Dendritic cell vaccination in melanoma patients: From promising results to future perspectives

Dendritic cells (DCs) play an important role in the induction of antitumor immunity. Therefore, they are used as anti-cancer vaccines in clinical studies in various types of cancer. DC vaccines are generally well tolerated and able to induce antigen-specific T cell responses in melanoma patients. After DC vaccinations, functional tumor-specific T cells are more frequently detected in stage III melanoma patients, as compared to patients with advanced melanoma, indicating that the tumor load influences immunological responses. Furthermore, long-lasting clinical responses were rarely seen in metastatic melanoma patients after DC vaccination. Since more potent treatment options are available, e.g. immune checkpoint inhibitors and targeted therapy, DC vaccination as monotherapy may not be preferred in the treatment of advanced melanoma. However, encouraging results of DC vaccines combined with ipilimumab have been reported in advanced melanoma patients with an objective response rate of 38%. DC vaccines show promising clinical results in stage III patients, although clinical efficacy still needs to be proven in a phase 3 trial. The clinical and immunological results of DC vaccination in stage III melanoma patients might be further improved by using naturally circulating DCs (myeloid DCs and plasmacytoid DCs) and neoantigens to load DCs.