This study is looking at prostate cancer and how certain medications used to treat this disease might affect the body’s processing of another medicine. The study involves patients who are about to start treatment with one of two medications called enzalutamide or apalutamide, which are types of antihormonal therapy that work by blocking male hormones that can help prostate cancer grow. During the study, participants will also receive dexamethasone, which is a type of medicine called a glucocorticoid that helps reduce inflammation and is often used alongside cancer treatments. The purpose of the study is to see how much enzalutamide and apalutamide change the way the body processes dexamethasone when these medicines are taken together.

Participants will receive dexamethasone at different times during the study to measure how much of the medicine stays in the blood. The first measurement will be taken before starting the antihormonal therapy, and then again after the body has adjusted to the regular use of enzalutamide or apalutamide. Blood samples will be collected to measure the amount of dexamethasone present over time, which helps researchers understand if the antihormonal medicines are affecting how the body breaks down the glucocorticoid. Later in the study, participants may receive a higher dose of dexamethasone to see if increasing the amount can make up for any changes caused by the antihormonal treatment.

The study will also look at whether any unwanted effects occur when dexamethasone is given on three separate occasions during the treatment period. Researchers want to understand if the combination of these medicines requires any adjustments to dosing to ensure patients receive the full benefit of their corticosteroid treatment while taking their cancer therapy. The information gathered will help doctors better understand how these medicines interact in the body and whether treatment plans need to be modified when these medications are used together.