This is a study of 30 patients with immune checkpoint inhibitor induced inflammatory arthritis. Their clinical features and relationship to immunotherapy regimen were evaluated, as was the course of their arthritis.
Why was this study done?
New cancer therapies called immune checkpoint inhibitors (ICI) work by activating a patient’s own immune system to fight their cancer. Unfortunately, ICI therapy can also activate the immune system to attack healthy tissues and cause side effects like inflammatory arthritis. We wanted to further study the unique features of arthritis that can be caused by ICI therapy.
How was this study done?
This was a study at the Johns Hopkins Arthritis Center evaluating the clinical course of patients seen for inflammatory arthritis induced by ICI therapy. Only patients who received the following immune checkpoint inhibitors were included in the study: anti-CTLA-4/anti-PD-1 combination therapy or anti-PD-1/anti-PD-L1 monotherapy.
What were the major findings?
Patients treated with combination ICI therapy were more likely to first develop arthritis in the knee, similar to patients with reactive arthritis. Like patients with reactive arthritis, these patients also tended to develop inflammation of the urethra and eye. In addition, patients receiving combination ICI who developed arthritis were more likely to have had signs of inflammation in other organs such as the colon, thyroid, lung and skin. In contrast, patients treated with ICI monotherapy were more likely to first develop arthritis in their small joints and were less likely to have inflammation in other organs. While arthritis symptoms improved after treatment with steroids in most patients, 30% of patients had more severe arthritis that required additional treatment with TNF-inhibitors and/or methotrexate (medications that suppress the immune system). The medications used to treat the patients’ arthritis did not appear to interfere with the ability of the ICI to fight the patient’s cancer. Patients who had a positive cancer response to ICI therapy maintained that response even after the arthritis was treated.
What is the impact of this work?
This is the largest study of patients with inflammatory arthritis induced by ICIs for the treatment of cancer. The finding that different clinical features are observed in patients depending on whether they receive combination ICI or monotherapy suggests a difference in how the arthritis develops in patients treated with different immunotherapy drugs. Understanding this better may help doctors predict which patients will develop which side effects and could lead to better treatments. Though the numbers of patients included in this study are small and further study is needed, it is reassuring to see that patients did not lose their tumor response when their arthritis was treated with medications that suppress the immune system.
This research was suppored by:
- RDRCC / P30
- The Jerome L. Greene Foundation
Link to original research article:
Clinical presentation of immune checkpoint inhibitor-induced inflammatory arthritis differs by immunotherapy regimen. Laura C. Cappelli, MD’Correspondence information about the author MD Laura C. CappelliEmail the author MD Laura C. Cappelli, Julie R. Brahmer, MD, Patrick M. Forde, MBBCh, Dung T. Le, MD, Evan J. Lipson, MD, Jarushka Naidoo, MBBCh, Lei Zheng, MD, PhD, Clifton O. Bingham III, MD1, Ami A. Shah, MD1