Cetuximab and Envafolimab Plus mFOLFOXIRI as First-line Treatment for RAS/BRAF Wild-type, MSS, Unresectable Left-side Metastatic Colorectal Cancer

This is a prospective, open-label, multi-center, randomized controlled phase II trial in which patients with initially unresectable and previously untreated RAS/BRAF wild-type, MSS, left-side mCRC will be randomized to two therapy groups: Experimental arm A: receive induction treatment with cetuximab and envafolimab plus mFOLFOXIRI up to 8 cycles followed by maintenance with cetuximab and envafolimab plus 5-FU/LV until disease progression, unacceptable toxicity or patient's refusal. Standard arm B: receive induction treatment with cetuximab plus mFOLFOX6 up to 8 cycles followed by maintenance with cetuximab plus 5-FU/LV until disease progression, unacceptable toxicity or patient's refusal. The second- and subsequent lines of treatment will be at investigators' choice.