FDA rejects BioMarin’s Duchenne drug

BioMarin has been informed by the FDA that its drug Kyndrisa (drisapersen) cannot be approved to treat the rare disease Duchenne muscular dystrophy.

Investors have been expecting the news since November, when FDA experts first informed the company that data on the drug's effectiveness in treating the muscle-wasting disease was weak. The regulator has now issued a Complete Response Letter saying the 'standard of substantial evidence of effectiveness' has not yet been met.

BioMarin says it will work with the FDA to determine what can be done – the regulator could call for entirely new trials to be conducted.

However BioMarin remains hopeful that Europe's regulator may still approve the drug with the existing data, with a preliminary ruling expected in April or May, and a final decision in the autumn.

Investors anticipating the bad news has seen BioMarin's share price lose around 25% of its value in the last three months, so much so that the final announcement barely caused the price to dip.

The setback for BioMarin is good news for its competitors – Sarepta Therapeutics and PTC Therapeutics have rival products for the condition.

PTC's drug Translarna won conditional European approval last year, while Sarepta's drug eteplirsen will be reviewed by an FDA advisory panel next week.

Even though Translarna has conditional marketing approval, the UK's NICE rejected it in preliminary guidance in October, questioning both its clinical- and cost-effectiveness.