The study included a screening period, a treatment period, and a follow-up period.~Screening period: Subjects who are fully aware of the study and have signed an informed consent form should complete all screening procedures within 28 days before the first dose. Only eligible subjects can be enrolled in the study. Prior to enrollment, subjects should provide a test report confirming HER2 overexpression, defined in this study as IHC 2+ or 3+. Official reports from local hospitals or genetic testing companies are acceptable. All subjects provided adequate tumor tissue samples (archived or fresh biopsy samples) for evaluation and confirmation of HER2 expression and genetic testing (15 paraffin sections, 5-10um thick) before study administration. Considering the accessibility of clinical specimens, specimens are not mandatory.~Treatment period: Each treatment period was 14 days. Treatment regimen: Disitamab Vedotin, 2.5mg/kg, intravenously D1, once every 14 days (Q2W), combined with Zimberelizumab, 240mg, intravenously D1, once every 14 days (Q2W). Study treatment will be continued until the subject has an intolerable toxic effect, withdrawal of informed consent, and disease progression as confirmed by RECIST V1.1 (when the subject has disease progression as assessed by the investigator according to RECIST V1.1, the investigator will then assess whether the subject still has clinical benefit. If the subject is considered to have continued clinical benefit and meets the criteria for continuing treatment after disease progression, the subject may continue to receive the study drug; Treatment may be discontinued if the subject is no longer considered to have clinical benefit), or any other termination criteria specified in the protocol, whichever comes first. Within the time window specified in each cycle, the subject will complete a physical examination, laboratory tests, and other tests to assess the subject's safety. Imaging evaluations of tumors were performed every 6 weeks (42±3 days) during study treatment. Tumor evaluation must include all known lesions in the abdomen, pelvis, and other sites. Scans of suspected lesions and bone may be performed at the investigator's discretion. The assessment methods used throughout the study should be as similar as possible. The preferred method is enhanced computed tomography (CT) or magnetic resonance imaging (MRI).~Follow-up period: including safety follow-up and survival follow-up. At the end of treatment, all subjects will be followed up for safety until 28 days after the last dose. Subjects who discontinue treatment for reasons other than PD will be followed up at the planned frequency until PD occurs, consent is withdrawn, or follow-up is lost, whichever occurs first. After completion of treatment and safety follow-up, all subjects were followed for survival (OS data were collected every 3 months ±14 days) until death, withdrawal of informed consent, loss to follow-up, or termination of the study, whichever occurred first.
This is a multicenter, single-arm, open-labal, phase II clinical study with a planned enrollment of 31 patients with HER2-overexpressing unresectable locally advanced or metastatic biliary carcinoma who had failed previous treatment. The efficacy and safety of the study were evaluated according to RECIST V1.1.