Biogen’s successor to Spinraza (nusinersen) has shown benefit in spinal muscular atrophy (SMA) patients who had suboptimal clinical status despite prior administration of gene therapy.
In the Phase Ib trial (NCT05575011), patients treated with salanersen, an investigational novel antisense oligonucleotide (ASO), experienced a slowing of neurodegeneration and functional improvement, including achievement of new World Health Organization (WHO) motor milestones. This was in patients who had previously been treated with Novartis’ Zolgensma (onasemnogene abeparvovec-xioi).
Go deeper with GlobalData
Discover B2B Marketing That Performs
Combine business intelligence and editorial excellence to reach engaged professionals across 36 leading media platforms.
Leveraging the same mechanism of action as Spinraza – increasing production of functional SMN proteins – but designed to achieve greater potency, Biogen believes that salanersen has the potential to achieve high efficacy while enabling once yearly dosing. Meanwhile, Spinraza is dosed once every four months.
In patients who received salanersen 40mg and 80mg and had elevated baseline concentrations of neurofilament light chain (NfL), meaningful reductions of 75% in NfL levels were observed at six months; these reductions were sustained throughout the follow-up period.
Notably, 12 of the 24 patients achieved at least one new WHO motor milestone, and all participants maintained the motor milestones documented at their baseline.
Salanersen was generally well-tolerated at both doses in the study, with most adverse events (AEs) having been mild to moderate in severity.
US Tariffs are shifting - will you react or anticipate?
Don’t let policy changes catch you off guard. Stay proactive with real-time data and expert analysis.
By GlobalDataDr Thomas Crawford, co-director, Muscular Dystrophy Association Clinic at Johns Hopkins Medicine, said: “SMA has benefitted from extraordinary therapeutic progress, but across the treatment landscape, there remains room for improvement. There is growing scientific and clinical enthusiasm about the advances that salanersen offers. These additional Phase I data add confidence in the emerging salanersen clinical profile.”
The data, presented at the 2026 Muscular Dystrophy Association (MDA) Clinical & Scientific Conference, also suggested a minimum once-yearly dosing of the candidate. Biogen also unveiled three Phase III trial designs for salanersen at the conference.
STELLAR-1 will be an open-label study to evaluate the effects of salanersen in young (under six weeks old), treatment-naïve and clinically presymptomatic infants with a genetic diagnosis of SMA.
STELLAR-2 will be a randomised, double-blind, sham-controlled study to evaluate salanersen when initiated approximately six months after Zolgensma in infants with SMA who received presymptomatic treatment with the gene therapy at six weeks of age or younger.
Finally, the open-label SOLAR study will evaluate salanersen in teens and older adults (aged 15–60 years) with SMA who are either treatment-naïve or previously treated with Roche’s Evrysdi (risdiplam).
Biogen licensed the global development, manufacturing and commercialisation rights for salanersen from Ionis Pharmaceuticals in 2022.
SMA is a rare, genetic and neuromuscular disease that affects patients of all ages. It is characterised by a loss of motor neurons in the spinal cord and lower brain stem, resulting in progressive muscle atrophy and weakness.
According to GlobalData analysis, the SMA market across the seven major markets (7MM: France, Germany, Italy, Japan, Spain, the UK and the US) is set to grow from $2.7bn in 2023 to $3bn in 2033.
GlobalData is the parent company of Clinical Trials Arena.
