Evaluation of Polychemotherapy With XELOXIRI-3 in Elderly or Frail Patients With Advanced Pancreatic Adenocarcinoma

Main Inclusion Criteria : * Histologically proven pancreatic ductal adenocarcinoma * Locally Advanced or metastatic disease * Measurable disease according to RECIST v1.1 criteria * Age ≥ 75 years; OR age between 65 and 75 years AND with at least one frailty contraindication to the administration of chemotherapy with FOLFIRINOX: * Eastern Cooperative Oncology Group Performance status (ECOG-PS) 2 * Total serum bilirubin \> 1.5 ULN (biliary drainage allowed) * Clinico-biological frailty criteria: * weight loss \> 10% in 6 months or \> 5% in 1 month * or body mass index (BMI) ≤ 21 * or serum albumin \< 30 g/L * or ADL (Activities of Daily Living) score \< 6 * Eligible for gemcitabine as first-line chemotherapy * Registration in a national health care system * Written informed consent obtained from the patient prior to performing any protocol-related procedures Main Exclusion Criteria: * Age \< 65 years * Localized non-metastatic cancer * ECOG-PS 3-4 * Previous treatment For advanced stage (locally advanced or metastatic): chemotherapy, radiochemotherapy; For localized stage: FOLFIRINOX chemotherapy (neoadjuvant or adjuvant); adjuvant chemotherapy with gemcitabine before relapse is permitted (provide it has been administered more than 6 months before) * Uncontrolled intercurrent cardiovascular disease * Known or suspected allergy or hypersensitivity to any of the study drugs (capecitabine, oxaliplatin, irinotecan, gemcitabine) * Bowel obstruction or sub-obstruction or impossible oral treatment * Prior peripheral neuropathy of grade ≥ 2 * Known complete dihydropyrimidine dehydrogenase (DPD) or UDP-glycosyltransferase 1 polypeptide A1 (UGT1A1) deficiency * Inadequate hematological, hepatic, and renal functions * Psychiatric illness/social situations that would limit compliance with study requirement, substantially increase risk of incurring AEs (Adverse Events) or compromise the ability of the patient to give written informed consent * Tutelage or guardianship * Diagnosis of any second malignancy within the last 2 years, except for adequately treated basal cell or squamous cell skin cancer, or in situ carcinoma of the cervix uteri * Current participation in another clinical trial using therapeutic experimental agents