US regulators give go-ahead for muscle wasting treatment costing $3mn

Shares in biotech Sarepta Therapeutics soared as much as 40 per cent on Thursday after US regulators approved its request to widen access for a $3.2mn-per-patient gene therapy that treats a rare muscle wasting disease.

The US Food and Drug Administration on Thursday gave Sarepta Therapeutics the green light to roll out Elevidys, its gene therapy for Duchenne muscular dystrophy, which was already available to children aged four and five years old, to all patients aged four and over.

An estimated 15,000 children and young adults in the US are affected by Duchenne, which stems from a genetic defect that causes the body to erode its own muscle fibres, leaving many children reliant on a wheelchair by their early teenage years and with an average life expectancy of just 22 years. The condition particularly impacts young boys, with one in every 3,500 live male births affected.

The FDA granted a full approval for Sarepta to offer the gene therapy Elevidys to children aged four and over who are still able to walk, and an accelerated approval for patients aged four and over using a wheelchair. Since last year, Sarepta has been allowed to offer the treatment to mobile patients between ages four and five via the FDA’s fast-track approval process for breakthrough medicines targeting serious conditions.

Doug Ingram, Sarepta’s chief executive, told the Financial Times that the FDA decision was “something that Duchenne families have been waiting for for many years”, adding that it was “an enormous milestone for gene therapy more generally”. Swiss drugmaker Roche owns the global rights to the medicine and is applying for a similar label expansion in Europe.

Sarepta’s shares rose as much as 42 per cent in after-hours trading, giving the biotech a market value of more than $16bn, before falling slightly.

Before the arrival of Sarepta’s gene therapy, the main option for Duchenne patients was the use of steroids to slow the progression of the disease. Finding more effective treatments has proven difficult. Pfizer announced earlier this month that its own Duchenne gene therapy had failed to improve motor function in a late-stage trial in 99 boys between ages four and seven.

The FDA decision will open up a huge potential market for Sarepta, which is projected to generate peak annual revenues of $3.3bn in 2027, up from $1.1bn last year, driven by sales of Elevidys.

However, Elevidys is one of the most expensive medicines in the world, and its cost effectiveness has been criticised.

David Rind, chief medical officer of the Institute for Clinical and Economic Review, an influential non-profit that assesses drug prices, wrote last month that it came with “an enormous price tag” despite failing its primary endpoint as measured by a motor function test.

Sarepta’s Ingram said “any objective, scientifically minded person would realise that this treatment is bringing a better life to patients and they deserve access to it”. Elevidys did succeed on other tests, including improving patients’ speed in walking 10 metres.

Sarepta is one of the bigger biotech stocks. As such, analysts have pegged it as a likely acquisition target due to the success of Elevidys. Ingram said the company wanted to be “masters of our destiny”, but that it “will be thoughtful in the event that anything was broached with us”.