Outcomes in Patients With Immune Checkpoint Inhibitor-Related Myopathy and Prolonged Follow-Up

Area of Science:

• Neurology
• Immunology
• Oncology

Background:

• Immune checkpoint inhibitors (ICIs) are crucial cancer therapies.
• Immune-related adverse events (irAEs) are common, with myopathy being a frequent neurologic irAE.
• Long-term outcomes of ICI-related myopathy are not well-established.

Purpose of the Study:

• To evaluate the long-term outcomes of patients diagnosed with immune checkpoint inhibitor-related myopathy.
• To identify factors associated with disease course and prognosis in ICI-related myopathy.

Main Methods:

• Retrospective review of patients with ICI-related myopathy at Mayo Clinic (2013-2024).
• Comparison between patients with at least 6 months of follow-up and those who died within 2 months of onset.
• Analysis of clinical presentation, treatment, and outcomes.

Main Results:

• Eighty-seven percent of patients achieved a favorable outcome (irAE grade ≤2) at last follow-up, with residual symptoms in 48%.
• Most patients showed gradual improvement, even after treatment cessation.
• Male sex, bulbar, and axial involvement were associated with a poorer prognosis.

Conclusions:

• Long-term functional outcomes for ICI-related myopathy are generally favorable, but residual symptoms persist in about half of patients.
• Symptom improvement can continue for over 12 months.
• Identifying specific clinical features can predict a more severe disease course, suggesting atypical pathology in refractory cases.