U-M follows the 2014 NIH Clinical Trial Definition: A research study  in which one or more human subjects are prospectively assigned to one or more interventions (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes. (The NIH definition with footnotes included is available here.)

Please note that how legal or regulatory requirements apply to your clinical trial may depend upon other definitions.  For help with ClinicalTrials.gov requirements, consult  the UMMS Office of Regulatory Affairs. For assistance conducting clinical trials at UMHS, consult the Clinical Trials Support Office.

Clinical trials are used to determine whether new biomedical or behavioral interventions are safe, efficacious, and effective. Clinical trials are often characterized in phases: 

  • PHASE 0: Officially named at the FDA as an exploratory investigational new drug study and also known as a “microdosing” study. Exploratory trials to establish whether the agent behaves in humans as was expected from preclinical animal studies, to gather preliminary data on pharmacodynamics or pharmacokinetics, to select promising lead candidates, or to explore biodistribution characteristics. Phase 0 studies do not replace formal Phase I drug safety testing and do not offer any possibility of patient benefit. Intended to speed drug development as part of the FDA Critical Path Initiative by quickly weeding out ineffective drugs early in the development process. (No therapeutic or diagnostic intent.)
  • PHASE I: Initial studies to determine the metabolism and pharmacologic actions of the agent in humans, the side effects associated with increasing doses, and to gain early evidence of effectiveness; may include healthy participants and/or patients.
  • PHASE I/II (Device – Pilot): Some trials combine Phase I and Phase II, and test both efficacy and toxicity (safety, dosage levels, and response to new treatment). 
  • PHASE II:  Controlled clinical studies conducted to evaluate the effectiveness of the agent for a particular indication or indications in patients with the disease or condition under study and to determine the common short-term side effects and risks.
  • PHASE II/III:  Some trials combine Phase II and Phase III, and test for both efficacy and overall benefit-risk relationship.  The new treatment is compared to a standard treatment regimen.
  • PHASE III (Device – Pivotal):  Expanded controlled and uncontrolled trials after preliminary evidence suggesting effectiveness of the agent/test article has been obtained and are intended to gather additional information to evaluate the overall benefit-risk relationship and provide an adequate basis for physician labeling. Compares new agent/test article against commonly used agents/test articles.
  • PHASE IV:  Post-marketing studies to delineate additional information including the agent’s risks, benefits, comparative effectiveness, and optimal use. These studies are designed to monitor the effectiveness of the approved intervention in the general population and to collect information about any adverse effects associated with widespread use.