New drugs: evidence relating to their therapeutic value after introduction to the market.

Background: Drug approval is based on three criteria: quality, efficacy, and safety. We investigated the types of study design and statistical methods employed to demonstrate safety and efficacy of proprietary medicinal products (PMPs) that were approved for use in the European Union through the centralized procedure.

Methods: We retrospectively analyzed the European Public Assessment Reports of PMPs that the European Medicinal Agency approved, either initially or for extended indications, in 2009 and 2010.

Results: Data were analyzed for 39 PMPs: 64% of these were new active substances, and 36% were approved for extended indications. 46% of the PMPs had been studied in an active-control trial. In only 28%, superiority of the new PMPs compared to active control had been tested. 46% of the approvals included testing of a patient-relevant primary endpoint. The median size of population used to demonstrate safety was 1700 persons.

Conclusion: The centralized procedure does not require comparative information from active-control trials. Accordingly, as our descriptive analysis revealed, this information is often not available at the time of market introduction. Pivotal studies only rarely clearly demonstrate an added therapeutic value of a new PMP compared to existing alternatives.