Inclusion Criteria:  Confirmed diagnosis of hormonal receptor-positive (HR+)/Her2-negative breast cancer No prior systemic anti-cancer therapy for advanced HR+ disease except tamoxifen treatment in adjuvant sitting If the patient is pre-/peri- menopausal, a luteinizing hormone-releasing hormone (LHRH) agonist will be given for at least 28 days before randomization or ovarian ablation or suppression by surgery or radiotherapy Measurable disease defined by RECIST version 1.1, Eastern Cooperative Oncology Group (ECOG) 0-1 Adequate organ and marrow function.  Exclusion Criteria:  Patients with advanced, symptomatic visceral spread (visceral crisis) Patients diagnosed with central nervous system metastases Second primary malignancy