Immune-related adverse events of dendritic cell vaccination correlate with immunologic and clinical outcome in stage III and IV melanoma patients

The purpose of this study was to determine the toxicity profile of dendritic cell (DC) vaccination in stage III and IV melanoma patients, and to evaluate whether there is a correlation between side effects and immunologic and clinical outcome. This is a retrospective analysis of 82 stage III and 137 stage IV melanoma patients, vaccinated with monocyte-derived or naturally circulating autologous DCs loaded with tumor-associated antigens gp100 and tyrosinase. Median follow-up time was 54.3 months in stage III patients and 12.9 months in stage IV patients. Treatment-related adverse events occurred in 84% of patients; grade 3 toxicity was present in 3% of patients. Most common adverse events were flulike symptoms (67%) and injection site reactions (50%), and both correlated with the presence of tetramer-positive CD8⁺ T cells (both P<0.001). In stage III melanoma patients experiencing flulike symptoms, median overall survival (OS) was not reached versus 32.3 months in patients without flu-like symptoms (P=0.009); median OS in patients with an injection site reaction was not reached versus 53.7 months in patients without an injection site reaction (P<0.05). In stage IV melanoma patients (primary uveal and mucosal melanomas excluded), median OS in patients with or without flu-like symptoms was 13.1 versus 8.9 months, respectively (P=0.03); median OS in patients with an injection site reaction was 15.7 months versus 9.8 months in patients without an injection site reaction (P=0.003). In conclusion, DC vaccination is safe and tolerable and the occurrence of the immune-related side effects, such as flu-like symptoms and injection site reactions, correlates with immunologic and clinical outcome.