What Are Phase III Clinical Trials?

Clinical trials test the efficacy and safety of newly developed medical drugs and devices. The U. S. Food and Drug Administration analyzes the data from clinical trials to determine whether the drug or device is safe for use in medical therapies. Each phase of a clinical trial is defined by how the drug or device is to be evaluated; the data from each phase must be approved by the FDA before the next phase can begin.

Phase 1

• Before a pharmaceutical or biotech company can begin phase III clinical trials, the safety and efficacy of the drug must be determined. Phase 1 trials typically involve the recruitment of a small group of healthy volunteers to take the drug at various doses. It is critical to assess the safety of the drug or device before moving on to other phases, as many of these drugs and devices have been exclusively developed using animal models. Additionally, phase 1 trials are designed to assess how the human body absorbs, metabolizes, and excretes the drug.

Phase II

• Once safety has been confirmed, researchers will move on to assessing the effectiveness of the drug. These trials are accomplished by comparing the results in patients receiving the experimental treatment with a control group of patients who receive the standard treatment or a placebo. These tests are commonly "double-blinded", meaning neither the researchers nor the patients know whether they are receiving the traditional, placebo or experimental treatment; this approach is taken to assess the impact of the so-called "placebo effect" on the experimental results.

Phase III

• Once safety and efficacy have been adequately demonstrated to the FDA, researchers can move on to the critical phase III trials. According to ClinicalTrials.gov, these tests require the recruitment of hundreds to thousands of patients and may last for several years. Phase III trials are designed to more thoroughly assess the effectiveness of the drug or device, the range of benefits and adverse reactions, as well as identify any long-term side effects. Once these trials are complete, the developer of the drug or device may apply for FDA approval and begin marketing the drug. According to "CenterWatch," 70 to 90 percent of drugs entering phase III trials are approved by the FDA.

Benefits

• Government-regulated clinical trials are designed to control the range and quality of medical devices and drugs available to the public; the FDA serves as the gatekeeper between pharmaceutical companies and American consumers. With each phase of clinical trials, there is potential for the drug or device to be deemed unsafe for use in human therapy.