A clinical trial, also referred to as a clinical study or research study, is designed to determine if a new drug or treatment will work to address a condition, treat a disease, enhance a procedure or will be of benefit to patients. In addition, clinical trials help address adverse events or side effects and eventually determine the possible release date of new drugs, surgical equipment and devices.
Clinical trials are commonly divided into four phases. If the product successfully passes through the first three phases, it will usually be successfully approved by regulatory organizations for use in the general population
A Phase I study is the first use of a new drug, device or instrument in humans and is used to test for safety and side effects, and to determine how the product should be used or delivered. Only a limited number of patients are accepted for participation in Phase I trials.
If the Phase I trial shows safety, a Phase II trial is initiated to investigate the ideal dosing range of or usage parameters of the potential product. The future product is tested in a larger number of patients to determine how well it works, and to determine other possible, less common side effects.
In a Phase III trial for pharmaceuticals, experimental treatments are compared to placebos. Because patients who participate in Phase III trials are randomly chosen to receive the experimental treatment or to receive placebo, they will not know which group they have been chosen for-placebo or experimental treatment. The purpose of a Phase III trial is to determine efficacy, or if patients receiving the experimental therapy do better than those who do not.
A Phase III trial for ophthalmic surgical devices evaluates the surgical impact and results, as well as any adverse events or side effects, of using a particular instrument, device or material in a surgical procedure. These results are reported to regulatory bodies as required for evaluation.
A Phase IV clinical trial may be conducted to continue to evaluate extensions of the safety and efficacy of therapies that are already approved by regulatory bodies and available for general use.