Understanding Clinical Trials
Researchers conduct clinical trials to test a new drug for treatment or prevention of disease. The process usually involves three phases of testing:
- Phase I trials usually involve a small number of patients and are
designed to evaluate safety and optimal dosing of a new drug.
- Phase II trials further test a new drug’s safety and evaluate its efficacy.
- Phase III trials involve a larger number of participants and compare
new drugs to current standard treatments. Participants are usually randomly
assigned to the group receiving standard treatment or the group receiving
the new treatment. Phase III cancer treatment trials do not include
a placebo arm (unless there is no standard treatment for that particular
cancer). Placebo arms may be included in chemoprevention trials studying
drugs that might lower cancer risk in people who do not already have
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