Study of 2 Ribociclib Doses in Combination With Aromatase Inhibitors in Women With HR+, HER2- Advanced Breast Cancer

Patients were assigned at visit Cycle 1 Day 1 to one of the following two treatment arms in a ratio of 1:1: * Experimental arm: Ribociclib 400 mg (2 × 200 mg tablets by mouth) QD on Days 1 to 21 of a 28-day cycle, followed by 7 days off ribociclib (Days 22 to 28) in combination with ET consisting of: • For postmenopausal women: * Letrozole 2.5 mg by mouth QD continuously or anastrozole 1 mg by mouth QD continuously • For premenopausal women: * Letrozole 2.5 mg by mouth QD continuously or anastrozole 1 mg by mouth QD continuously, combined with goserelin 3.6 mg subcutaneously once every 4 weeks. * Control arm: Ribociclib 600 mg (3 × 200 mg tablets by mouth) QD on Days 1 to 21 of a 28-day cycle, followed by 7 days off ribociclib (Days 22 to 28) in combination with ET consisting of: * For postmenopausal women: \~ Letrozole 2.5 mg by mouth QD continuously or anastrozole 1 mg by mouth QD continuously. * For premenopausal women: * Letrozole 2.5 mg by mouth QD continuously or anastrozole 1 mg by mouth QD continuously, combined with goserelin 3.6 mg subcutaneously once every 4 weeks. Participants received study treatment until disease progression (radiologically documented according to RECIST 1.1 criteria), unacceptable toxicity, death, or discontinuation from the study treatment for any other reason. For participants who discontinued treatment for reasons other than documented disease progression, death, lost to follow-up, or withdrawal of consent, tumor assessments continued to be performed until disease progression, death, lost to follow-up, or withdrawal of consent (post-treatment efficacy follow-up).