Steps followed in clinical trial research to obtain sufficient evidence that a process
would be useful in medical treatment.
There are 5 phases of clinical trials:
- Phase 0:
The first clinical trials done among people. They aim to learn how a drug is
processed in the body and how it affects the body. In these trials, a very small dose of a
drug is given to about 10 to 15 people.
- Phase I:
Tests the safety of a drug in healthy volunteers or subjects with indications. The
aim is to find the best dose of a new drug with the fewest side effects. The drug is tested in
a small group of 15 to 30 patients. Low doses are given initially to a few patients, higher
doses are given in others until desired effect is reached or undesirable effects seen.
- Phase II:
Further assess safety of a drug in a large sample of patients. The study drug is tested
among patients with a specific cancer type and new combinations of drugs may be used.
- Phase III:
Compare a new drug to the standard-of-care drug. These trials assess the side effects
of each drug and which drug works better. Phase III trials enroll 100 or more patients.
- Phase IV:
Test new drugs approved by the FDA. It studies the side effects caused over time by
a new treatment after it has been approved and is on the market. The drug is tested in
several hundreds or thousands of patients. This allows for better research on short-lived and
long-lasting side effects and safety.