Researchers want to learn if intismeran autogene with pembrolizumab can stop advanced melanoma from growing or spreading. Melanoma is a type of skin cancer. Advanced means the cancer has spread to other parts of the body and cannot be removed with surgery. A standard (or usual) treatment for advanced melanoma is immunotherapy. Immunotherapy is a treatment that helps the immune system fight cancer. Intismeran autogene is a study treatment designed to help a person’s immune system attack their specific cancer. Pembrolizumab is an immunotherapy.

The goal of this study is to learn if people who receive intismeran autogene with pembrolizumab live longer without the cancer growing or spreading than people who receive placebo with pembrolizumab. A placebo looks like the study treatment but has no study treatment in it. Using a placebo helps researchers better understand the effects of a study treatment.