This study is about testing how well the drug Sitagliptin, when combined with two other cancer drugs, Gemcitabine and Albumin-bound Paclitaxel, works for patients with a type of pancreatic cancer called Pancreatic Ductal Adenocarcinoma (PDAC). This type of cancer affects the pancreas, an organ that helps in digestion.

To join, participants must be adults who haven't been treated for advanced or spread-out PDAC before. They need to be in good general health and have certain blood test results within normal limits. They shouldn't have any other cancers, heart problems, or serious infections, and they cannot be pregnant or breastfeeding.

• The study takes place at one location and involves one group of participants receiving the combination treatment.
• Participants must be able to attend regular medical visits for monitoring and tests.
• Participants may face side effects like nausea or tiredness from the treatment.