Research with people is conducted according to strict scientific and ethical principles. Researchers must follow the study’s protocol (an action plan, which acts like a “recipe” for conducting the trial). An Institutional Review Board at each participating hospital or study site must approve the protocol before the study can start. The board, which includes consumers, clergy, and health professionals, ensures that the study will be conducted fairly and that participants are not likely to be harmed. The Institutional Review Board also conducts ongoing review of the study.
Researchers explain the study thoroughly to patients, through the informed consent process. During informed consent, researchers provide the key facts about a clinical trial (including the study’s purpose, tests and other procedures, and possible risks and benefits) and answer the patient’s questions to help him/her decide whether to participate. The informed consent process continues throughout the study. For example, if new information on benefits, risks, or side effects becomes available during the study, researchers inform the participants immediately. Participants can leave a study at any time.
Phases of Clinical Trials
Clinical trials are conducted in four phases:
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Phase I studies test a new drug or treatment for the first time in people (20 - 80) to evaluate its safety, determine a safe dosage range, and identify side effects.
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Phase II studies focus on learning whether the new treatment has an anticancer effect (e.g., shrinking
the tumor or improving blood test results). These studies involve 100 - 300 people.
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Phase III studies compare the results of people taking the new treatment with results of people taking the standard treatment; placebos (sugar pills) are never used in cancer clinical trials. Participants are assigned by chance (randomized) to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, no one knows which treatment is best. Phase III studies include 1,000 - 3,000 people.
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Phase IV studies collect more information on a drug or treatment after its approval in the United States, including on the best way to use it and its risks and benefits.