Once the patient provides informed consent, he or she is enrolled in the study. Patients will be followed from enrollment until 1) 30 days after alpelisib treatment discontinuation, or 2) death, or 3) lost to follow-up, or 4) patient withdrawal, or 5) physician decision to end treatment/study, or 6) end of the study, whichever occurs first. The end of the study is defined as a maximum of 12 months after the date the last patient was enrolled (LPFV); if the last patient is still on treatment on that date, they will not be followed up any further
This is a prospective, multi-national, non-interventional study (NIS) collecting data from postmenopausal women, and adult men, with HR+, HER2- locally advanced or metastatic breast cancer whose tumor harbors a PIK3CA mutation, and who are treated with alpelisib in combination with fulvestrant after disease progression following endocrine therapy as monotherapy, in the real-world setting.