CAPEOX and bevacizumab combined with or without sintilimab (recombinant fully human anti-programmed death receptor 1 monoclonal antibody) in the first-line conversion therapy for initial unresectable microsatellite stable colorectal cancer liver metastases with RAS mutation or right-sided primary: A randomized, open-label, multi-center phase II study

Interventions: Group A:Bevacizumab 7.5mg/kg, administered on the first day, intravenous injection; oxaliplatin 130mg/m^2 administered on the first day, intravenous injection; capecitabine 1g/m^2 twice a day, orally, continuously 14 days, 1 week off, 3 weeks for a cycle;Group B:Bevacizumab 7.5mg/kg, administered on the first day, intravenous injection; oxaliplatin 130mg/m^2 administered on the first day, intravenous injection; capecitabine 1g/m^2 twice a day, orally, continuously 14 days, 1 week off; sintilimab 200mg, administered on the first day, intravenous injection,3 weeks for a cycle.
Primary outcome(s): objective response rate
Study Design: Parallel