The Efficacy and Safety of Fluzoparib Plus Irinotecan as Second-line Treatment in Patients With Homologous Recombination Deficiency (HRD) Metastatic Colorectal Cancer.

Inclusion Criteria:

* 18-75 years；
* Histological or cytological confirmed metastatic colorectal cancer;
* HRD alterations（inclued BRCA1/2、ATM、CDK12、PALB2、Check2、RAD51C、RAD51D etc.）；
* Intolerability toxicity occurs 8 weeks within first-line therapy;
* ECOG PS 0-1;
* Adequate hepatic, renal, heart, and hematologic functions;
* Negative serum pregnancy test at screening for women of childbearing potential;
* Informed consent was signed before the study began.

Exclusion Criteria:

* Prior treatment with PARPi drugs；
* Symptomatic brain or meningeal metastases；
* Patients have received local radiotherapy within 1 month prior to treatment;
* Patients who had active bleeding or coagulopathy before enrollment, had a tendency to bleed, or were receiving thrombolytic therapy and were considered by the investigator to be ineligible for enrollment;
* Women who are pregnant (with a positive pregnancy test before medication) or breastfeeding;
* Expected survival \<3 months;
* Received other investigational drugs within 4 weeks prior to treatment;
* Patients who had active uncontrollable neurological, mental disease or mental disorder, poor compliance, unable to cooperate and describe the treatment response;
* Allergy to the study drug or any of its excipients;