A clinical trial is a research study that explores whether a medical strategy, investigational treatment or device is safe and effective for humans. For most clinical research of a potential new treatment, there are four general phases.
- Phase 1 tests safety in humans by giving the investigational treatment or drug to healthy volunteers.
- Phase 2 tests safety and effectiveness in patients living with the disease being studied.
- Phase 3 tests safety and confirms effectiveness in patients with the disease and studies a larger group of people than in a Phase 2 trial.
- Upon completion of Phase 3, regulatory agencies – for example, the U.S. Food & Drug Administration (FDA) or the European Medicines Agency (EMA) – determine whether the treatment can be prescribed by physicians to patients.
- Phase 4 tests the drug’s effect in various populations and any side effects associated with long-term use after the drug is approved.
Individuals choose whether or not to participate in clinical trials for various reasons, including:
- Gaining early access to potential treatments being studied for safety and effectiveness
- Receiving additional expert medical care
- Contributing to medical research
- Potentially helping future generations of individuals with the same condition
- Understanding the risks and potential benefits of an investigational therapy
- Considering the requirements of the study protocol
Talk to your doctor if you are interested in participating in a clinical trial and visit the Frequently Asked Questions section for more information about clinical trials.