Intralesional and systemic immunotherapy for metastatic melanoma

Immunotherapy has revolutionized the treatment of metastatic melanoma and dramatically improved patient outcomes. Ipilimumab, an inhibitor of cytotoxic T-lymphocyte antigen-4 (CTLA-4), was the first immunotherapeutic agent to demonstrate improved survival in advanced melanoma. More recently, other immune checkpoint inhibitors, including the programmed death-1 (PD-1) inhibitors pembrolizumab and nivolumab, have demonstrated efficacy in locally advanced unresectable and metastatic melanoma. In addition to systemically delivered immunotherapies, intralesional therapies such as talimogene laherparepvec (TVEC) play an important role in the treatment of locoregionally advanced and metastatic melanoma. Areas covered: This review provides an overview of the mechanisms behind immune checkpoint inhibitors. Clinical evidence of their efficacy is presented and discussion of new patterns of response and associated immune related adverse events associated with immunotherapy are provided. Expert opinion: Treatment options for locally advanced and metastatic melanoma are expanding with new developments in immunotherapy and immune checkpoint inhibitors. The utility of these novel therapies in the adjuvant setting is currently being explored. The ideal treatment of metastatic melanoma continues to be multimodal, combining systemic treatments, intralesional and regional therapies, surgery and radiotherapy to achieve optimal outcomes.