Abstract: The present invention relates to the use of a medicament in treatment of a tumor disease. In particular, the present invention provides the use of a biologically active conjugate represented by formula (I) in treatment of a tumor disease. The tumor disease particularly and preferably refers to an unresectable locally advanced or metastatic solid tumor that is refractory according to existing treatment standards, including but not limited to breast cancer, gastric cancer, lung cancer, ovarian cancer, urinary tract epithelial cancer, esophageal cancer, liver cancer, colorectal cancer, cervical cancer, endometrial cancer, pancreatic cancer, and brain tumor.