About Clinical Trials
What is a Clinical Trial?
Types of clinical trials
- Phase I trials help determine the optimal amount or dose of a new therapy that can be given safely to participants. These studies typically have a small number of participants, often fewer than 20.
- Phase II studies continue to evaluate safety, but also begin to assess a therapy’s effectiveness. These trials typically have more participants than phase I trials.
- Phase III studies compare the effectiveness of a new therapy or combination of therapies with a standard treatment, and may include hundreds or thousands of participants.
- Phase IV trials continue to study the safety and effectiveness of a treatment after it has been approved by the FDA.