What is a clinical trial?
Types of clinical trials
Bioequivalence trials—to compare two drugs with different trademarks to verify that they work in the body in identical ways and have equal activity.
Treatment trials—to gather information about the efficacy and risks of experimental drugs or medical devices, or to compare experimental therapies with existing ones to decide which is the best treatment for a particular condition;
Screening trials—to use imaging, laboratory or genetic tests to identify a disease before symptoms occur;
Diagnostic trials—to evaluate new tests that could identify a disease in its early stages; usually people must show symptoms to qualify for participation;
Prevention trials—to determine if positive lifestyle changes, like a more nutritional diet, or vitamins and vaccines could reduce the risk of illness or prevent the recurrence of a disease;
Quality of life trials—to find ways of improving life for sufferers of chronic health problems or life-threatening diseases;
Clinical trial phases
- Phase 1—evaluated in a small group of often healthy people (20 to 80) to check its safety and side effects and to find the correct drug dosage;
- Phase 2—evaluated in a bigger group of people (100 to 300) over a longer period to check if it is effective and safe;
- Phase 3—evaluated in a large group of people (up to 3,000) and comparing it to a placebo or standard treatment to compare its safety and efficacy, after which medical regulatory bodies such as the U.S. Food and Drug Administration (FDA) will approve it if the results are positive;
- Phase 4—takes place after regulatory approval to monitor safety and efficacy in large, diverse populations over a relatively long period of time.