Clinical trials are conducted to gather data regarding the safety and effectiveness of new drug and device development. A new drug must go through several extensive steps before a drug can be brought to market for the general public.

New drugs and devices are initially tested in a laboratory on animals and human cells prior to any patient involvement. If the initial research in the lab is successful, the data is sent to the Food and Drug Administration (FDA) for approval to continue research and testing in humans.

After approval from the FDA, the experimental drug then progresses through four phases of human studies. After the completion of each phase of research, the drug must continue to be approved by the FDA prior to moving forward to the next phase.

Clinical Trial Phases

Phase I trials

Phase I trials usually deal with investigating the studied drug in a minor number of research subjects who are healthy volunteers. This phase is mainly targeted at identifying the safety, tolerability, and the general mechanism of the action of the drug in humans.

These studies are usually conducted in tightly controlled clinics where participants receive 24-hour medical attention and oversight. In some diseases in which the therapy under study is known to be too toxic for healthy subjects, phase I trials are performed in patients with diseases to test these parameters.

Phase II trials

The goal of phase II trials is to grasp additional understanding of the studied drug’s safety and efficacy. It also determines the appropriate dose to be administered to deliver the desired treatment effect while minimizing the safety risk of future research subjects. This usually requires more than 100 patients to demonstrate relevant results, although the actual number of subjects varies widely based on the disease under study. Thus, multiple clinics are utilized to recruit subjects with the disease under study to sufficiently enroll the study(ies) in a reasonable period of time.

Phase III trials

Multiple phase II studies are often required to define the appropriate patient population to study during phase III. Once the drug is deemed a potentially safe and effective candidate in phase II, it is then studied in phase III trials. This phase often exposes more than 1000 research subjects with the disease, and is usually performed at many clinics (sometimes well over 100) to enroll the trial (or trials). There is a focus on the effectiveness of the study drug in a variety of demographic and socioeconomic subjects with variants of the disease under study. A comparison is usually made with standard drugs available on the market. It is imperative that the drug is shown to be effective and safe in this phase.

Phase IV trials

In phase IV, the aim is to further characterize the safety of the drug through the identification of unknown adverse reactions and to potentially research new therapeutic indications. Companies often use this phase to gain exposure to different physicians and clinics, which aids in the marketing of their product. The entire process of a drug from lab to market may takes on average 12 to 18 years.