Lucentis Plus Tagolimumab in PD-L1+, HR+/HER2- Advanced Breast Cancer After CDK4/6 Inhibitors

This study is a prospective, single-arm, multicenter Phase II trial designed to evaluate the efficacy and safety of Lucanisatuzumab in combination with Tagolisumab for the treatment of PD-L1-positive, HR+/HER2- advanced breast cancer patients who have failed prior CDK4/6 inhibitor therapy. The study plans to enroll 35 patients. The primary endpoint is the 6-month progression-free survival (PFS) rate assessed by the investigator (RECIST v1.1). Secondary endpoints include PFS, objective response rate (ORR), disease control rate (DCR), duration of response (DoR), overall survival (OS), and safety. An exploratory endpoint is to analyze the correlation between TROP2 and PD-L1 expression and efficacy. The treatment regimen consists of intravenous administration of Lucanisatuzumab (5 mg/kg, Q2W) combined with Tagolisumab (900 mg, Q2W). Treatment will continue until disease progression or occurrence of intolerable toxicity. Tumor assessments will be conducted every 6 weeks for the first 6 months, followed by every 12 weeks thereafter. Safety follow-up will occur after treatment completion, with telephone follow-ups every 3 months to collect survival and subsequent treatment information.