Clinical Trials

Definition:
Clinical trials are tests of new therapies such as medications and surgeries on humans. There are three phases of clinical trials for medications in the United States:

• Phase I trials ensure the safe and effective use of the therapy. Generally using a small number of participants, Phase I trials for medications test a range of dosages.

• Phase II trials test whether the medication is helpful in treating the targeted illness. These trials may also help determine other factors such as what types of patients may find the drug more effective than others.

• Phase III trials are the largest and may take months or years to complete. The new medication is tested against existing drugs and placebo. A Phase III trial must show a drug's effectiveness and possible negative reactions.

All three phases of drug trials must be completed before a manufacturer may apply for FDA approval of a new medication.

In addition, a medication that has been approved by the FDA for one illness, such as depression, must complete new trials for approval to treat another illness, such as bipolar disorder.