Poorer survival for patients with inflammatory arthritis treated with immune checkpoint inhibitors for melanoma.

Background: Patients with inflammatory arthritis treated with immune checkpoint inhibitors (ICIs) for melanoma face unique challenges, including disease flares and reduced treatment efficacy. Evidence on the survival impact of pre-existing arthritis in this population remains limited.

Methods: We conducted an observational cohort study using data from two Danish national registries, DANBIO and DAMMED, including patients with melanoma and pre-existing inflammatory arthritis treated with ICIs. Cases were matched with controls without arthritis based on sex, age, melanoma subtype, disease stage, and treatment regimen. Outcomes included overall survival (OS), progression-free survival (PFS)/recurrence-free survival (RFS), changes in rheumatic disease activity, and healthcare utilization.

Results: Seventy-five patients with inflammatory arthritis were identified, initiating 91 ICI treatment courses. Patients with arthritis demonstrated poorer OS (HR 1.4, 95 % CI: 1.04-1.91) and PFS/RFS (HR 1.5, 95 % CI: 1.13-1.94) compared to controls. Subgroup analysis of immunosuppressed patients yielded similar results. Rheumatic disease activity increased post-ICI initiation (mean DAS28 Δ +0.48, p = 0.001), while rheumatologic healthcare utilization decreased.

Conclusions: Patients with inflammatory arthritis have poorer OS and PFS/RFS following ICI therapy for melanoma, partly attributable to baseline immunosuppressive treatment. These findings underscore the need for enhanced multidisciplinary management to optimize outcomes and address the survival gap in this population.