SOLAR 1: This phase III trial is evaluating fulvestrant treatment alone and in combination with alpelisib in men and post- menopausal women who have been diagnosed with hormone receptor positive, HER 2 - advanced breast cancerA Phase III Randomized Double-blind, Placebo Controlled Study of Alpelisib in Combination With Fulvestrant for Men and Postmenopausal Women With Hormone Receptor Positive, HER2-negative Advanced Breast Cancer Which Progressed on or After Aromatase Inhibitor Treatment

Exclusion

• Patient with symptomatic visceral disease or any disease burden that makes the patient ineligible for endocrine therapy per the investigator's best judgment
• Patient has received prior treatment with chemotherapy (except for neoadjuvant/ adjuvant chemotherapy), fulvestrant, any PI3K, mTOR or AKT inhibitor (pre-treatment with CDK4/6 inhibitors is allowed)
• Patient with inflammatory breast cancer at screening
• Patients with Child pugh score B or C
• Patients with an established diagnosis of diabetes mellitus type I or not controlled type II
• Patient has Eastern Cooperative Oncology Group (ECOG) performance status 2 or more
• Patient with CNS involvement unless he/she is at least 4 weeks from prior therapy completion to starting the study treatment and has stable CNS tumor at time of screening and not receiving steroids and/or enzyme inducing ant-epileptic medications for brain metastases
• Patient has participated in a prior investigational study within 30 days prior to enrollment or within 5 half-lives of the investigational product, whichever is longer
• Patient has a history of acute pancreatitis within 1 year of screening or a past medical history of chronic pancreatitis
• Patient who relapsed with documented evidence of progression more than 12 months from completion of (neo)adjuvant endocrine therapy with no treatment for metastatic disease

Other protocol-defined inclusion/esclusion criteria may apply.