[Patients organizations and new drug approval in the US. Eteplirsen and Duchenne muscular dystrophy case].

INTRODUCTION: In 2016 the US Food and Drug Administration (FDA) granted the marketing authorization for eteplirsen for Duchenne muscular dystrophy. This has been a very controversial decision since it happened after a negative assessment from both the Advisory Committee and the technical FDA evaluation team. The FDA's Center for Drug Evaluation and Research (CDER) director was who ultimately approved the product, while the FDA Commissioner did not overrule that decision.

AIM: To report about the most relevant events regarding the approval of eteplirsen by the US FDA.

DEVELOPMENT: All relevant facts that occurred during the clinical development and evaluation phase following 'accelerated approval' procedure of eteplirsen are discussed in detail. The technical FDA evaluation team reasons supporting that the drug has not proven clinical benefit, the attitude of patient advocacy groups and the post-approval FDA requirements to the marketing authorization holder are discussed. Finally, we reflect on what is the situation Spanish patients face once eteplirsen is on the US market.

CONCLUSIONS: This is a unique case in the history of drug authorizations in western countries, that shows the difficulties that current regulations on accelerated approval of new medicines could have when interpreting scarce and low quality clinical development data, when dealing with rare diseases with no available therapies.