A Randomized, Open-Label, Multicenter Phase II Clinical Study of Different Doses of Trastuzumab Rezetecan for Injection or Trastuzumab Deruxtecan for Injection in the Treatment of Unresectable Locally Recurrent/Metastatic Breast Cancer With HR-Positive and HER2-Low Expression
The study is designed to compare the efficacy and safety of different dose groups of Trastuzumab Rezetecan or Trastuzumab Deruxtecan in patients with HR-positive, HER2-low unresectable locally recurrent/metastatic breast cancer. It will also exploratively evaluate the pharmacokinetic profile and immunogenicity of Trastuzumab Rezetecan.
• Female aged 18 to 75 years (inclusive).
• Unresectable locally recurrent or metastatic breast cancer.
• Prior therapy must meet the following: No prior chemotherapy for recurrent/metastatic disease. Must have received at least one prior line of endocrine therapy for recurrent/metastatic disease with disease progression, and the investigator judges that further benefit from endocrine therapy is not possible.
• Documented radiological disease progression (during or after the most recent therapy).
• ECOG performance status of 0 or 1.
• Life expectancy ≥ 12 weeks.
• At least one extracranial measurable lesion as a target lesion according to RECIST v1.1 criteria.
• Adequate function of major organs.
• Pregnancy and contraception: Women of childbearing potential (WOCBP) must agree to use highly effective contraception from study screening until 7 months after the last dose of study drug and agree not to breastfeed; serum pregnancy test result must be negative within 7 days before the first dose.
⁃ The patient voluntarily participates in this study, signs the informed consent form, has good compliance, and is willing to cooperate with visits and study-related procedures.