Inflammatory arthritis persists post immune checkpoint inhibitor therapy
medwireNews: Immune checkpoint inhibitor (ICI)-induced inflammatory arthritis (IA) among patients with cancer may need long-term management by rheumatologists after cessation of treatment, but does not appear to affect cancer outcomes, say researchers.
The prospective study included 60 patients (median age 58.5 years, 53% women) with a rheumatologist-confirmed diagnosis of IA associated with ICI use in the treatment of melanoma (35.0%), non-small-cell lung cancer (23.3%), and gastrointestinal (11.7%), genitourinary (6.7%), gynecologic (5.0%), and other (18.3%) cancers.
The majority (70%) of patients were treated with ICI monotherapy for their cancers and three-quarters needed immunomodulatory agents to treat their IA.
As reported in the Annals of the Rheumatic Diseases, 70.6% of 51 patients still had active IA 3 months after stopping ICI treatment and 48.8% of 41 patients had active IA at 6 months. Furthermore, 70.0% of the patients with persistent IA at 6 months continued to have active disease at further follow-up visits.
Kaplan–Meier curves showed that individuals treated with combination immunotherapy and those with two or more immune-related adverse events (irAEs) were more likely to have persistent IA than those treated with monotherapy or those with fewer irAEs, respectively.
And multivariate analysis showed that each additional month of ICI treatment was associated with a significant 18% lower likelihood that IA would improve after treatment cessation, while the likelihood was a significant 94% lower with combination ICI therapy compared with monotherapy.
The researchers also observed a nonsignificant trend towards a higher rate of persistent IA among patients with a complete or partial response to ICI therapy relative to those with stable or progressive disease, which they say “could reflect ongoing activation of the immune system that portends better antitumour immunity.”
In addition, Laura Cappelli (Johns Hopkins School of Medicine, Baltimore, Maryland, USA) and team found that the use of immunomodulatory agents did not appear to affect tumor response. Disease progression rates were a comparable 16.7% among 24 patients who received disease-modifying antirheumatic drugs and 22.2% among 36 patients who did not.
Cappelli and co-authors conclude that their study “provides insight into which individuals are at highest risk for developing persistent IA, thus warranting close monitoring for joint-related symptoms, early referral to and close follow-up by rheumatology and potentially more aggressive immunosuppressive therapy.”
They add: “Further prospective cohort studies are needed to determine which irAEs besides IA are likely to persist or present after ICI cessation.”
By Laura Cowen
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