A new drug has to undergo thorough testing before it can be sold over the counter or with a prescription. Clinical trials are the best and way to test whether a drug or treatment is safe and effective in humans. Depending on various factors, the Food and Drug Administration (FDA) approval process may take up to nine years to complete. Typically, clinical trials are conducted in a number of phases. These phases help scientists answer various questions:
Phase I trials: Researchers test a new drug or treatment in a small group of people (15 to 50) for the first time to assess its safety, find out a safe dosage range, and identify side effects. Participants are given slowly increasing amounts of a drug up to a level of side effects that is considered acceptable. Phase I trials may include healthy participants and/or patients. When testing chemotherapy medications, cancer patients are usually participants.
Phase II trials: In this stage, the experimental drug or treatment is given to a small group, less than a hundred people, in order to determine whether it is effective and to review its safety. If the drug seems to help some of the people, and the side effects are acceptable, the drug can go on to be tested in Phase III trials
Phase III trials: The experimental drug is given to a much larger group of people (1,000-3,000) in order to confirm its effectiveness and observe side effects. The new drug or treatment is compared to the current standard treatment. Phase III trials are randomized, meaning who gets the standard and who gets the experimental treatment are selected at random. If possible, the study is also blinded, so that the patients do not know who is getting the new treatment and who is getting the standard treatment, or even double-blinded, so that the doctors also do not know. The trials are used to determine if the drug is as safe and effective as the standard treatment. A drug will be approved for sales only if it is successful in at least two phase III trials. This may take several years. After successful Phase III trials, a drug can be approved for general use by the FDA.
Phase IV trials: This stage occurs once the drug is in general use. There are side effects and adverse reactions that may only take place rarely, and may not have been seen in the Phase III trials. These trials involve a large number of patients. As more people take the new drug, rare side effects may be found. Depending on the nature of these adverse effects, there may be new warnings place on the drug, or it may even be removed from the market.
Dr. Kaplan
