Histopathologically confirmed patient with an inoperable metastatic colorectal adenocarcinoma.
pMMR or MSS.
CR, PR, or SD (according to RECIST v1.1 criteria) achieved after 12-16 weeks of intensive treatment with a first-line chemotherapy regimen containing irinotecan/fluorouracil or a three-drug chemotherapy regimen containing oxaliplatin/irinotecan/fluorouracil plus bevacizumab.
If previously received neoadjuvant or adjuvant therapy, the time interval between initiation of systemic first-line therapy and the date of last dosing must be at least 6 months.
ECOG 0\~1, patients ≥75 years old need an ECOG score of 0.
Normal bone marrow and organ function: ① Neutrophils (ANC) ≥1.5×10\^9/L, platelets (PLT) ≥75×10\^9/L, hemoglobin (Hb) ≥85g/L, albumin (ALB) ≥30 g/L, white blood cells (WBC) ≥3.0×10\^9/L, and no bleeding tendency; ② AST, ALT and alkaline phosphatase (ALP) were all ≤2.5× upper limit of normal range (ULN), and ≤5×ULN when liver metastases occurred; The total bilirubin level doesn't exceed the upper limit of the agency's normal range; Serum creatinine (Cr) ≤1.5×ULN or creatinine clearance ≥60 ml/min (calculated according to Cockroft-Gault).
Understand the situation of this study, patients and/or legal representatives voluntarily agree to participate in this study and sign informed consent form.
You may not be if
Known or suspected central nervous system metastasis.
Had received surgery or other treatment for tumors other than intensive treatment (including chemotherapy, radiotherapy, research treatment, etc., within 4 weeks prior to enrollment, if the interval between the current treatment was longer than 5 drug half-lives, could be included).
Previous treatment-related toxicity did not return to NCI-CTCAE v5.0 I or below (except for alopecia, peripheral neuropathy).
The use of CYP3A, CYP2C8, and UGT1A1 inhibitors or inducers couldn't be discontinued or were not discontinued within 2 weeks prior to enrollment.
The presence of severe gastrointestinal dysfunction or gastrointestinal perforation, intraperitoneal abscess, and fistula.
Intestinal obstruction, signs and symptoms of intestinal obstruction, or the stent has been previously implanted and the stent has not been removed before the screening period.
Interstitial lung disease.
Tendency of arterial embolism and massive bleeding within 6 months before enrollment (except surgical bleeding).
Patients with fluid accumulation that couldn't reach a stable state but small amount of ascites on imaging without clinical symptoms could be enrolled.
Any serious or uncontrolled systemic disease, including uncontrolled high blood pressure, heart disease, active bleeding, active viral infection, etc.
Have had other malignancies within the past 5 years or currently, except cured cervical carcinoma in situ, uterine carcinoma in situ, and non-melanoma skin cancer.
Patients of childbearing age who refuse to take contraceptives, women who are pregnant or breastfeeding.
The researchers didn't consider it appropriate to participate in this study.
