Immunotherapy in lung cancer
Survival rates for metastatic lung cancer including non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) are poor with 5-year survival of less than 5%. The use of molecular targeted therapies has improved median overall survival (OS) in a limited group of NSCLC patients whose tumors harbor specific genetic alterations. However for a large group of NSCLC and SCLC molecular alterations are not available to lead to direct targeted therapies. Recent favorable results of newer trials of therapeutic vaccines and checkpoint inhibitors have proven against the common belief that lung cancer is nonimmunogenic. In particular, the checkpoint inhibitors targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and the programmed death-1 (PD-1) pathway have shown durable clinical responses with manageable toxicity. Several phase II and III clinical trials testing the association of different schedule of chemotherapy and immunotherapy or immunotherapy alone are ongoing in lung cancer and important results are expected in the near future. However, more studies are needed to understand the optimal combination of immunotherapeutic agents with chemotherapy and radiation therapy for the treatment of NSCLC and SCLC.