Utility of ctDNA in Early Switch of First-line mFOLFIRINOX in Metastatic Pancreatic Ductal Adenocarcinoma

The purpose of this study is to understand whether a blood-based test called circulating tumor DNA (ctDNA) can detect whether participants are having a desired tumor shrinkage or an undesired lack of tumor shrinkage, and to study whether these levels of ctDNA can be used to make treatment decisions faster than the current standard approach, which is to wait 8 weeks after starting chemotherapy to obtain participant first imaging scans since starting chemotherapy.