This study investigates treatments for men with metastatic castration-resistant prostate cancer (mCRPC) who have DNA repair defects. The purpose is to assess the effectiveness of two drugs that are approved by the US FDA, both individually and in combination. Metastatic castration-resistant prostate cancer is a type of prostate cancer that continues to grow even when the amount of testosterone in the body is reduced to very low levels. DNA repair defects refer to problems in the body's ability to fix damaged DNA, which can affect cancer growth.

Participants in this study may receive one of the following: abiraterone with prednisone, olaparib, or a combination of abiraterone/prednisone with olaparib. A placebo is not mentioned in this study. The study aims to measure progression-free survival (PFS), which is the length of time during and after treatment that a patient lives with the disease without it getting worse.

• Who can participate: Men aged 18 years or older with a diagnosis of prostate adenocarcinoma are eligible to participate. For a full list of criteria, please refer to the study's official page.
• Study details: Participants will receive either investigational medications or a combination of these treatments. The study focuses on assessing the effectiveness of these treatments in individuals with specific DNA repair defects.