Using the chemicals in the human body to predict the optimal dose of orally administered anticancer drugs.

This study is looking for natural body chemicals (called endogenous metabolites) that can predict how quickly a healthy person breaks down certain anti-cancer drugs. An enzyme called CYP3A4 processes many medications in the liver, but people vary widely in how active this enzyme is. Identifying a reliable body marker for CYP3A4 activity could help doctors personalise cancer drug doses so each patient gets the right amount — not too much and not too little. You may be eligible if: - You are male - You are between 21 and 35 years old - You are in good health - You are a non-smoker - Your BMI is between 18 and 30 You may NOT be eligible if: - You smoke cigarettes - You have taken any prescription, over-the-counter, herbal, or recreational drugs in the last 7 days - You have drunk grapefruit juice in the last 48 hours - You have had a previous allergic reaction to any study drug Talk to your doctor about whether this trial might be right for you.