PD-L1 Inhibitor + RT ± Ursodeoxycholic Acid in Recurrent/Metastatic HER2-Neg Breast Cancer

Summary

Experimental Group Adebrelimab (PD-L1 inhibitor) 1200 mg on Day 1, every 3 weeks. Radiotherapy (Stereotactic Body Radiation Therapy, SBRT) with a dose of 24 Gy/3 fractions within 3 weeks after the first immunotherapy dose. Ursodeoxycholic Acid (UDCA) 250 mg twice daily, starting 7 days before radiotherapy and continuing for 1 month after radiotherapy completion. Control Group Adebrelimab 1200 mg on Day 1, every 3 weeks. SBRT with a dose of 24 Gy/3 fractions within 3 weeks after the first immunotherapy dose. Chemotherapy is permitted during the study in both groups. The decision to use chemotherapy will be made by the treating physician based on the patient's individual condition and prior treatment history. Primary Endpoint Objective Response Rate (ORR) of lesions outside the radiotherapy field, assessed by RECIST 1.1 criteria. Secondary Endpoints Disease Control Rate (DCR) of lesions outside the radiotherapy field. Safety profile (≥3 toxicities). ORR of lesions within the radiotherapy field. Distant metastasis rate outside the radiotherapy field. Progression-Free Survival (PFS) and Overall Survival (OS). Safety Monitoring Adverse events and serious adverse events (SAE) will be closely monitored and reported according to the protocol. Treatment will be discontinued if predefined criteria for stopping are met. Study Duration The study will include a screening period, a treatment period, and a follow-up period with regular assessments every 2 cycles of immunotherapy until death occurs.

Timeline

Start

2025-02

Primary completion

2028-12

Completion

2029-12

Drugs

Indications