Pancreatic cancer is the third leading cause of
cancer-related deaths in the United States with a 5-year survival less than 5%. Resistance to standard
therapy and limited response to
immune checkpoint blockade due to the immunosuppressive and stroma-rich microenvironment remain major challenges in the treatment of
pancreatic cancer. A key cellular program involved in
therapy resistance is epithelial plasticity, which is also associated with invasion,
metastasis, and evasion of immune surveillance. The
receptor tyrosine kinase AXL is a key driver of
tumor cell epithelial plasticity. High expression and activity of AXL is associated with poor prognosis,
metastasis, and
therapy resistance in multiple types of
cancer including pancreatic. Here, we show that an AXL inhibitor (TP-0903), has antitumor and
therapy sensitizing effects in preclinical models of pancreatic ductal
adenocarcinoma (PDA). We demonstrate that
TP-0903 as a single agent or in combination with
gemcitabine and/or anti-
programmed cell death protein 1 (PD1) antibody has anti-metastatic and anti-
tumor effects in PDA
tumor bearing mice, leading to increased survival. In addition, gene expression analysis of
tumors demonstrated upregulation of pro-inflammatory and immune activation genes in
tumors from TP-0903-treated animals compared with the vehicle, indicating pharmacologic inhibition of AXL activation leads to an immunostimulatory microenvironment. This effect was augmented when
TP-0903 was combined with
gemcitabine and anti-PD1 antibody. These results provide clear rationale for evaluating
TP-0903 in the treatment of
pancreatic cancer.