Trials by Types and Phases
There are many different kinds of clinical trials, including:
- trials that test new treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.
- Prevention trials, that 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, that are conducted to find better tests or procedures for diagnosing a particular disease or condition.
- Screening trials to test the best way to detect certain diseases or health conditions.
- Quality of Life trials (or Supportive Care trials), that explore and measure ways to improve comfort and the quality of life for individuals with a chronic illness.
Usually, clinical trials compare a new product or therapy to something else to see if it works as well or better to treat or prevent a disease or condition. In a blinded study, a participant may be randomly assigned to receive the test product, or an existing, approved therapy. In some studies, participants may be assigned to receive a placebo (a product with no therapeutic action that looks like the test product). Comparison with a placebo can be the fastest and surest way to demonstrate therapeutic effectiveness of new products. However, placebos are not used where a patient would be put at risk, particularly in the study of treatments for serious illnesses, by not having effective therapy. Most studies of this kind compare new products to an approved therapy. Potential participants are told before they enter a trial whether placebos are going to be used in the study.
This information sourced from :http://www.fda.gov/
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
- Phase I: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
- Phase II: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
- Phase III: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
- Phase IV: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
This information sourced from :http://www.nlm.nih.gov/