Clinical trials are conducted to collect data to determine if new drugs and devices are safe and if they work. There are several steps and stages of approval in the clinical trials process before a drug or device can be sold in the consumer market, if ever.
Drug and device testing begins with extensive laboratory testing. If the initial laboratory research is successful, the data is sent to the Food and Drug Administration (FDA) for approval to continue research and testing in humans.
After close review of the data and approval is obtained, experimental drugs and devices can begin being tested in people, and is typically conducted in four phases. Each phase is considered a separate trial and, after completion of a phase, investigators are required to submit their data for approval from the FDA before continuing to the next phase. Trials are closely monitored by physicians and regulated by the FDA.
Phase I studies assess the safety of a drug or device. This initial phase of testing, which can take several months to complete, is designed to determine the effects of the drug or device on humans including how it is absorbed, metabolized, and excreted.
Phase II studies are designed to test if the drug or device is effective. Most phase II studies are designed to have one group of study participants receive the study drug and the other group to receive a “control” whether placebo or alternative medication. Often these studies are “blinded” which means that neither the patients nor the researchers know who has received the experimental drug. This allows investigators to provide the pharmaceutical company and the FDA with comparative information about the relative safety and effectiveness of the new drug.
Phase III studies involve randomized and blind testing in several hundred to several thousand patients. This large-scale testing, which can last several years, provides the pharmaceutical company and the FDA with a more thorough understanding of the effectiveness of the drug or device, the benefits and the range of possible adverse reactions. Once Phase III is complete, a pharmaceutical company can request FDA approval for marketing the drug.
Phase IV studies, often called Post Marketing Surveillance Trials, are conducted after a drug or device has been approved for consumer sale. Pharmaceutical companies have several objectives at this stage: (1) to compare a drug with other drugs
already in the market; (2) to monitor a drug’s long-term effectiveness and impact on a patient’s quality of life; and (3) to determine the cost-effectiveness of a drug therapy relative to other traditional and new therapies.