FDA Clinical Trials – What They Are, How They Work

In order for a new medication or medical device to get approval from the Food and Drug Administration, it must undergo clinical trials – and those trials must demonstrate the new product's safety and efficacy before it is allowed to be marketed and sold.

A clinical trial is defined by the National Institutes of Health as a research study that determines “whether a medical strategy, treatment or device is safe and effective for humans.” Using the scientific method, researchers begin by looking for answers to specific questions – in this case, how to treat the symptoms of a specific health condition or discovering ways to diagnose or screen for certain diseases.

In some cases, a clinical trial builds on previous research centered around similar diseases and their treatments. A clinical trial follows set procedures, known as protocols. These consist of step-by-step plans on what researchers will actually be doing and how they will carry out these tasks, in addition to detailed explanations of each step of the process and why they are required.

The first step in any clinical trial is to develop and test new strategies under laboratory conditions by studying chemical reactions in test tubes and petri dishes. If those preliminary studies produce the desired results, the next step is animal testing, which demonstrates how the drug or treatment works under biological conditions. Rodents such as mice and rats are generally used during this stage due to their biological similarities to primates.

Despite the similarities between primates and rodents, however, success in such animal studies does not mean that the treatment will successfully treat humans. The process is not over until human trials have been completed. However, before an experimental treatment can be used on human subjects, the company must file an Investigational New Drug (IND) application. The IND application must be accompanied by a complete report of all pertinent data, including the drug's ingredients and mechanism of action as well as its effects on animal subjects.

Human trials are conducted on volunteers who meet certain criteria, which can vary depending on the nature and purpose of the study. For example, trials for a new treatment for a specific type of cancer requires subjects who are suffering from that particular form of the disease. A drug for treating prostate issues would necessitate having male subjects who may or may not suffer from said disorders, depending on whether the treatment was preventive or meant to mitigate the symptoms. Alternatively, a study may focus on genetic conditions that affect certain populations.

Human clinical trials consist of four stages, or phases. During Phase I, researchers administer the treatment or medication to a small group of subjects in order to determine whether or not it works and to evaluate its safety as well as to establish a baseline for dosage. If this is successful, the trials are opened to a group of approximately 100 volunteers. This is Phase II, during which the treatment is compared to other existing drugs or devices currently used to treat the diseases in question.

Once the treatment has been proven safe and effective, it is administered to a larger population during Phase III in order to confirm the results obtained in Phase II. During the Phase III trial, researchers use what is known as a “control group.” Subjects in the control group are given a placebo, or inert substance, instead of the actual treatment. Ideally, this part of the study is “double blind,” meaning that neither the subjects nor the research team know who is being given the placebo until this phase of the trial is concluded.

The final step, Phase IV, does not begin until the drug or treatment has been approved for the market. Also known as “post-market studies,” Phase IV trials follow patients who receive the treatment, evaluating the long-term efficacy and safety of the product and its effect on the general population as well as interactions and side effects that may not have been apparent during clinical studies.