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;