Abstract
Merkel cell carcinoma (MCC) is a rare neuroendocrine tumor of the skin. Approximately 80% of tumors are Merkel cell polyomavirus (MCPyV) positive and in the rest 20% high rates of UV induced mutations is proven.
MCC is very aggressive malignancy with tendency to metastasize into skin, lymph nodes and distant organs. Recently used chemotherapy had quite high response rate, achieved in some cases almost 60%, but the responses were short term and they did not project into prolongation of overall survival.
Implementation of immunotherapy with inhibitory monoclonal antibodies against PD-1 and PD-L1 receptors led to significant prolongation of progression free survival and overall survival in patients with metastatic MCC (mMCC). The only checkpoint inhibitor, which is currently approved by FDA (Food and Drug Administration) and EMA (European Medicines Agency) for the treatment of mMCC is avelumab.
It is IgG1 monoclonal antibody against PD-L1, highly efficient in the first and further lines of treatment.