The US Food and Drug Administration (FDA) has rejected Biogen’s high-dose Spinraza (nusinersen) for the treatment of spinal muscular atrophy (SMA).
The agency chose to decline the antisense oligonucleotide’s (ASO) approval due to insufficient technical information listed under the chemistry, manufacturing and controls (CMC) section of its supplemental new drug application (sNDA).
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Despite the FDA’s identification of CMC-related issues with Spinraza’s application, Biogen noted that the complete response letter (CRL) did not mention any issues with the clinical data submitted in a 23 September statement.
Though the therapy’s high-dose rejection will be a setback for Biogen, the company has stated that the missing CMC information is “readily available”, meaning the big pharma will likely resubmit the amended application to the FDA shortly.
Biogen’s head of development Priya Singhal said: “While this outcome was unexpected, we remain committed to bringing the high-dose regimen to people living with SMA.”
While Spinraza’s rejection has grabbed headlines, the drug is not the first to be hit with a CRL due to CMC issues this week.
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By GlobalDataOn 23 September, the FDA rejected Scholar Rock’s SMA drug apitegromab after issues with Catalent’s fill-finish facility – the primary manufacturing site for the drug – were uncovered by the agency.
It was a similar story for biotechs Ultragenyx, Capricor and Rocket Pharmaceuticals, which have all faced CMC-related application rejections in the past few months.
Spinraza faces tough market
Upon its approval in 2016, low-dose Spinraza (12mg/5mL) became the first drug to receive the FDA green light for SMA, offering patients with the neuromuscular disorder a disease-modifying therapy (DMT) for the first time in history. This milestone came soon after Biogen licensed the drug’s global rights from its creator, Ionis Pharmaceuticals.
Though Spinraza saw a steep rise to fame upon its market release – becoming a blockbuster asset for Biogen by 2018 – sales of the drug have been on a steady decline since its $2bn peak in 2019.
This drop in sales was primarily driven by competition from newly approved DMTs, including Novartis’ gene therapy Zolgensma (onasemnogene abeparvovec) and Roche-owned Genentech’s small molecule Evrysdi (risdiplam). These drugs were approved in 2019 and 2020, respectively.
Competition from orally administered Evrysdi has been a particular headache for Biogen, as the drug removes the necessity for painful lumbar injections, giving it a dosing edge over Spinraza. This has led GlobalData’s analysts to forecast a rosy sales outlook for Evrysdi, with the drug predicted to make nearly $3bn for Roche in 2031.
Though one-time gene therapy Zolgensma abolishes the need for daily dosing as required by Evrysdi, it poses less of a threat to Spinraza’s market share due to its exorbitant price tag of $2.1m per patient. This made the most expensive drug in history upon its approval.
Moving forward, analysts at GlobalData, parent company of Pharmaceutical Technology, forecast that, though Spinraza will maintain its blockbuster status, its sales will continue to diminish up to 2031, where the drug is predicted to make nearly 50% less than it did in 2019.
