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What is a Clinical Trial?

A clinical trial (also clinical research) is a research study in human volunteers to answer specific health questions. Carefully conducted clinical trials are the fastest and safest way to find treatments that work in people and ways to improve health. Interventional trials determine whether experimental treatments or new ways of using known therapies are safe and effective under controlled environments. Observational trials address health issues in large groups of people or populations in natural settings.

Why participate in a clinical trial?

Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research.

Why are there clinical trials?

A clinical trial is one of the final stages of a long and careful research process. Studies are done with patients to find out whether promising approaches to prevention, diagnosis, and treatment are safe and effective.

What are the different types of clinical trials?

  • Treatment trials test experimental treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.
  • Prevention trials look for better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vitamins, vaccines, minerals, or lifestyle changes.
  • Diagnostic trials are conducted to find better tests or procedures for diagnosing a particular disease or condition.
  • Screening trials test the best way to detect certain diseases or health conditions.
  • Quality of Life trials (or Supportive Care trials) explore ways to improve comfort and the quality of life for individuals with a chronic illness.

What are the phases of clinical trials?

Clinical trials are conducted in phases. The trials at each phase have a different purpose and help scientists answer different questions:

Phase I trials - researchers test an experimental drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.

Phase II trials - the experimental study drug or treatment is given to a larger group of people (100-300) to see if it is effective and to further evaluate its safety.

Phase III trials - the experimental study drug or treatment is given to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the experimental drug or treatment to be used safely.

Phase IV trials - post marketing studies delineate additional information including the drug's risks, benefits, and optimal use.