Giant cell arteritis associated with PD-1 inhibition

Area of Science:

• Rheumatology
• Oncology
• Immunotherapy

Background:

• A 50-year-old woman with metastatic lung adenocarcinoma was treated with pembrolizumab, a programmed death 1 receptor (PD-1) antagonist.
• Two months after initiating PD-1 antagonist therapy, she presented with new-onset polyarthralgia and headache.

Observation:

• Physical examination revealed left temporal artery tenderness and hand synovitis.
• Ultrasound imaging demonstrated an enlarged temporal artery.

Findings:

• The patient was diagnosed with giant cell arteritis, likely triggered by PD-1 antagonist therapy.
• Initial treatment with corticosteroids led to symptom resolution.
• Due to steroid side effects, methotrexate was introduced while continuing PD-1 antagonist therapy.

Implications:

• This case highlights a potential association between PD-1 antagonist therapy and the development of giant cell arteritis in cancer patients.
• Management involved a multidisciplinary approach with rheumatology and oncology, balancing autoimmune side effects with cancer treatment.
• Continued PD-1 antagonist therapy was feasible with appropriate management of the autoimmune complication, maintaining oncologic stability and improving functional status.