The goal of a phase I clinical trial is to determine:

• A. The efficacy of a new agent in the treatment of specific types of cancer and to validate toxicity and dosage data
• B. The maximum tolerated doses of an investigational drug or combination of drugs and to identify dose-limiting toxicities
• C. The efficacy of a new agent in relation to standard existing treatments
• D. The maximum tolerated doses of an investigational drug or combination of drugs and to identify dose-limiting toxicities

Answer: (D)

Phase I trials focus on safety and dosing. The main aim is to find the highest dose that can be given with acceptable toxicity and to identify dose-limiting toxicities that prevent further dose increases. These dose-limiting toxicities define the maximum tolerated dose, which helps determine the dose to use in later testing (the recommended phase II dose). While collecting safety data, researchers may note early signals of activity, but proving effectiveness relative to standard treatments is not the primary goal at this stage. Efficacy is typically evaluated in phase II or III trials, after a safe and tolerable dose has been established.