Study Assessing the Efficacy and Safety of Treatment With Alpelisib Plus Fulvestrant in Japanese Men and Postmenopausal Women With Advanced Breast Cancer

"\[Part 1\] Alpelisib administered at 200 mg (DL 1), 250 mg (DL 2) or 300mg (DL 3) orally once daily on a continuous dosing schedule starting on Cycle 1 Day 1 in a 28 day cycle.~If DL 1 is tolerated, the alpelisib doses of 250 mg will be investigated. If DL 2 is tolerated, the alpelisib doses of 300 mg will be investigated.~\[Part 2\] In the Part 2, participants will be enrolled into Cohort 2 (CDK4/6 inhibitor naive) and Cohort 3 (CDK4/6 inhibitor pre-treated) in parallel and alpelisib will be administered at the recommended dose identified in Part 1."

Fulvestrant is administered at a dose of 500 mg intramuscular on Cycle 1 Day 1, Day 15, and Day 1 of every cycle thereafter (where a cycle is 28 days).