Clinical Trial Phases
Cancer Treatment Clinical Trial Phases
The testing of new treatments in clinical trials is divided into four phases:
Phase I trials help researchers determine the most appropriate dosage and to identify any side effects that may be associated with the new treatment. This phase also helps determine the best way to deliver the new treatment – for example if a drug should be given by injection or by mouth. Phase I trials typically involve fewer than 100 participants.
Phase II trials test the treatment in patients who have the targeted medical condition in order to begin determining its effectiveness. Researchers continue to track the drug’s safety and side effects. Phase II trials involve more patients, but are still very limited in size.
Phase III trials compare the new treatment to one or more standard therapies currently in use among patients. The new treatment is sometimes combined with established therapies to determine if the combination is more effective than standard therapy alone. Safety and side effects continue to be tracked as the study expands to include hundreds or even thousands of patients.
Phase IV trials can begin once the treatment is approved for general use to continue to monitor its safety and effectiveness and to give researchers and physicians additional information about how best to employ the new treatment.