mFOLFOX6 Combined With Dalpiciclib in Patients With Metastatic Colorectal Cancer

Inclusion Criteria:

* Subjects voluntarily sign informed consent
* Age: from 18 to 70 years old
* Definite histological evidence of colorectal adenocarcinoma
* ECOG 0-1
* Advanced or metastatic colorectal cancer (AJCC/UICC stage IV) is confirmed by enhanced CT of the chest, abdomen and pelvis, with evaluable lesions
* Tumor progression or intolerable toxicity after previous standard treatment; Tumor progression during adjuvant therapy or within 6 months after completion of adjuvant therapy was considered as first-line treatment (Standard treatment must include all of the following drugs: fluorouracil, irinotecan, and oxaliplatin; With or without anti-VEGF monoclonal antibody (bevacizumab); Anti-EGFR treatment(cetuximab or panitumumab) in left colorectal RAS (KRAS/NRAS) wild-type subjects)
* The bone marrow, liver and kidney function satisfies the following conditions within 7 days before treatment (including day 7):

Hemoglobin ≥90g/L, neutrophil count ≥1.5×109/L, platelet count ≥75×109/L; aspartate aminotransferase (AST) ≤ 2 upper limit of normal (ULN), glutaminate alanine transaminase (ALT) ≤ 3 ULN, total bilirubin ≤ 1.5 ULN, serum creatinine ≤ 1.5 ULN

* Peripheral neurological lesions recover (≤ grade 1) before enrollment
* Subjects should not participate in other clinical trials during the study period
* Willing and able to comply with research procedures and follow-up plan

Exclusion Criteria:

* Complicated with obstruction, active bleeding or perforation and requiring emergency surgery or stent placement
* Existing or coexisting other active malignancies
* Previously CDK inhibitors treatment
* Major surgery or severe trauma such as laparotomy, thoracotomy or laparoscopic organ removal within the previous 4 weeks
* Active coronary artery disease, severe/unstable angina or newly diagnosed angina or myocardial infarction in the past 12 months
* Thrombotic or embolic events occurred within the previous 6 months, such as cerebrovascular accident (including transient ischemic attack), pulmonary embolism or deep vein thrombosis
* New York Heart Association (NYHA) Class II or higher Congestive heart failure
* Presence of clinically symptomatic third space effusion (eg, massive pleural or ascites) that cannot be controlled by drainage or other methods
* Human immunodeficiency virus (HIV) infection or diseases associated with acquired immunodeficiency syndrome (AIDS)
* Active inflammatory bowel disease or other colorectal disease leading to chronic diarrhea
* Presence of CTCAE grade 2 or higher toxicity (other than anemia, alopecia and skin pigmentation) that has not recover due to any previous treatment
* Suspected allergies to any of the relevant drugs used in the study
* Pregnant or lactating
* Women of childbearing age (\<2 years after last menstrual period) or men of childbearing potential not using or refusing to use effective non-hormonal contraception
* Any unstable medical condition that affects patient safety and study compliance