What is the main focus of Phase I clinical trials?

Phase I clinical trials primarily focus on determining the safety and adverse effects of a new drug or treatment. These trials are usually the first step in testing a new drug in humans after initial laboratory research, and they typically involve a small number of healthy volunteers or patients. The primary goal is to assess how the drug interacts with the human body, including its pharmacokinetics (how the drug is absorbed, metabolized, and excreted) and any potential side effects that may occur. This stage is crucial as it helps to identify the safety profile of the drug before it is tested further in larger populations in subsequent phases.

While dosage information is a consideration in Phase I trials, the main emphasis is on safety rather than determining the optimal dosage or assessing effectiveness. Recruiting a large patient population is characteristic of later phases of clinical trials, as Phase I focuses on smaller groups for safe testing. Thus, the focus on safety and adverse effects is foundational to the purpose of Phase I trials.