SON-DP in Participants With Relapsed/Refractory Intolerant to Standard of Care Therapies for Advanced/Metastatic Solid Tumors

This study is testing a new experimental drug called SON-DP in people with advanced solid tumor cancers — particularly liver cancer or gastric (stomach) cancer — that have stopped responding to all available standard treatments. **You may be eligible if...** - You are between 18 and 75 years old - You have a confirmed solid tumor cancer; for the expansion phase, either advanced primary liver cancer or advanced gastric/gastroesophageal junction cancer - Your cancer has at least one measurable tumor on scans - You are in good health (ECOG performance status 0 or 1) - You are willing to have a central venous line (a special IV line) placed - Your expected survival is more than 3 months **You may NOT be eligible if...** - You are not willing to consent or cannot follow study requirements - You have already exhausted all of the listed requirements for tumor type and performance status - You do not have at least one measurable lesion visible on imaging Talk to your doctor to see if this trial is right for you.