This study was designed for patients with advanced bowel cancer after first-line LOHP and 5-FU treatment failure. The control group was treated with second-line CPT-11+C225. The study group used second-line CPT-11 single drug until the third line was CPT-11+C225. treatment. Referring to the previous literature data, the PFS of the second-line treatment of CPT-11+C225 is about 4 months. This study assumes that the total PFS time of C225 can be extended to 7 months after the failure of second-line CPT-11 treatment compared with the direct second-line combination. , set α = 0.05, β = 0.2, the expected enrollment time is 2 years, the follow-up time is 1 year, the 10% sample shedding rate, the total sample size is about 60 cases per group, a total of 120 cases.
The primary endpoint is to evaluate the progression-free survival (PFS).