What is a clinical trial?
U.S. Food and Drug Administration (“FDA”) approval is required prior to marketing a pharmaceutical product in the United States. To obtain this approval the FDA requires clinical trials to demonstrate the safety, efficacy, and potency of the product candidates. Clinical trials are the means by which experimental drugs or treatments are tested in humans. New therapies typically advance from laboratory (research) testing through animal (preclinical) testing and finally through several phases of clinical (human) testing. Upon successful completion of clinical trials, approval to market the therapy for a particular patient population may be requested from the FDA in the United States and/or its counterparts in other countries.
Clinical trials are divided into 4 phases.
- Phase I trials: These trials are the first time a new drug or treatment is given to humans. Phase I studies are normally carried out in a small number of healthy volunteers (20-80 people) in order to find out how safe a treatment is. These studies may look at the way a new drug should be given (by mouth, injected into blood, etc.), how often it should be given and at what dose. Phase I trials may also involve patients for whom standard therapies have failed and for whom no other therapies are left.
- Phase II trials: These trials involve large numbers of people (100-300). Phase II trials continue to look at the safety of the therapy but may also test how well the new drug or treatment works in different disease types.
- Phase III trials: These are larger studies (1000-3000) which look at how well a new drug or treatment works in comparison to current therapies to see which treatment is better.
- Phase IV trials: These trials are usually carried out after the drug or treatment has been approved by the FDA and is readily available for use in the general patient population. The purpose of Phase IV trials is to continue to study the effects of the drug or treatment on different populations and to look for side affects associated with long-term use.
For more information, please visit www.clinicaltrials.gov.
For booklets on:
For booklets on:
- Volunteering for a Clinical Trial: Your Guide to Participating in an Important Research Study
- A Word From Study Volunteers: A Look at the Experiences of People Who Have Participated in Recent Clinical Trials
- Informed Consent: A Guide to the Risks and Benefits of Volunteering for a Clinical Trial