A Study to Compare QLS31905 and Chemotherapy With Placebo and Chemotherapy in Participants With Pancreatic Cancer

This study is testing a new drug called QLS31905 combined with standard chemotherapy in people with pancreatic cancer that cannot be surgically removed or has spread to other parts of the body. The goal is to see if adding QLS31905 improves outcomes compared to chemotherapy alone. **You may be eligible if...** - You have been confirmed to have pancreatic cancer through a tissue or cell sample - Your cancer has not been treated with prior systemic (body-wide) therapy - You have at least one measurable tumor and are well enough to participate (ECOG 0–1) - Your heart, liver, and kidneys are functioning adequately - You are expected to survive at least 3 months **You may NOT be eligible if...** - You have had another cancer in the past 5 years - You have had major surgery in the past 28 days or need surgery during the study - You have cancer spread to the brain - You have hepatitis B, hepatitis C, syphilis, or HIV Talk to your doctor to see if this trial is right for you.