TQB-2930

Primary objective: To demonstrate the efficacy of TQB2930 combined with chemotherapy selected by the investigator versus trastuzumab combined with chemotherapy selected by the investigator in subjects with HER2-positive advanced breast cancer who have received at least 2 lines of anti-HER2 therapy at the advanced stage through progression-free survival (PFS) assessed by an independent imaging review committee (IRC). Secondary objectives: To demonstrate the efficacy of TQB2930 combined with chemotherapy selected by the investigator versus trastuzumab combined with chemotherapy selected by the investigator in subjects with HER2-positive advanced breast cancer who have received at least 2 lines of anti-HER2 therapy at the advanced stage through PFS assessed by the investigator, duration of response (DOR) assessed by the investigator and IRC, objective response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR), and overall survival (OS). To evaluate the safety of TQB2930 combined with chemotherapy selected by the investigator versus trastuzumab combined with chemotherapy selected by the investigator in subjects with HER2-positive advanced breast cancer who have received at least 2 lines of anti-HER2 therapy at the advanced stage. To evaluate the population pharmacokinetic (PK) characteristics of TQB2930 in combination with chemotherapy selected by the investigator in subjects with HER2-positive advanced breast cancer who have received at least 2 lines of anti-HER2 therapy in the advanced stage. To evaluate the immunogenicity of TQB2930 in combination with chemotherapy selected by the investigator in subjects with HER2-positive advanced breast cancer who have received at least 2 lines of anti-HER2 therapy in the advanced stage.