A Randomized, Open-Label, Multicenter Phase II Clinical Trial: Comparing the Efficacy and Safety of Different Doses of BL0175 Injection in Treating Postmenopausal Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Locally Advanced or Metastatic Breast Cancer Patients
The goal of this clinical trial is to compare the objective response rates (ORR) of different doses of BL0175 in patients with postmenopausal hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative locally advanced or metastatic breast cancer. The main questions it aims to answer are: 1. Which dose level of BL0175 demonstrates the optimal ORR? 2. What is the recommended phase 3 dose (RP3D) based on efficacy and safety data across the tested dose levels?
• Voluntary participation in the trial, understanding the specific procedures of the trial, and willing to sign a written informed consent form.
• Age ≥ 18 years.
• HR positive, HER2 negative, with locally advanced or metastatic breast cancer in postmenopausal patients during or after endocrine therapy.
• The blood pregnancy test result during the screening period must be negative (if the postmenopausal state is caused by GnRH agonists).
• If the postmenopausal state is caused by GnRH agonists, the trial participants must agree to take effective contraceptive measures from the time of enrollment until at least 2 years after the last administration of the study treatment. For patients with breast cancer, the use of estrogen-based hormonal contraceptive methods (including hormone-type intrauterine devices) is not allowed, while the efficacy of progestin-based hormonal contraceptive methods is currently unclear. Effective contraceptive measures include: a. Complete abstinence (if it is their preferred regular lifestyle); b. Intrauterine device; c. Bilateral tubal ligation; d. The partner has undergone vasectomy and confirmed no sperm; e. Dual barrier method (male condom combined with cervical cap, vaginal diaphragm, or contraceptive sponge in combination with spermicidal agent).
• At least one measurable lesion exists.
• The Eastern Cooperative Oncology Group (ECOG) status score at screening must be ≤ 1.
• Life expectancy ≥ 12 weeks.