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  • Types and Phases of Clinical Trials

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    After extensive research on a scientific question is deemed promising, clinical trials are conducted to test the findings in human beings. Clinical trials proceed with volunteers who have given informed consent and are interested in taking part.

    Types of Trials

    Clinical trials may include treatment, prevention, screening, diagnostic and quality of life trials.

    1. Treatment trials test new treatment technology such as a cancer drug or a new combination of treatment approaches. These new treatment technologies, that could prove promising in treating a condition, usually cannot be received outside of the clinical trial.
    2. Prevention trials study new methods of preventing the development of certain diseases or stopping the resurfacing of a disease. These new approaches may include vaccines, medicines, vitamins or supplements, but this is not always the case.
    3. Quality of life trials research new processes to improve the experiences of patients and make their treatments more comfortable and less upsetting. For example, a cancer patient who is dealing with the negative effects of chemotherapy may benefit from a quality of life trial.

    Clinical Trial Phases

    Generally, clinical trials proceed through three phases.

    1. Phase I trials test a new drug or medical approach and are at the beginning of the human research stage. If the trial involves a new drug, phase I will identify the best way in which that drug should be administered, how often and the strength of the dosage. The trial facilitators will increase the dose until the patient experiences side effects; thus, the highest appropriate dose is approved for continued testing. The side effects will be carefully observed and examined. Phase I trials generally involve a small amount of participants.
    2. Phase II trials scrutinize the safety and efficacy of a drug or medical approach. They closely identify the new approach's effect on the body. Phase II trials are generally more focused, only treating a specified type of cancer for example.
    3. Phase III trials are comparison studies. These trials compare and contrast the new research with the standard technology already being used. Participants are randomly divided into treatment groups. Some are treated with the new medical approach, while others receive the standard treatment. Phase III studies may be national or international and include hundreds or thousands of participants. A study reaches Phase III when it has shown significant promise in the first two phases.

    Taking part in a clinical trial is a voluntary decision, and a choice you can reverse at any time during the trial. All clinical trials are reviewed and approved by Lifespan's Institutional Review Board.

    More about participating in a research study

    For general information about clinical trials please visit the National Cancer Institute.