This study is for people with a certain type of breast cancer. It compares two treatments: inavolisib plus fulvestrant and alpelisib plus fulvestrant. Breast cancer is when cells grow uncontrollably in the breast. The study is for those whose cancer has progressed (gotten worse) during or after other treatments. The cancer is hormone receptor (HR)-positive, meaning it grows in response to hormones, but it's HER2-negative, meaning it doesn't grow from a protein called HER2. Participants must have a specific mutation in a gene called PIK3CA. This is a Phase III study, which means it's testing how well the treatment works and its safety.

Key Points:

• The study lasts until the necessary data is collected to determine the treatment's effectiveness and safety.
• Participants will receive either inavolisib or alpelisib with fulvestrant, and regular medical visits are needed.
• There may be risks or side effects, and participants should discuss these with their doctors.