Over the past years the benefits and risks associated with pharmaceutical agents have received increasing attention from the medical community. Some doubts have arisen concerning the current approach of drug approval based on clinical trials. In most cases these studies include relatively small numbers of patients, which can lead to an incomplete safety profile assessment of these drugs at the time of approval. In addition, safety profile and effectiveness may change when these drugs are used in a wider, less carefully selected population than patients included in clinical trials.

This phenomenon has been discussed in detail by Giezen and colleagues [1] in a recent publication. In this study of 174 biological products (antibodies, hormones, enzymes) approved from January 1995 through June 2007, including 136 agents approved in the US, 105 approved in the European Union, and 67 approved in both regions, the authors found 82 safety-related regulatory actions. The probability of a biological agent having a first safety-related regulatory action was 14% at 3 years and 29% at 10 years after approval.