Patients with rheumatologic disease and cancer may not experience as high a rate of immune-related adverse events (IRAEs) when treated with immune checkpoint inhibitors (ICIs) compared with the general population as previously thought, according to a study published in Arthritis & Rheumatology.

ICI use in the treatment of cancer is accompanied with risk for IRAEs, but the incidence in which IRAEs may occur among patients with comorbid rheumatologic disease has not been extensively studied due to fear of inducing disease flares.

For this retrospective study, researchers identified 16 patients with rheumatologic disease (eg, rheumatoid arthritis, polymyalgia rheumatica) who later developed cancer and were treated with immune checkpoint inhibitors such as ipilimumab, nivolumab, or pembrolizumab. Fifteen patients had advanced disease and had received prior chemotherapy. There were no significant differences in time from cancer diagnosis to receipt of immunotherapy, duration of immunotherapy, or baseline characteristics.

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Of the 16 study patients, 6 (38%) experienced grade 2 to 4 IRAEs, including colitis, polyarthritis, pneumonitis, and hypophysitis. Only 1 patient exhibited a flare of their rheumatologic disease.

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Most IRAEs occurred on the fourth cycle of treatment or earlier, and every IRAE was managed successfully with the discontinuation of ICI therapy or glucocorticoid administration.

Interestingly, patients who experienced IRAEs survived longer than did those who did not (17 months vs 1.4 months; P =.003). A possible explanation is that patients with healthy immune responses are more likely to respond to immunotherapy and thereby experience IRAEs, plus combination ICIs not only lead to improved overall survival but also greater incidence of IRAEs. The researchers theorized that there may be an association between IRAE incidence and treatment efficacy.

The researchers concluded that despite the findings, “larger, prospective studies will be necessary to validate the findings and establish evidence-based guidelines for appropriate identification and rating of the rheumatologic IRAEs as well as their treatment, such that patients can continue to receive potentially life-saving cancer treatments.”


Richter MD, Pinkston O, Kittschade LA, et al. Cancer immunotherapy in patients with preexisting rheumatologic disease: the Mayo Clinic experience [published online January 24, 2018]. Arth Rheum. doi: 10.1002/art40397