Immune-Related Adverse Events with Immune Checkpoint Inhibitors: Arthritis

Immune checkpoint inhibitors (ICI) cause a variety of adverse events due to increased immune activation. Inflammatory arthritis is the most common side effect of ICIs seen by rheumatologists. Inflammatory arthritis can have heterogeneous presentations, but, most commonly, presents as an oligoarthritis or polyarthritis. Tendons may also be involved, and imaging shows a variety of changes, including synovitis, joint effusions, tenosynovitis, enthesitis, tendinitis, and enthesophytes. Treatments include nonsteroidal anti-inflammatory drugs (NSAIDs), systemic corticosteroids, intra-articular corticosteroids, conventional synthetic disease modifying drugs (e.g., methotrexate), and biologics, depending on severity and persistence of the arthritis. More studies are needed, but preliminary data do not show increased tumor progression in patients who require these therapies.