Overview of clinical trials

Introduction

New medical tests and treatments aren’t offered to the public as soon as they’re discovered. They need to be appropriately studied to determine their safety and effectiveness. Clinical trials are formal research studies to evaluate a medical treatment. Clinical trials can study many things, including:

• New drugs not yet approved by the U.S. Food and Drug Administration (FDA)
• New uses of drugs already approved by the FDA
• New ways to administer drugs, such as in pill form
• New tests to find and track disease.

According to the National Institutes of Health (NIH), a clinical trial is “a research study in which one or more human subjects are prospectively assigned to one or more interventions to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes.”

If the answers to the following four questions are all yes, a study meets the NIH’s definition of a clinical trial:

1. Does the study involve human participants?
2. Are the participants prospectively assigned to an intervention?
3. Is the study designed to evaluate the effect of the intervention on the participants?
4. Is the effect being evaluated a health-related biomedical or behavioral outcome?

Types of clinical trials

Clinical trials typically advance through several phases when testing a new treatment:

• Phase I trials test an experimental treatment on a very small group of people to assess its safety and side effects and to determine appropriate drug dosages.
• Phase II trials enroll a larger group and focus on determining effectiveness of the treatment for individuals with a certain disease or condition. They also continue to study safety, including short-term side effects.
• Phase III trials obtain additional information about safety and effectiveness, studying different populations and dosages, often using the drug in combination with other drugs. If the FDA decides that the Phase III results are positive, it will approve the treatment for clinical use.

Participating in a clinical trial

In the United States, over 10,000 clinical trials are held each year. Clinical trials can offer patients access to investigational therapies intended to provide better ways to treat their disease, as well as the opportunity to contribute to medical research. However, they also have associated risks and uncertainties. It’s important to thoroughly understand the purpose, the potential side effects, and possible outcomes of a clinical trial when considering enrollment. If you are interested in participating in a clinical trial, speak with your your doctor who can help you determine which clinical trials may be a good match for you.

Clinician perspectives