Abstract
PURPOSE: To investigate real-world treatment patterns, incidence of immune-related adverse events (irAE), and impact of irAEs on outcomes in MBM. METHODS: We performed a retrospective study on MBM patients treated with immunotherapy in 2011-2022. RESULTS: Of the 1979 patients treated with immunotherapy, 453 had melanoma and 138 developed MBM. Median time from melanoma diagnosis to CNS metastasis was 37.8 months and median CNS PFS was 11.1 months. Higher burden of MBMs (6-10 or 11+) was associated with worse CNS PFS compared with low MBM burden (1-5 lesions) (HR = 1.89, 95% CI [1.10-3.25]; p = 0.022), (HR = 1.92, 95% CI [1.02-3.63]; p = 0.044). Synchronous MBM (within 30 days of stage IV diagnosis) was associated with improved CNS PFS (HR = 0.65, 95% CI [0.43-0.99]; p = 0.046). Median OS was 22.3 months from development of MBM and 35.0 months from date of first-line therapy for advanced melanoma. All patients received ICI and most (60.1%) developed any grade irAE. Patients who received combination ICI had higher rates of irAE than patients who received single-agent ICI (χ(2) = 16.31, p < 0.001). Development of irAE was associated with improved median OS (45.0 months vs 21.7 months, HR = 0.50, 95% CI [0.30-0.83]; p = 0.008). CONCLUSION: Incidence of irAE was associated with improved survival and trended toward improved CNS PFS.