Fruquintinib combination with sintilimab in refractory metastatic colorectal cancer patients in China.

4028 Background: Fruquintinib, a vascular endothelial growth factor receptor (VEGFR) inhibitor, is a new anti-cancer targeting drug independently developed in China for refractory metastatic colorectal cancer (mCRC). Because Regorafenib combined with nivolumab has a promising future in patients with refractory mCRC, we aim to evaluate the efficiency of combination of Fruquintinib with Sintilimab (a highly selective, fully human monoclonal antibody PD-1 mAb) in these patients. Methods: Fifty-two patients with refractory mCRC were given fruquintinib (3mg orally, once daily for 3 weeks, followed by 1 weeks off in 4 weeks cycles) and sintilimab (200mg intravenously, once every 3 weeks). Before treatment, peripheral blood samples were collected and next-generation sequencing was performed to detect the gene profile of patients. Results: The ORR was 15.38% (8/52), DCR was 57.6% (30/52), and mPFS was 108 days. The patients was divided into two groups according to their PFS: PFS ≥ 90 days and PFS <90 days. PFS was significantly worse in patients with the following mutations: AMER1 ( p=0.0073), DNMT3A ( p=0.0075), ETV5 ( p=0.012), EWSR1 ( p=0.016), FANCA ( p=0.019), IKBKE ( p=0.0073), NOTCH1 ( p=0.015), STAG2 ( p=0.012) and TCF7L2 ( p=0.0073). It was also significantly worse in the patients had the abnormalities of complexity and coagulation cascades ( p = 0.026) and pancreatic cancer pathway ( p = 0.0098). Conclusions: Fruquintinib combined with Sintilimab seemed not resulted in a significant increase in ORR, DCR and OS in refractory mCRC. Certain mutational genes and abnormal pathway caused by some frameshift mutations may affect the efficacy. It is suggested that targeting these mutational genes and signaling pathway may be helpful to improve the efficacy of Fruquintinib combination with Sintilimab.