FDA asks for more data on Sarepta’s muscular dystrophy drug

There has been much speculation about whether the US regulator will finally approve Sarepta Therapeutics’ eteplirsen for Duchenne muscular dystrophy, causing the biotech’s share price to yo-yo.

Massachusetts-based Sarepta said late last month that the US Food and Drug Administration would delay a decision on eteplirsen past its legal deadline of May 26.

But little else was known about what had caused the regulator to hold off amid intense patient pressure to approve the drug for the rare, inherited, muscle-wasting disease.

Now Sarepta has shed more light on the matter – in a statement last night it said that the FDA has requested more data on levels of the key dystrophin protein from biopsies already obtained from the ongoing PROMOVI study of eteplirsen.

The company plans to submit western blot data from 13 patient biopsy samples, at baseline and week 48, to the FDA over the coming weeks in order to secure a prompt decision.

Advisers to the FDA have already recommended against approving the drug – even though hundreds of boys affected by the disease and their families attended the meeting of the Central Nervous System Advisory Group in April.

The advisers were not convinced by Sarepta’s clinical evidence – but the committee’s 7-3 vote, with three absentions, against approval is non-binding.

The FDA does not have to follow recommendations from its committees – so there is still a chance that eteplirsen will be approved.

If eteplirsen is approved, Sarepta will have a clear run at the US market after rivals fell by the wayside.

BioMarin last week decided to end development of its Kyndrisa (drisapersen) after the CHMP regulatory committee said it intended to reject the drug. The FDA also rejected Kyndrisa in January.

Development of three follow-on products, in phase 2 trials, will also cease.

The FDA has also rejected PTC Therapeutics’ filing for its DMD rival Translarna (ataluren), although this has been approved in Europe and recommended for funding by the UK’s cost-effectiveness body, NICE.

Sarepta’s share price jumped 3% in after-hours trading to $16 following the announcement yesterday.

Related stories:

FDA advisers reject Sarepta’s eteplirsen for DMD

FDA rejects BioMarin’s Duchenne drug

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