Clinical trials can be divided into how many phases?

Clinical trials are typically classified into four distinct phases, each serving a specific purpose in the evaluation of a new drug or treatment approach.

In Phase I, the focus is on assessing the safety and tolerability of the treatment in a small group of healthy volunteers or participants with a targeted condition. This phase aims to determine the appropriate dosage range and identify any side effects.

Phase II expands the participant group and emphasizes the treatment's efficacy. Here, researchers also continue to monitor safety and begin to gather preliminary data regarding how well the treatment works.

Phase III involves a much larger population and is crucial for comparing the new treatment against standard treatments or a placebo. This phase provides the most robust data regarding the treatment's benefits and risks before the drug can be submitted for regulatory approval.

Finally, Phase IV occurs after the drug has been approved and is on the market. This phase focuses on post-marketing surveillance to monitor the long-term effects and effectiveness of the treatment in the general population.

This structured approach across the four phases ensures not only the safety of new therapies but also provides evidence of their efficacy, helping to guide clinical practice and inform patients.