DOVIPA, a Study Evaluating Efficacy and Safety of DOstarlimab and VItamin D3 With mFOLFIRINOX in PAncreatic Cancer

The goal of this clinical trial is to estimate the antitumor response of mFOLFIRINOX + Dostarlimab + oral HD vitamin D3 in patients with non-pretreated histologically confirmed metastatic Stage IV adenocarcinoma of the pancreas. The patients must have an Eastern Cooperative Oncology Group (ECOG)-Performance Status (PS) 0 or 1 and adequate organ functions. The main objective of the study will be assessed by estimating Objective response rate (ORR) according to Response Evaluation Criteria version 1.1 (RECIST 1.1) in patients with pancreatic adenocarcinoma and measurable disease. The Secondary objectives are : * To assess the safety and tolerability of mFOLFIRINOX + Dostarlimab + HD Vitamin D according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 by evaluating the Median Progression Free Survival (mPFS) in months, the Median Overall Survival (mOS) in months, the Median Duration of Response (mDOR) in months and Clinical benefit rate according to RECIST 1.1 (CBR) * To further evaluate the antitumor efficacy of mFOLFIRINOX + Dostarlimab + oral HD Vitamin D by evaluating the type, frequency, and severity of treatment-emergent adverse events (TEAEs); adverse events of special interest (AESIs); safety laboratory findings There are also exploratory objectives to better understand the pancreatic adenocarcinoma. Participants will be cared for in the digestive oncology department. A selection review will be carried out to check compliance with the study eligibility criteria. Patients included in the study will be treated with 4 cycles of induction therapy. Each cycle lasts 6weeks and includes chemotherapy such as mFolfirinox D1,D15 and D29, combined with dostarlimab 500 mg every 3 weeks and daily oral vitamin D3. At the end of the induction treatment period, maintenance treatment will be instituted with LV5FU chemotherapy combined with dostarlimab 1000 mg every 6 weeks and daily oral vitamine D3. Treatment will be maintained until progression or unacceptable toxicity. Throughout this period, patients will be monitored for their safety. Imaging examinations will also be carried out to monitor the progression of tumour disease.