Prospectively Defining Metastatic Pancreatic Ductal Adenocarcinoma Subtypes by Comprehensive Genomic Analysis

Inclusion Criteria: * Histological and/or radiological diagnosis of metastatic PDAC. Patients without a histological diagnosis of PDAC must undergo confirmatory tumour biopsy prior to treatment start date. * Planned for first-line systemic therapy with FOLFIRINOX or GP, either in routine care or in combination with an investigational agent(s) within a clinical trial. * Age ≥ 18 years * Eastern Cooperative Oncology Group (ECOG) performance status 0-1 * Adequate organ function * Life expectancy of \> 90 days as judged by the investigator * Ability to give informed consent * Measurable disease by RECIST 1.1 * Presence of a tumour lesion amenable to core needle biopsy as judged by a staff interventional radiologist. A minimum of 3 tumour cores must be safely obtainable under CT or US guidance. * Fit enough to safely undergo a tumour biopsy as judged by the investigator * Ability to lie supine for \> 60 minutes Patients in the archival cohort must also fulfil the following criteria: * Archival tumour sample available (either a previous tumour diagnostic biopsy or resection specimen) Exclusion Criteria: * Absence of distant or lymph node metastases. Patients with borderline resectable or locally advanced PDAC are not eligible. * Received prior systemic therapy (chemotherapy or any other anti-cancer agent) in the advanced setting. Patients who received adjuvant chemotherapy after surgical resection of early stage disease are eligible. * Currently receiving anti-cancer therapy (chemotherapy or any other anti-cancer agent) * Not fit for combination chemotherapy as judged by the investigator * Presence of brain metastases * Female patients with positive pregnancy test * Patients who are not safe to include in the study as judged by the investigator for any medical or non-medical reason * Unable to comply with study assessments and follow-up