Published online Jan 6, 2023. doi: 10.12998/wjcc.v11.i1.218
Peer-review started: October 16, 2022
First decision: November 4, 2022
Revised: November 10, 2022
Accepted: December 16, 2022
Article in press: December 16, 2022
Published online: January 6, 2023
Processing time: 80 Days and 18.5 Hours
Immune checkpoint inhibitor (ICI)-induced rheumatic immune-related adverse events (irAEs) have been infrequently reported, and the treatment of severe or refractory arthritis as irAEs has not been established yet.
The patient was a 67-year-old man with a history of well-controlled foot psoriasis who presented with polyarthralgia. He had received pembrolizumab for metastatic gastric adenocarcinoma 2 mo previously. Physical examination revealed erythematous swelling in the distal interphalangeal joints, left shoulder, and both knees. He had plaque psoriasis with psoriatic nail dystrophy and dactylitis in the distal joints of the fingers and toes. Inflammatory markers including C-reactive protein and erythrocyte sedimentation rate were elevated but rheumatoid factor and anticyclic citrullinated peptide antibody were negative. The patient was diagnosed with psoriatic arthritis (PsA) and started on methylprednisolone 1 mg/kg/day after pembrolizumab discontinuation. However, despite 1 wk of methylprednisolone treatment, PsA worsened; hence, leflunomide and methotrexate were started. After 4 wk of steroid treatment, PsA worsened and improved repeatedly with steroid tapering. Therefore, the therapy was intensified to include etanercept, a tumor necrosis factor inhibitor, which ultimately resulted in adequate PsA control.
This is the first report of ICI-induced PsA in a gastric cancer patient. Some rheumatic irAEs with refractory severe arthritis may require disease-modifying anti-rheumatic drugs and long-term management.
Core Tip: Although immune checkpoint inhibitors are being used increasingly and widely, a fair percentage of patients treated with these drugs experience immune-related adverse events (irAEs). Arthralgia and skin lesions are among the most frequent irAEs. However, rheumatic irAEs are underreported and/or misclassified and have been poorly characterized. These rheumatic irAEs are different in simple arthralgia or cutaneous irAEs that they may be requiring long-term management and disease-modifying anti-rheumatic drugs in severe or refractory case. We report a first case of pembrolizumab-induced psoriatic arthritis that was treated with tumor necrosis factor-α inhibitors in a patient with gastric cancer and discuss the treatment course.