Clinical Trials

Defining Clinical Trials

A clinical trial is a research study done to evaluate new potential treatments in people. During a clinical trial, information is collected to determine if a study drug is safe and effective, as well as to evaluate the risks and benefits of the study drug. For more information about clinical trials, please visit ClinicalTrials.gov.

Research and Development for Clinical Trials

Research and development occurs in several stages before clinical trials commence in people. Pre-clinical testing is conducted for each investigational product to evaluate the safety, efficacy, best practices for administration, and many other properties before entering human clinical trials. Once adequate pre-clinical testing has been completed, applications are submitted to the relevant regulatory authorities so they can evaluate the investigational drug for safety to assure that human clinical trial participants will not be subjected to an unreasonable risk.

Clinical Trial Phases

Human clinical trials are conducted in four phases:

Phase 1: A study drug is tested in people, often in volunteers without disease, for the first time to evaluate its safety and best practices for administering the drug.

Phase 2: The study drug is tested to determine a safe dose or range of doses, to further evaluate its safety, and to begin testing in subjects with the disease of interest to determine if the drug has the intended or predicted effects.

Phase 3: The study drug is tested, often in larger trials of longer duration, to confirm its effectiveness and to further evaluate safety. Phase 3 trials often compare the study drug to commonly-used treatments (if any) or to placebo treatment, if it is scientifically and ethically appropriate to do so.

Phase 4: Post-marketing studies are performed after regulatory agency approval occurs. These studies are designed to collect additional information including the drug’s risks, benefits and optimal use in a broader patient population often over extended periods of time. An example of a Phase 4 study would be a registry to collect medical information on a disease population, whether they are taking the approved drug or not.

Regulatory Review

When Phase 1–3 clinical trials are completed, a Marketing Application (e.g., a New Drug Application [NDA] for the US FDA, or a Marketing Authorisation Application [MAA] for the European authorities) is submitted to regulatory agencies. The Marketing Application contains all data gathered about the safety and effectiveness of the study drug from the pre-clinical studies and clinical trials that have been performed. The Marketing Application also contains information about the chemistry, toxicology, pharmacology and manufacturing processes of the product. The regulatory agency reviews the data and, if approved, the new treatment can be marketed and distributed to the public through prescription by a qualified physician.