What are clinical trials for?
Are clinical trials safe?
How are clinical trials set up?

The 4 phases of clinical research

Before a medicine can be tested in a clinical trial, it must first be tested in animals to confirm that it is safe. Testing new medicines usually goes through the following 4 phases.

 
Phase
I

Basic safety

These trials test a new medicine to see if it is safe. In this phase, a small number of people, who may be healthy, are given the medicine. When trial doctors are sure it is safe, the medicine can move to Phase II.

Phase
II

Does the medication work?

These trials test the new medicine on a larger group of people (usually a few hundred) with a specific disease for a longer time. This is done to see if or how the medicine works. This is also known as a medicine’s efficacy.

Phase
III

Testing in a larger group

These trials test medicines in even larger groups of people (typically several hundred) with a specific disease. This phase compares the new medicine to the usual medicine used for the disease, or to a placebo (dummy medicine that doesn’t have active ingredients).

Doctors will often use the “blinded” method for Phase II and Phase III trials. This means that neither the participant nor the doctor will know which medicine or placebo the volunteer receives.

Phase
IV

Post-approval testing

In these trials, the medicine tested has already been approved for use. Phase IV trials include the largest group of participants (usually several hundred to thousands of volunteers). Phase IV trials are sometimes called Post Marketing Surveillance Trials.

 

Did you know?

Interested in participating?