There is no systematic coherent approach for evaluating the long-term safety of drugs once they have been approved for marketing by the U.S. Food and Drug Administration (FDA), according to Marie R. Griffin, M.D., M.P.H., and her colleagues at the Vanderbilt University Center for Research and Education on Therapeutics (CERT), which is supported by the Agency for Healthcare Research and Quality (HS10384).
Before drug companies can market a new drug, it must undergo extensive testing and rigorous evaluation by the FDA. However, these studies are necessarily limited as to numbers of patients and duration of followup. Therefore, a very important part of the experiment begins after the product is approved and a much larger number of patients begin to use it. During this postmarketing period, a system of voluntary reporting is relied on to detect potential problems.
In addition to voluntary reporting, the FDA may ask a manufacturer to conduct a "phase 4" or postmarketing study before or after licensure if additional information is needed to improve prescribing. Yet, companies often don't conduct these studies. As of February 2002, only 37 percent of the 2,400 postmarketing commitments for new drugs had been completed, and many had never been started.
On the other hand, manufacturers may not be the best group to evaluate postmarketing safety, according to a recent commentary by Dr. Griffin and her colleagues. Many experts agree that the major problem with the current system is the lack of an independent organization responsible for the systematic review of drugs for safety after marketing. In the last 5 years, seven CERTs and a CERTs coordinating center have been established, in part to galvanize more interest in and support for postmarketing drug studies. The CERTs program, which is administered by AHRQ, involves collaboration across all sectors—public and private, industry and government, academia and business—to improve the use of medicines and medical devices.
See "Postmarketing surveillance for drug safety: Surely we can do better," by Dr. Griffin, C. Michael Stein, M.D., and Wayne A. Ray, Ph.D., in the June 2004 Clinical Pharmacology & Therapeutics 75(6), pp. 491-494.