Myocarditis, Myositis, and Myasthenia Gravis Overlap Syndrome Associated with Immune Checkpoint Inhibitors: A...

Area of Science:

• Oncology
• Immunology
• Neurology

Background:

• Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy.
• However, ICIs can induce immune-related adverse events (irAEs).
• A rare but severe irAE is the overlap syndrome of ICI-associated myocarditis, myositis, and myasthenia gravis (MMM).

Purpose of the Study:

• To systematically review and highlight the clinical implications of MMM syndrome.
• To emphasize the importance of recognizing MMM in emergency department settings.

Main Methods:

• A systematic review of PubMed and Embase databases was conducted.
• Inclusion criteria required the presence of myocarditis, myositis, and myasthenia gravis associated with ICI use.
• Data extraction and synthesis were performed using the Rayyan web application.

Main Results:

• Fifty cases of MMM syndrome were identified, primarily associated with melanoma, lung, and renal cancers.
• The in-hospital mortality rate was 38.0%.
• Common symptoms included ptosis (58%), dyspnea (48%), diplopia (42%), and myalgia (36%), with a median onset of 21 days after ICI initiation.

Conclusions:

• ICI-associated MMM syndrome is a rare, potentially fatal complication requiring urgent recognition and management in emergency departments.
• Corticosteroids should be administered promptly upon suspicion, pending confirmation.
• Multidisciplinary collaboration and further research into MMM's specific cancer and ICI associations are essential for improved risk assessment and treatment strategies.