A Clinical Trial to Test if the Investigational Drug BNT329 is Safe and Potentially Beneficial for People With Advanced Solid Tumors Known to Express the Tumor Marker CA19-9

This study is testing an experimental cancer drug called BNT329 in people with advanced solid tumors that produce a protein called CA19-9 (found in pancreatic cancer, bile duct cancer, bladder cancer, colorectal cancer, ovarian cancer, and esophageal cancer). The goal is to assess safety and early signs of effectiveness. **You may be eligible if...** - You have a confirmed advanced or metastatic tumor that is known to express the CA19-9 protein - Your cancer has progressed on standard treatments and no other standard options are available - Your overall health is reasonably good (ECOG performance status 0–1) - You have a life expectancy of at least 3 months **You may NOT be eligible if...** - Standard treatment options are still available that could help you - You have poor organ function or low blood counts - You have not yet received all available standard treatments for your cancer type Talk to your doctor to see if this trial is right for you.