MRI Effects of Pegvorhyaluronidase Alfa (PEGPH20) in Pancreatic Ductal Adenocarcinoma

Inclusion Criteria: 1. Signed Informed Consent Form 2. Capable of giving informed consent. 3. Ability and willingness to comply with the protocol including all scheduled MRI studies and paired tumor biopsies 4. Aged ≥ 18 years. 5. borderline or unresectable pancreatic adenocarcinoma without distant metastatic disease. 6. ECOG PS of 0 or 1 7. Must have adequate organ and hematopoietic function 8. Female and Males must use an approved contraceptive method Exclusion Criteria: 1. Received prior therapy for pancreatic adenocarcinoma 2. History of deep vein thrombosis (DVT) or pulmonary embolism (PE) 3. Contraindication to therapeutic anticoagulation or heparin 4. Intolerance to dexamethasone 5. Contraindication to MRI or unwillingness to undergo all scheduled MRI exams 6. Known or suspected brain metastasis 7. Significant cardiovascular disease such as current New York Heart Associate Class III/IV heart failure, myocardial infarction or stroke within 6 months prior to enrollment 8. A second primary malignancy that, in the judgment of the investigator, may affect the interpretation of results 9. Any illness or condition that in the opinion of the investigator may affect the safety of the subject or the evaluation of any study endpoint 10. Active bacterial or fungal infection requiring IV therapy at the start of protocol treatment 11. Subjects may not receive concomitant anticancer agents or radiation. 12. Female subjects who are pregnant or nursing 13. Pre-existing peripheral neuropathy \> CTCAE Grade 2. 14. Known allergy to hyaluronidase 15. Current use of megestrol acetate (use within 10 days of Day 1) 16. Inability to comply with study and follow-up procedures as judged by the Investigator