Pembrolizumab and Pelareorep in Treating Patients With Advanced Pancreatic Cancer

PRIMARY OBJECTIVES: I. To determine the overall response rate (ORR) by Response Evaluation Criteria in Solid Tumors (RECIST) version (v) 1.1 criteria of pembrolizumab in combination with Reovirus Serotype 3 ? Dearing Strain (pelareorep). SECONDARY OBJECTIVES: I. To determine progression free survival by RECIST v 1.1 criteria, as well as 1- year, 2-year and median overall survival with pembrolizumab in combination with pelareorep. II. To determine safety and tolerability of pembrolizumab and pelareorep when administered in combination as determined by National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) v 4.03. III. To determine the effects (immune response) of pembrolizumab and pelareorep when administered in combination as determined by analysis of pre-and post-treatment biopsies and blood-based immune markers. EXPLORATORY OBJECTIVES: I. To measure the overall response rate (ORR) by using Immune-Modified Response Evaluation Criteria in Solid Tumors (iRECIST) criteria, for the combination of pembrolizumab and pelareorep. II. To determine progression free survival by iRECIST criteria as well as 1-year, 2-year and median overall survival with pembrolizumab in combination with pelareorep. OUTLINE: Patients receive pembrolizumab intravenously (IV) over 30 minutes on day 1. Treatment repeats every 21 days for up to 32 courses in the absence of disease progression, unacceptable toxicity, development of an inter-current illness that prevents further administration of treatment, patient decides to withdraw, patients not experiencing clinical benefit in the judgment of the Investigator, or the treating investigator determines that the patient should be taken off treatment for any reason. Patients also receive Pelareorep IV over 60 minutes on days 1, 2, 3, and 8 in course 1 and on days 1 and 8 of subsequent courses. Courses repeat every 21 days for up to 24 months in the absence of disease progression, unacceptable toxicity, development of an inter-current illness that prevents further administration of treatment, patient decides to withdraw, patients not experiencing clinical benefit in the judgment of the Investigator, or the treating investigator determines that the patient should be taken off treatment for any reason. Patients who stop study therapy with stable disease (SD) or better may be eligible for up to 1 year of additional Pelareorep and pembrolizumab therapy if they progress after stopping study treatment. After completion of study treatment, patients are followed up every 3 months for 2 years.