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Under the microscope: Zolgensma

This month: Zolgensma


What is Zolgensma?
It a one-off gene therapy treatment for spinal muscular atrophy – a rare degenerative disorder that afflicts infants. The condition can lead to death within two years.

So it’s just a one-time treatment?
The drug is administered intravenously or intrathecally. An AAV9 viral vector delivers the SMN1 transgene to cell nuclei where the transgene begins encoding SMN protein, addressing the root cause of the disease. Since motor neurons do not divide, only one dose is needed.

That’s great news.
Steady on – it is also the most expensive drug in the world at $2.1m for a single dose.

That’s a lot of money.
It certainly is. Novartis, who brought the drug to market, has stressed the expense of developing such innovative drugs. In this case, Novartis did not develop Zolgensma, but bought AveXis, the company that did, for £8.7bn.

Are there any alternatives?
Biogen’s Spinraza, which is already on the market, but must continue to be injected into the spines of patients for their whole lives, at a price of $750,000 for the first year and $375,000 a year after that.

So that can end up being even more expensive.
Yes, that’s what Novartis claims, pointed out that the high cost of its drug is still 50% less than the +$4m for 10 years of treatment of Spinraza.

Where is Zolgensma approved?
In May, it was authorisation to treat spinal muscular atrophy in children under 24 months in the US. AveXis filed for European approval in 2018 and NICE has started to consider its assessment process.

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