Phase I
Phase I trials are the first time a new treatment is tested in people, with a small group of participants and a sharp focus on safety.
Phase II
Once a treatment has passed its first test for safety in a small group, it enters the next step: Phase II clinical trials. Now, the question shifts from “Is it safe?” to “Does it work?”
Phase III
By the time a new treatment reaches Phase III, it’s already shown promise. It’s been through early testing for safety and effectiveness. Now, it faces the biggest and most important question yet: Is it better than what we already have?
Phase IV
The treatment has been approved. It’s on the market. Doctors are prescribing it. So… is the research over? Not even close. That’s where Phase IV clinical trials come in.