This study focuses on individuals with Metastatic Castration-Resistant Prostate Cancer, which is a type of advanced cancer that has spread to other parts of the body and continues to grow even after medical treatments have lowered hormone levels. The purpose of the study is to evaluate the effectiveness and safety of a combination treatment consisting of inavolisib and enzalutamide. In this trial, participants may receive the combination of these two drugs or be assigned to a different treatment chosen by their doctor, such as abiraterone or docetaxel. Abiraterone and enzalutamide belong to a group of medications known as androgen receptor pathway inhibitors, which work by blocking the hormones that help the cancer grow. Docetaxel is a type of chemotherapy used to kill cancer cells.

During the study, researchers will monitor how the cancer responds to the treatments. One way they track this is through radiographic progression-free survival, which measures the length of time during and after treatment that the cancer does not grow or spread as seen on imaging tests like scans. Other measurements include tracking prostate-specific antigen, which is a protein found in the blood that can indicate the presence or activity of prostate cancer. The study also looks at the overall length of time patients live and monitors any side effects or adverse events that may occur during the course of the medication.