Understanding Clinical Trials – Part 3: What are the Phases of Clinical Trials?

Phases of Clinical TrialsThe goal of clinical trials is to determine if new treatments, drugs and care-delivery processes are safe and effective. Discovery and data collected from clinical research studies impacts patient care, here and now, while also informing future generations with the hope of achieving better outcomes. But clinical studies do not happen overnight, and in fact, some take years to yield enough information to answer specific questions they are designed to answer.

Clinical trials take place in “phases,” and each phase helps researchers answer specific questions. Learn more about the different phases of clinical trials below:

Phase I:

These trials are used to test brand new drugs, devices or procedures to find out how safe they are, including safest dose, and identify possible side effects. They usually involve 20 to 80 people.

Phase II:

These trials are used to further evaluate the effectiveness of a drug, device or procedure. The researchers keep track of any medical benefits, as well as side effects. They usually involve 100 to 300 people. At the end of Phase II trials, the U.S. Food and Drug Administration (FDA) and trial sponsors determine how Phase III trials will be conducted.

Phase III:

These trials compare a new treatment or procedure to current treatments to figure out which works better. Safety and level of effectiveness continued to be monitored, as well as side effects. They usually involve 1,000 to 8,000 people.

Phase IV:

Once a drug or procedure is approved by the FDA and made available to the public, researchers continue to study its safety to figure out the best use of the new treatment. Information is gathered on the drug’s long-term effectiveness in various populations, as well as adverse side effects associated with long-term use. In the video below, Dr. Donald Harvey walks through the different phases of cancer-specific clinical trials.

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