Food and Drug Administration (FDA, the American drug regulator) say an application to licence eteplirsen would be premature

Tuesday 12 November 2013

Sarepta Therapeutics announced today that the Food and Drug Administration (FDA, the American drug regulator) in the USA considered the company's plans to file an application for eteplirsen to be licensed as premature. 

 The FDA is basing their decision partly on the results of the large phase 3 clinical trial carried out by GlaxoSmithKline and Prosensa that showed that drisapersen - a drug similar to eteplirsen - failed to show that boys who received the drug could walk further than those that received placebo (an inactive form of the potential drug). They also state that there are new findings regarding the natural progression of Duchenne muscular dystrophy, which suggests that the stabilisation observed during Sarepta's phase 2b extension trial might not be caused by the drug but could be due to the natural course of the condition. The trial involved only a small number of boys and a larger study will be needed to demonstrate that eteplirsen is an effective treatment.

The FDA also expressed doubts that dystrophin can be used as a biomarker in clinical trials. Biomarkers are biological substances found in blood, urine or other parts of the body that can be used as an indicator in clinical trials to see how well the body responds to a potential treatment. In the FDA's opinion, there is not sufficient knowledge about the levels of dystrophin that are needed in the muscle to assume that its levels can show whether a treatment will be effective.

Sarepta Therapeutics is committed to continuing with a phase 3 trial which they plan to start early next year. The trial will involve about 120 boys. As soon as we receive more details we will update this page to keep you informed.

Dr Marita Pohlschmidt, Director of research at Muscular Dystrophy Campaign, said:

   “The refusal of the FDA to grant Sarepta’s request for an opportunity to apply for a license for eteplirsen will be upsetting news for many families. The decision reflects concerns that the results of Sarepta’s Phase 2b clinical trial were based on a very small group of boys and that a Phase 3 trial is necessary to demonstrate that eteplirsen is an effective treatment for Duchenne muscular dystrophy. We welcome Sarepta’s commitment to pushing ahead with a Phase 3 trial, due to start early next year.”

Chris Garabedian, president and chief executive officer of Sarepta Therapeutics said:

We are very disappointed with the FDA's decision to reconsider their openness to a potential NDA filing based on our current data and the resultant impact this change may have on our efforts to achieve an earlier approval of eteplirsen. We strongly believe in the potential of eteplirsen to address a serious unmet medical need in DMD and we are committed to its development. Our team at Sarepta recognizes the urgency of families who are seeking new treatments, and we will continue to work with the FDA on an acceptable confirmatory study design and, in parallel, seek to address their concerns regarding a potential NDA filing based on our current dataset.