Researchers are looking for new ways to treat metastatic castration-resistant prostate cancer (mCRPC). Researchers have designed a study medicine called ifinatamab deruxtecan (also called I-DXd or MK-2400) to treat mCRPC. The goal of this study is to learn if people who receive I-DXd live longer overall and live longer without the cancer growing or spreading than people who receive chemotherapy.

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).