Phase 1 Single-arm, Open-label, Multicenter Trial to Evaluate Ovarian Suppression Following Subcutaneous ZOLADEX 10.8 mg in 2 Parallel Cohorts of Premenopausal Women With Early-stage and Advanced Hormone Receptor-positive (HR+) Breast Cancer

Inclusion Criteria: 1. Age and gender: Female participants aged 18 to 55 years, inclusive. 2. Hormone receptor positive (HR+): Either estrogen receptor positive (ER+) or progesterone receptor positive (PR+) breast cancer, defined as 1% to 100% of tumor nuclei are positive for ER or PR via immunohistochemistry. 3. Participants must be of premenopausal status. 4. Recent radiotherapy: 1. Prior radiotherapy is allowed. 2. All radiotherapy-related toxicities (except alopecia) must have recovered to Common Terminology Criteria for Adverse Events (CTCAE) v6.0 Grade ≤1 before trial enrollment.…