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FAQ - Frequently Asked Questions

What is a clinical trial?
A clinical trial refers to any experiment in which one or more human subjects receive a drug or device for the purpose of determining the safety and/or efficacy of a diagnostic, therapeutic, or preventive use in human subjects.

What are the phases of a clinical trial?
Phase I - Phase I trials include the initial introduction on an investigational new drug into humans. These studies are typically conducted with healthy volunteers, sometimes where the drug is intended for use in patients with a particular disease, however such patients may participate as subjects. Phase I trials are designed to determine the metabolic and pharmacological actions of the drug in humans, the side-effects associated with increasing doses, (to establish a safe dose range) and if possible, to gain early evidence of effectiveness; they are typically closely monitored. The ultimate goal of Phase I trials is to obtain sufficient information about the drug's pharmokinetics and pharmacological effects to permit the design of well-controlled, sufficiently valid Phase II studies. Other examples of Phase I studies include studies of drug metabolism, structure-activity relationships, and mechanisms of actions in humans, as well as studies in which investigational drugs are used as research tools to explore biological phenomena or disease processes. The total number of subjects involved in Phase I investigations is generally in the range of 20-80.

Phase II - Phase II trials include controlled clinical studies conducted to evaluate the drug's effectiveness for a particular indication in patients with the disease or condition under study, and to determine the common short-term side effects and risks associated with the drug. These studies are typically well-controlled, closely monitored, and conducted with a relatively small number of patients, usually involving no more than several hundred subjects.

Phase III - Phase III trials involve the administration of a new drug to a larger number of patients in different clinical settings to determine the safety, effectiveness, and appropriate dosage. They are performed after preliminary evidence of effectiveness has been obtained and are intended to gather necessary additional information about effectiveness and safety for evaluating the overall benefit-risk relationship of the drug, and to provide an adequate basis for physician labeling. In Phase III studies, the drug is used the way it would be administered when marketed. When these studies are completed and the sponsor believes that the drug is safe and effective under specific conditions, the sponsor applies to FDA for approval to market the drug. Phase III trials usually involve several hundred to several thousand patients.

Phase IV - Concurrent with marketing approval, FDA may seek agreement from the sponsor to conduct certain postmarketing (Phase IV) studies to delineate additional information about the drug's risks, benefits and optimal use. These studies could include, but would not be limited to, studying different dosages or schedules or administration than were used in Phase II studies, use of the drug in other patient populations or other stages of the disease, or use of the drug over a longer period of time.

What is an Investigational New Drug?
A drug or device permitted by FDA to be tested in humans, but not yet determined to be safe and effective for a particular use in the general population, and not yet licensed for marketing.1

Who is the Principal Investigator and how is that person different from an Investigator?
The Principal Investigators is the individual with primary responsibility for the conduct of a research project. In a clinical trial, the Investigator is an individual who actually conducts an investigation. Any interventions (e.g. drugs) involved in the study are administered to subjects under the immediate direction of the Investigator. A Principal Investigator and an Investigator may be the same individual.*

You should be able to answer the following questions once you have met and discussed a clinical trial with the physician:

  • What is the purpose of the study?
  • What is required of me?
  • Will I receive treatment when participating in a study?
  • What are the direct benefits to me?
  • Will my participation benefit others?
  • Will my privacy be protected?
  • Will anyone know I am participating in a study?
  • Are there risks? If so, what?
  • Who is sponsoring the study?
  • Will I have to pay for anything? If so, what?
  • What if I am hurt as a result of the study?
  • Will I be paid for participating?
  • Who can I call if I have questions?

*The OPRR 1993 Protecting Human Research Subjects Institutional Review Board Guidelines, pp5-6, 5-7