Which phase of clinical trials focuses on safety testing of a new treatment?

The focus of Phase I clinical trials is primarily on safety testing of a new treatment. In this initial phase, the treatment is administered to a small group of participants, typically between 20 to 80, to evaluate its safety profile, determine a safe dosage range, and identify side effects. This stage is crucial as it helps establish the treatment's tolerance levels in humans before it is tested on larger populations.

During Phase I, researchers monitor participants closely, collecting detailed data on how the body responds to the medication, including any adverse reactions or side effects. The findings from this phase form the foundation for subsequent trials, which may examine the effectiveness of the treatment further. Phase II trials, for example, expand on this by exploring the treatment's efficacy and optimal dosing after safety has been established. Therefore, Phase I is essential for ensuring the new treatment is safe to proceed to the next level of clinical research.