Steroid-dependent polyarthritis induced by immune checkpoint inhibitor therapy successfully treated with bimekizumab.

ABSTRACT

Immune checkpoint inhibitors (ICIs) are an integral part of modern-day cancer therapy. Along with a greatly improved antitumor response come a number of immune-related adverse events (irAEs), musculoskeletal irAEs rank among the less frequent manifestations. The mechanisms behind these events are poorly understood, and so far clear guidelines for therapeutic management beyond treatment with glucocorticosteroids are lacking. We present the case of a 72-year-old patient who developed a severe ICI-induced polyarthritis that could not be controlled by glucocorticosteroids. We initiated an immunomodulating therapy with the IL-17A/F/AF-inhibitor bimekizumab, which lead to a full clinical and sonographic remission.

In advanced stages, melanoma requires systemic therapy. Immune checkpoint inhibitors (ICIs) allow the body's own defense system to fight the cancer. They are an important part of this therapy. As a downside, they can cause immune-related side effects such as pain and inflammation in the joints. These are often chronic and have a great effect on the patient's quality of life. We therefore need long-term treatments that do not interfere with the intended antitumor response and allow the patients to live a nearly normal life. Corticosteroids often offer short-term relief. Patients whose symptoms cannot be steadily controlled by corticosteroids alone often need further medication. These substances aim to change the activity of the immune system. We present the case of a 72-year-old patient with a melanoma that had spread to other parts of the body. He suffered from great pain caused by inflammation of many of his joints. We could not control his symptoms using corticosteroids, so we decided to use the IL-17 blocker bimekizumab. This treatment is approved for psoriasis associated joint inflammation, inflammations of the spinal joints and psoriasis. This led to a rapid relief of joint pain and stiffness and allowed us to continue the melanoma therapy. The patient further continued to show a good antitumor response. As of this writing, the scans show no signs of cancer.