Treatment outcomes in patients with advanced mucosal melanoma in Spain: results from the real-world GEM1801 study

Patients with mucosal melanoma have lower survival rates than those with cutaneous melanoma. Recent studies have reported lower mucosal melanoma survival rates with the use of immune checkpoint inhibitors (ICIs). This study analyzed ICI treatment outcomes in patients with mucosal melanoma in a real-world context. The objective response rate, progression-free survival (PFS), and overall survival (OS) after first- and second-line ICI treatments were analyzed in a population of patients with advanced mucosal melanoma included in the observational GEM1801 study in Spain. Univariate Cox regression analysis was used to identify prognostic factors. From 1126 patients included between August 2018 and January 2024, 52 (4.6%) patients with mucosal melanoma were selected, with a median age at advanced stage diagnosis of 70 years; 50% were female. Most patients had an Eastern Cooperative Oncology Group performance status of 0 (48%). Tumors were primarily located in the lower gastrointestinal tract (40%) and the nasal cavity (35%). In the metastatic setting, 32 (62%) patients received ICI. At a median follow-up of 13.7 months, patients receiving ICI had a median PFS and OS of 9.4 [95% confidence interval (CI): 6.6-17.0] and 25.9 (95% CI: 21-not reached) months, respectively, for first-line treatment, and 5.1 (95% CI: 1.9-not reached) and 21.0 (95% CI: 11.1-not reached) months for second-line treatment. The clinical benefit of ICI treatment in mucosal melanoma is in accordance with previous clinical trials but is still limited, highlighting the need for new approaches for this patient population.