Immune Checkpoint Inhibitor Data in Metastatic Melanoma with Pre-Existing Autoimmune Disease: A Real World Experience

Patients with pre-existing autoimmune disease (AID) are underrepresented in trials of immune checkpoint inhibitors (ICIs). We retrospectively compared 41 patients with stage IV melanoma and pre-existing AID with 162 contemporaneous controls without AID who received ICI treatment between November 2016 and April 2023. In the AID and control cohorts, respectively, the objective response rates were 46.3% and 32.7%, and the disease control rates were 80.5% and 51.2%. Treatment interruption attributed to worsening of the baseline AID was recorded in 11/41 patients, while 13/41 interrupted treatment because of toxicity distinct from the baseline AID. The full cohort contributed 114 progression-free survival (PFS) events and 92 deaths. In models adjusted for age, sex, ICI regimen and M category, AID was associated with PFS (adjusted hazard ratio [HR] 0.48, 95% confidence interval [CI] 0.24-0.99; p = 0.046), whereas the association with overall survival (OS) was not statistically significant (adjusted HR 0.63, 95% CI 0.29-1.34; p = 0.232). These findings support the feasibility of ICI therapy in carefully selected patients with clinically stable AID, while the observational design and residual confounding require cautious interpretation of comparative outcomes.