About Clinical Studies

Before a drug or treatment can be approved for use by the FDA, there must be proof that the investigational drug works and is considered safe enough for the tested population. Clinical studies are research studies that investigate the potential of the investigational drug to see whether it is safe and effective. In a clinical study, volunteer participants receive specific interventions according to the research plan or protocol.

Clinical studies used in drug development are sometimes described by phase. These phases are defined by the Food and Drug Administration (FDA). Each phase has a different purpose and helps researchers answer different questions.1

1

Phase One

Researchers test an investigational drug in a small group of people for the first time. The purpose is to study the investigational drug or treatment to learn about safety, identify side effects, and examine dosing amount and frequency.

Phase One
2

Phase Two

The investigational drug is given to a larger group of people who have the disease being studied. The purpose of this phase is to further evaluate the safety and the potential efficacy of the investigational drug or treatment.

Phase Two
3

Phase Three

The investigational drug or treatment is given to large groups of people with the disease being studied to measure its effectiveness and side effects, compare it with the standard of care or similar treatments, and collect information that will allow the new drug or treatment to be used safely.

Phase Three
4

Phase Four

After a drug is approved by the FDA and made available to the public, researchers track its safety in the general population, seeking more information about a drug or treatment’s benefits, and optimal use.

Phase Four