Pembrolizumab In Central Nervous System Metastases

This research study is a Phase II clinical trial. Phase II clinical trials test the safety and effectiveness of an investigational intervention to learn whether the intervention works in treating a specific disease. "Investigational" means that the intervention is being studied. Pembrolizumab may help the immune system fight cancer. The FDA (the U.S. Food and Drug Administration) has approved pembrolizumab FDA for some diseases that are being treated on this study, but not for central nervous system metastases. Researchers hope to study the effects of pembrolizumab. Many cancers use specific pathways (such as PD-1/PD-L1 and CTLA-4) to evade the body's immune system. Pembrolizumab works by blocking the PD-1/PD-L1 pathways and thus releasing the brakes on the immune system so it can stop or slow cancer. Researchers hope to study the effects of pembrolizumab in cancer that has metastasized to the brain. These drugs work by stimulating the immune system to fight cancer.