Combination Therapy in Patients With Localized Pancreatic Ductal Adenocarcinoma

The overall objective of this study is to combine standard radiation therapy with drugs that stimulate the body's immune system against cancer cells (by targeting the protein programmed cell death (PD-1), while adding drugs which also target the pathway that the tumor uses to evade the immune system (the CD73 and A2a/b pathways).The main goal of this study is to find out if study treatment with zimberelimab (an antibody which binds the protein PD-1) and stereotactic body radiation therapy (SBRT) alone or in combination with quemliclustat (a drug which blocks CD73), with or without etrumadenant (a drug which blocks the A2a/b) given before surgery is safe and if it can further increase the immune response against the tumor. The study is divided into two parts (Stage 1 and Stage 2). In Stage 1 participants will undergo 5 days of SBRT and receive zimberelimab, quemliclustat and etrumadenant (Arm A) for 7 weeks before surgery. If this combination is considered safe, the study will proceed to Stage 2. In Stage 2, participants will be randomized into one of three different treatment arms (B - D). All participants will undergo SBRT and will receive either Zimberelimab alone (Arm B), a combination of zimberelimab with quemliclustat (Arm C), or will receive combination of zimberelimab, quemliclustat and etrumadenant (Arm D) for 7 weeks prior to surgery.