Drug safety discontinuations in the United Kingdom, the United States, and Spain from 1974 through 1993: a regulatory perspective.

The objective of the present study was to compare the number of new chemical entities (NCEs) and new biologicals entities (NBEs) approved for marketing during the period 1974 through 1993 in the United Kingdom, the United States, and Spain that were subsequently discontinued (removed from the market, withdrawn, or whose license was allowed to lapse) while a question of safety existed. Of the products approved during the two decades of the study period, a total of 29 drugs were subsequently discontinued for safety reasons in at least one of the three countries (United Kingdom: 20 safety discontinuations; United States: 10; and Spain: 16). These represent 3% to 4% of all drugs introduced in these countries, an increase compared to the period from 1964 through 1983, when approximately 2% of all NCEs were discontinued for safety reasons. The therapeutic classes most commonly associated with safety discontinuations were the nonsteroidal anti-inflammatory drugs (nine drugs), vasodilators (four drugs), and antidepressants (three drugs). U.S. companies or their foreign subsidiaries were involved as originators (patent-holders and/or developers) of approximately 40% of the drugs discontinued for safety reasons.