Background: Pancreatic cancer is the third most common cause of cancer death. Surgery offers the best survival rates however only a minority of patients are eligible. Approximately 15-20% of patients are deemed unresectable due to vascular involvement LA. Conversion of unresectable tumors, due to vascular involvement to resectable, is an unmet clinical need. Methods: A novel approach was developed to destroy the tumor encasing the artery combining padeliporfin, a photosensitive drug, locally activated by laser light illumination. The effectiveness of the strategy was confirmed in an orthotopic mouse model. A proof-of-concept study using 12 non-tumor pigs demonstrated an acceptable safety profile. A phase I dose escalation trial (NCT5918783) will be performed to evaluate the safety and maximal tolerated dose (MTD) of laser light dose of padeliporfin VTP. VTP will be delivered through an endovascular fiber integrated in a standard angioplasty balloon. The balloon will be advanced under fluoroscopy to the encased vascular segment of the superior mesenteric artery (SMA) and inflated. Following IV administration of padeliporfin, it will be activated by the laser light. Part A will be a classic 3+3 dose-escalation design to determine the MTD of laser light. The identified MTD will be applied in the Part B for preliminary efficacy evaluation. The primary objectives are to determine safety and MTD and/or recommended phase 2 laser light dose of VTP treatment. Secondary objectives are: rate of surgical conversion; evaluation of the pattern of disease progression (local regional and/or metastatic disease) after VTP based on CT. Standard of care surgery can be performed after 14 days post VTP. Key inclusion criteria: patients with histologically/cytologically confirmed stage III unresectable LA-PDAC in the head/uncinate process of the pancreas, with SMA solid tumor contact ˃180° with measurable disease per RECIST 1.1 and ECOG 0-1. Key exclusion criteria: metastatic disease, other malignancy, photosensitive skin diseases or porphyria, concurrent investigational therapy within past 30 days, medically uncontrolled moderate or severe ascites, previous radiation to pancreas, SMA variants. Recruitment begins in April 2024. Conversion of unresectable locally advanced pancreatic cancer to surgery is a critical unmet need. This phase I trial explores a novel approach to treat the tumor encasement enabling surgery. Clinical trial information: NCT5918783.