Clinical trials are research studies conducted with the hopes of developing safer and more effective means to treat serious illnesses. They are designed with specific objectives in mind, ranging from finding better ways to prevent disease to discovering new means to diagnose and treat disease.
THE PHASES OF CLINICAL TRIALS IN THE UNITED STATES
Before the U.S. Food and Drug Administration (FDA) can approve a new treatment for human use, it must undergo extensive testing to determine its safety and efficacy in treating a specific disease. Drug development involves three stages of human clinical testing: Phase 1, Phase 2, and Phase 3. Human clinical trials typically follow years of preclinical development in laboratories and animal studies.
Preclinical Study: Initial study conducted to determine potential new treatments for specific disease indications. Animal models are frequently used to help determine a treatment's safety prior to introducing it to humans.
Phase 1 Trial: Clinical trial conducted to evaluate the safety of a drug or therapy. How a drug should be administered (e.g. oral, injection) and dose levels are also evaluated. Phase 1 trials typically involve a small group ranging from 5 to 50 patients, depending on the disease indication.
Phase 2 Trial: Clinical trial conducted to further evaluate the safety of a drug or therapy and to evaluate its efficacy. In addition, researchers focus on determining optimal dose levels. Phase 2 trials typically involve a larger group than Phase 1 trials, approximately 15 to 200 patients, depending on the disease indication.
Phase 3 Trial: Clinical trial conducted to confirm the efficacy of a new drug or therapy. Trial participants are usually included in one of two study groups: one which will receive the new drug being evaluated, and one that receives the already approved, current standard of treatment. Phase 3 trials can enroll anywhere from 50 to 5,000 patients.
During Phase 3 trials, study sponsors will begin to assemble an application [either a Biologics License Application (BLA) or a New Drug Application (NDA)] for submission to the FDA demonstrating the investigational drug or therapy's safety and efficacy based on the data gathered from the clinical trials. The FDA will evaluate the submission and make a determination as to the approvability of the application. Drugs and therapies that are approved by the FDA can then be commercially marketed throughout the United States.
Note: While patient numbers in clinical trials may vary greatly depending upon trial design or disease indication, these numbers provide average ranges of trial sizes for the abovementioned trial phases
How to Become Involved in a Clinical Trial
There are numerous resources on the Internet that list clinical trials being conducted in multiple disease indications. The www.clinicaltrials.gov web site is a good place to start.
