Efficacy and Safety of LY01005 in Patients With Breast Cancer Compared to ZOLADEX®

This is a multicenter, randomized, open-label, active comparator-controlled phase Ⅲ trial using non-inferior design. A total of 188 patients with breast cancer who are suitable for endocrine therapy will be enrolled into the screening period from D-28 to D-1 before administration. Eligible subjects will be randomized in a 1:1 ratio to receive LY01005 3.6 mg intramuscularly or ZOLADEX ® 3.6 mg subcutaneously once every 28 days for three doses until intolerable toxicity, disease progression requiring other anti-tumor treatments, withdrawal of consent, loss to follow-up, death or the end of the whole study, and stratified according to history of chemotherapy (yes vs. no) and age (\<45 vs. ≥45 years old). And all subjects will be also treated with tamoxifen orally twice per day (10 mg/tablet, 1 tablet/time). Blood samples will be collected at the specified time points of the study to detect serum E2, LH and FSH. Safety evaluation (including vital signs, physical examination, laboratory tests, 12 ECG, adverse events, etc.) will be conducted as required in the protocol. Additional blood samples will be collected from 12 subjects (PK subgroup) who are randomized to LY01005 group to assess the PK and PD characteristics of LY01005 in patients with breast cancer.