Inclusion Criteria:

          -  Patient has signed informed consent and is willing to comply with the protocol

          -  Cytologic or biopsy confirmed adenocarcinoma of the pancreas

          -  TNM stage: Tx, T1-4, N0-1 or Nx, M0

          -  Potentially resectable pancreatic cancer defined as no extra-pancreatic disease, no
             evidence of tumor extension to the celiac axis, common hepatic artery and superior
             mesenteric artery, and no evidence of deformity of the superior mesenteric vein or
             superior mesenteric portal vein confluence

          -  No evidence of distant metastases either prior to or after induction chemotherapy

          -  Able to comply with instructions required for radiation therapy

          -  Age 18 years or older

          -  Completion of 2-6 months of standard induction chemotherapy (mFOLFIRINOX, gemcitabine
             and nab-paclitaxel or other)

          -  Eastern Cooperative Oncology Group Score 0, 1 or 2

          -  Adequate haematologic function (absolute neutrophil count ≥1500mm3; haemoglobin ≥8.0
             g/dL; platelet count ≥50000mm3)

          -  Adequate renal and liver function (creatinine ≤ 1.5 x upper limit of normal; total
             bilirubin ≤ 1.5 x upper limit of normal; aspartate aminotransferase and alanine
             aminotransferase ≤ 2.5 x upper limit of normal; alkaline phosphatase ≤ 2.5 x upper
             limit of normal

        Exclusion Criteria:

          -  Prior radiation therapy to the abdomen that would overlap with the treatment field

          -  Prior surgical resection of pancreatic tumor

          -  Receiving any approved or investigational anti-cancer agent other than those provided
             for in this study

          -  Uncontrolled or active gastric or duodenal ulcer disease within 30 days of dosing

          -  Residual or ongoing ≥Grade 3 toxicity from chemotherapy

          -  Contraindication to IV contrast that can't be managed with pre-medication

          -  Concurrent participation in another interventional clinical trial or use of another
             investigational agent within 30 days of consent (concurrent non-interventional trials
             are eligible)

          -  Uncontrolled intercurrent illness including but not limited to, symptomatic congestive
             heart failure, unstable angina pectoris, renal failure, cardiac arrhythmia, stroke, or
             psychiatric illness that would limit compliance with treatment

          -  Second primary malignancy within the last 5 years, unless treated definitively and/or
             low risk in the judgement of the treating investigator

          -  Known history of HIV or active hepatitis B/C (patients who have been vaccinated for
             hepatitis B and do not have history of infection are eligible)

          -  Known intolerance or hypersensitivity to study drug

          -  Subjects who are allergic to amoxicillin/clavulanic acid, erythromycin and imipenem

          -  Female subjects who are breastfeeding

          -  Women of child-bearing potential who are unwilling or unable to use an acceptable
             method of birth control for the entire study and for 30 days after last dose of
             MRx0518. A negative pregnancy test must be obtained within 14 days prior to start of
             treatment

          -  Male subjects who are unwilling or unable to use an acceptable method of birth control
             for the entire study period and for 30 days after last dose of MRx0518

          -  Serious infection requiring systemic therapy

          -  Use of systemic antibiotics within 2 weeks of start of study treatment

          -  Has a known inability for intake of oral capsules