The investigative process for new drugs

In summary, there are preclinical and clinical developmental periods during the study of new drugs. The latter is composed of three phases of study under an IND. The purpose of phase I is to show the initial safety of the drug. Efficacy should be demonstrated in phase II. Long-term studies in a large number of patients in phase III are designed to demonstrate the long-term safety and continued efficacy of the drug. Following review and acceptance that the data generated during these two developmental periods and submitted by the sponsor under an NDA demonstrate the safety and efficacy of the drug, the drug may be approved for marketing. If so, there will be continued evaluation of the drug during postmarketing surveillance. The phases of study that are required to demonstrate that a new drug is safe and efficacious are straightforward and clearly defined. The methods that are best used to satisfy these requirements are less clear and more open to interpretation by both sponsors and Agency reviewers. Guidelines for the testing of new drugs are extremely helpful in this regard, but will never (and probably never should) take the place of enlightened individual judgment on the part of investigators, sponsors, and FDA reviewers.