A pilot study of immune checkpoint inhibition (tremelimumab and/or MEDI4736) in combination with radiation therapy in patients with unresectable pancreatic cancer

TPS470 Background: Tremelimumab is a fully human monoclonal antibody that binds to CTLA-4 expressed on the surface of activated T lymphocytes and causes inhibition of B7-CTLA-4-mediated downregulation of T-cell activation. MEDI4736 is a human monoclonal antibody directed against PD-L1. Blockage of ligation between PD-L1 and PD1 induces local immune activation and prevents anergy and exhaustion of effector T-cells. Several studies have documented an increase in peripheral antitumor immunity following radiation. This effect is evidently too weak to be clinically relevant, but has the potential to be boosted by immune modulation. The underlying hypothesis of this study is that the effect of immune checkpoint inhibition (accomplished via tremelimumab and/or MEDI4736) treatment can be enhanced by radiation in patients with advanced pancreatic carcinoma. Whilst radiation treatment in pancreas cancer is commonly employed in limited or early stage disease, if radiation can enhance the effect of immune checkpoint inhibition to produce systemic anti-tumor effects the combination could become an effective treatment modality for patients with advanced disease. Methods: Patients with histologically confirmed metastatic pancreatic cancer with primary in-situ (or locally-recurrent) disease are being enrolled to this pilot study. The primary objectives are to determine the safety, tolerability and feasibility of immune checkpoint inhibition [comprising either MEDI4736 alone (Cohort A), Tremelimumab (Cohort B) or combined MEDI4736 and Tremelimumab (Cohort C)] in combination with stereotactic body radiation therapy (SBRT) in patients with unresectable pancreatic cancer. Select eligibility criteria are as follows: at least 1 measurable metastatic lesion by RECIST 1.1 criteria and accessible for biopsy. No prior radiation therapy to the pancreas allowed. There is no limit to the number of prior chemotherapy regimens received; ECOG ≤ 1; Life expectancy of greater than 3 months. Acceptable organ and bone marrow function. No active or prior documented autoimmune or inflammatory disorders. Clinical trial information: NCT02311361.