This clinical trial is focused on studying treatments for Metastatic Castration-Resistant Prostate Cancer, a type of prostate cancer that continues to grow and spread even when the amount of testosterone in the body is reduced to very low levels. The study is testing a combination of therapies that include Pembrolizumab (also known as MK-3475), which is a type of immunotherapy that helps the immune system fight cancer. Other medications being studied in combination with Pembrolizumab include Abiraterone, Enzalutamide, Docetaxel, Carboplatin, Etoposide, Olaparib, Lenvatinib, and Belzutifan. Some of these medications are given as tablets, while others are administered through an infusion into a vein.

The purpose of this study is to evaluate the safety and effectiveness of these combination therapies. Participants will receive either the combination therapy or a placebo. The study will monitor the participants’ response to the treatment, including any changes in their prostate-specific antigen (PSA) levels, which is a marker used to track prostate cancer. The study will also look at how long the participants live and how long they respond to the treatment. Participants will be closely monitored for any side effects or adverse events during the study.

The study will take place over several years, with participants receiving treatment and being monitored regularly. The goal is to find out if these combination therapies can help control the cancer and improve the quality of life for those affected by this type of prostate cancer. The study will provide valuable information that could lead to new treatment options for patients with metastatic castration-resistant prostate cancer.