In this pilot study, we hypothesized targeting M2-like macrophages, regulated by the colony stimulating factor-1 (CSF1) pathway, would be safe and induce an intratumoral immune response in patients with PDA.<h4>Methods</h4>We tested perioperative combination immunotherapy (CI) with GM-CSF-secreting allogenic pancreatic tumor cell vaccine (GVAX)/cyclophosphamide (CY), pembrolizumab (Pem), and CSF1 receptor blockade (IMC-CS4) in patients with PDA. This evidence concerns the gene CSF1 and Patent ductus arteriosus.