Clinical studies use human participants to research the diagnosis, treatment and prevention of diseases or conditions. These studies are sponsored by healthcare provider organizations, pharmaceutical companies, academic medical centers and federal agencies like the National Institutes of Health. Clinical studies in the United States are tracked by U.S. National Library of Medicine.
The two types of clinical studies are:
- Observational Studies: Assess the health outcomes on groups of participants based on a research plan. Participants in observational studies are not assigned a specific intervention (such as in a clinical trial) but may receive an intervention or procedure through the course of the research.
- Clinical Trials: Give participants specific interventions, like medications, medical devices, procedures, or changes to the participants' behavior, based on the investigator’s research plan. Trials often compare intervention types for a condition or test a treatment compared to a placebo. The research team determines the specific outcomes to measure, which help determine the efficacy and safety of the intervention. Results that show the intervention significantly contributes to patient outcomes are used to advance the intervention’s approval as a treatment option.
Clinical Trial Phases
Clinical trials are often conducted through the following research phases, as defined by the Food and Drug Administration (FDA):
- Phase I – treatment’s safety tested on a small group of individuals
- Phase II – larger study group to test treatment efficacy and continue to evaluate its safety
- Phase III – confirms treatment’s effectiveness, monitors side effects and compares to other treatment options on a large group of individuals
- Phase IV – post-approval studies for additional risk, benefit and best use information