Research studies are generally divided into four phases:
Phase I trials are designed to confirm the safety of a new medication. Phase I trials generally involve a small group of healthy volunteers and typically last three to four months.
Phase II trials help to confirm whether or not a medication is effective. These studies are “randomized”. Randomization means that participants are divided into two groups—one group receives the active treatment and the other group receives a “control”. (Usually the standard treatment available).
Phase III trials are initiated once a treatment has demonstrated both safety and efficacy. Phase III trials help determine whether a medication is effective over a longer period of time. These trials are longer and larger, in terms of the number of participants. Phase III trials can provide enough data for a product to be submitted for approval by the Food and Drug Administration (FDA).
Phase IV clinical trials are conducted to obtain more information on a new medicine that has been submitted to the FDA for approval. Phase IV trials are also conducted when a company is gathering more information about a product already on the market.