Background/Purpose: Immune checkpoint inhibitors (ICIs) are effective therapies in the treatment of many cancers, but their use has been linked with immune-related adverse events (irAEs). As use of ICIs becomes more widespread, more patients are developing irAEs including rheumatologic manifestations. Thus, it is important that clinicians monitor for irAEs and identify patients who may be at increased risk for developing them. We sought to describe the prevalence and presentation of irAEs, both in general and specifically rheumatologic, in order to better characterize their clinical manifestations and recognize potential predisposing risk factors. We hypothesized that patients with preexisting rheumatologic disease would experience irAEs at an increased rate compared to those without preexisting conditions.

Methods: We performed an IRB approved retrospective review using an EMR database of patients treated with ICIs at our institution from January 2011 to April 2017. We reviewed charts to assess for the presence of preexisting rheumatologic disease as well as the development of irAEs during ICI treatment. In patients who experienced an irAE, we determined whether they required additional work up, glucocorticoid treatment, hospitalization, or cessation of ICI therapy. To see if there was an association between preexisting rheumatologic disease and developing irAEs, we did comparative analysis using the Fisher exact test. 

Results: Of 420 patients treated with ICIs, 4.8% (n=20) experienced rheumatologic irAEs. As a result, 4 were referred for rheumatology consultation, 7 were treated with glucocorticoids, 3 had to delay or stop ICIs, and 0 required hospitalization. Preexisting rheumatologic disease was present in 4.8% (n=20). In this subgroup, 65% (n=13) developed any irAE compared to 43% (n=172) of those without preexisting rheumatologic disease (p=0.065). 15% (n=3) developed a rheumatologic irAE compared to 4.25% (n=17) of those without preexisting rheumatologic disease (p=0.063).

Conclusion: We did not detect a statistically significant difference in the rates of irAEs in patients with preexisting rheumatologic disease; however, this study was limited by its retrospective design and relatively small sample size. Given that p-values neared significance, it is possible that this study was underpowered to detect a true relationship and thus additional, larger studies would be beneficial to further investigate. Overall, the majority of rheumatologic irAEs did not require treatment or lead to cessation of ICI therapy. This suggests that even if there is found to be a significant relationship between preexisting rheumatologic disease and the development of irAEs, this risk factor should not preclude this population from receiving ICI therapy but would require careful monitoring and collaboration between these patients’ oncologists and rheumatologists.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/complications-of-immune-checkpoint-inhibitor-therapy-in-patients-with-and-without-pre-existing-rheumatologic-disease/