PD-1 mRNA LNP Vaccine for Advanced Primary Hepatocellular Carcinoma.

This study tests a new experimental mRNA vaccine delivered in tiny fat particles (lipid nanoparticles) that blocks a protein called PD-1, which cancer cells use to hide from the immune system. It is being tested in people with advanced liver cancer (hepatocellular carcinoma) that has not responded to other treatments. **You may be eligible if...** - You have been diagnosed with advanced primary liver cancer (hepatocellular carcinoma) - Your cancer has not responded to, or you cannot tolerate, standard treatments - Your liver function and general health meet minimum requirements - You have at least one measurable tumor **You may NOT be eligible if...** - You have liver cancer caused by another primary cancer that spread to the liver - You have severe liver disease or cirrhosis that significantly impairs liver function - You have an active autoimmune disease - You have a serious infection or are immunocompromised Talk to your doctor to see if this trial is right for you.