Nivolumab and All-trans Retinoic Acid for Pancreatic Cancer

Pancreatic cancer is an aggressive and lethal disease. Even two combination regimens, FOLFIRINOX and albumin-bound paclitaxel in combination with gemcitabine, are superior to gemcitabine alone as the first-line treatments, the prognosis of patients with locally advanced or metastatic pancreatic cancer remains poor, with a median overall survival of 8 to 11 months and an estimated 2-year survival of only 2%. Even more, there is currently no available treatment proven beneficial for patients who fail the second-line therapy with liposomal irinotecan in combination with 5-FU. Immune checkpoint inhibitors targeting PD-1 or PD-L1 represent a popular treatment option for patients with some kinds of cancers, but previous studies in pancreatic cancer have failed. One critical challenge for immunotherapy in pancreatic cancer is to find efficient therapeutic approaches to reverse this "cold" tumor into a "hot" tumor. Our previous basic studies revealed that all-trans retinoic acid repressed pancreatic adenocarcinoma cell growth and colony formation. Set-to-set genetic analysis revealed that genes regulated by all-trans retinoic acid were predominantly involved in immune response including interleukin-6, tumor necrotic factor-α, IFNs signaling, and PD-L1. Furthermore, mice bearing pancreatic cancer treated with combination of anti-PD-1 and all-trans retinoic acid had a significantly longer survival compared to mice treated with anti-PD-1 or all-trans retinoic acid alone. Based on the previous findings, we propose this pilot, compassionate use of combination therapy with all-trans retinoic acid and nivolumab for patients with locally advanced or metastatic pancreatic adenocarcinoma who are refractory to current available treatment. This study will also examine ADAR1 as a novel prognostic and predictive biomarker for pancreatic adenocarcinoma patients. This study will help to delineate the role of ADAR1 as a predictive biomarker for immunotherapy, all-trans retinoic acid as a suppressor of ADAR1, and most importantly, the combination of all-trans retinoic acid and nivolumab as an effective anticancer therapy for patients with pancreatic adenocarcinoma.