly manifest within the first 4 months post-diagnosis.
• Extended follow-up is essential for characterizing and managing ICIrM complications.