Comparison of Drug Approvals in Europe Versus the United States: An Analysis of Discrepancies Between Drug Products Reviewed by EMA and FDA

Background: Regulators from the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) do not always agree on interpretation of data for a drug's safety and efficacy.

Methods and results: The authors compared all new molecular entities approved or rejected in a 5-year period from 2007 to 2011, identified where FDA and EMA reviews resulted in different regulatory decisions, and explored potential mechanisms for the discrepancies. Thirteen entities were associated with different regulatory decisions, and 2 drugs were withdrawn from their respective markets in 2010: one from the US (Mylotarg; gemtuzumab ozogamicin) and the other in Europe (Thelin; sitaxentan sodium).

Conclusions: There are relatively few cases where FDA and EMA substantively differ with regard to product approvals and market withdrawals. It is likely that the scientific and cultural differences between FDA and EMA will continue to diminish over time, because these two agencies increasingly work together as pharmaceutical product development increasingly becomes a global endeavor.