Metastatic Prostatic Adenocarcinoma

This study is being done to answer the following question: can the chance of prostate cancer growing or spreading be lowered by adding a drug to the usual combination of drugs?
This study would like to find out if this approach is better or worse than the usual approach for prostate cancer.
The usual approach for patients who are not in a study is hormone treatment with Androgen Deprivation Therapy (ADT) and Androgen-Receptor Pathway Inhibitor (ARPI).

This phase III trial compares the effect of adding docetaxel to hormonal therapy and apalutamide versus hormonal therapy and apalutamide alone in treating patients with prostate cancer that has spread from where it first started (primary site) to other places in the body (metastatic). Docetaxel is in a class of medications called taxanes. It stops tumor cells from growing and dividing and may kill them. Hormone therapy for prostate cancer, also called androgen deprivation therapy (ADT), uses surgery or drugs to lower the levels of male sex hormones in a man's body. This helps slow the growth of prostate cancer. Apalutamide is in a class of medications called androgen receptor inhibitors. It works by blocking the effects of androgen (a male reproductive hormone) to stop the growth and spread of tumor cells. Giving docetaxel in addition to the usual treatment of hormonal therapy and apalutamide may work better in treating patients with metastatic prostate cancer than the usual treatment alone.