[Unexpected adverse events of immunotherapies in non-small cell lung cancer: About 2 cases]

Area of Science:

• Oncology
• Immunology
• Neurology

Background:

• Programmed death receptor 1 (PD1) inhibitors, like nivolumab, are vital immunotherapies for non-small cell lung cancer (NSCLC).
• While known for toxicities such as colitis, endocrinopathies, and pneumonitis, rare immune-mediated adverse events are increasingly reported.
• These toxicities can occur even in patients without a prior history of immune dysregulation.

Observation:

• Two cases of rare nivolumab-associated toxicities are presented in patients without a history of immune disorders.
• Case 1: A 79-year-old patient developed muscle weakness, diagnosed as myositis with elevated CPK and myasthenia symptoms after nivolumab treatment for large-cell carcinoma.
• Case 2: An 82-year-old patient with EGFR-mutated bronchial adenocarcinoma experienced shoulder/hip pain and fatigue, diagnosed as systemic lupus erythematosus (SLE) under nivolumab therapy.

Findings:

• Myositis, confirmed by biopsy, and myasthenia gravis symptoms were observed in one patient.
• Systemic lupus erythematosus was diagnosed in the second patient.
• Both patients' symptoms resolved after nivolumab discontinuation and initiation of systemic corticosteroid therapy.

Implications:

• Clinicians should be vigilant for immune-mediated toxicities, including rare presentations like myositis and SLE, during PD1 inhibitor therapy.
• Discontinuation of anti-PD1 therapy and prompt corticosteroid administration are essential for managing these adverse events.
• Careful collegial discussion is needed regarding retreatment with PD1 inhibitors after symptom resolution, especially if alternative therapies are limited.