Biogen Introduces Breakthrough Salanersen Therapy for Treating Spinal Muscular Atrophy
Biogen has introduced salanersen for the treatment of spinal muscular atrophy (SMA), a rare genetic neuromuscular disorder that causes progressive muscle weakness and loss of motor function.
Salanersen is an investigational antisense oligonucleotide (ASO) designed to increase the production of survival motor neuron (SMN) protein by correcting the splicing of SMN2 pre-mRNA. The therapy is administered intrathecally and is being developed as a potential once-yearly treatment for people living with SMA.
The designation is supported by results from a Phase 1b study involving 24 children with SMA who received at least two doses of salanersen. The study showed improvements in motor function, with 12 participants achieving at least one new World Health Organization motor milestone. Among participants with elevated baseline neurofilament light chain (NfL) levels, a potential marker of ongoing neurodegeneration, NfL levels decreased by 75% at six months and remained reduced during follow-up. Salanersen was generally well tolerated, with most adverse events reported as mild to moderate.
SMA is caused by a deficiency of SMN protein resulting from a damaged or missing SMN1 gene. The condition leads to the progressive loss of motor neurons and can affect infants, children, teenagers and adults. SMA affects approximately one in 10,000 live births and remains a significant cause of disability and mortality, particularly in severe infantile forms.
The FDA’s Breakthrough Therapy Designation is intended to accelerate the development and review of medicines for serious conditions where preliminary clinical evidence indicates the potential for substantial improvement over available treatments. Biogen is advancing salanersen through a global Phase 3 programme consisting of the STELLAR-1, SOLAR and STELLAR-2 studies, evaluating the therapy across different age groups and treatment settings.
Salanersen is being evaluated at an 80 mg once-yearly dose in the Phase 3 programme. Biogen holds the global development, manufacturing and commercialisation rights for the therapy through a licence from Ionis Pharmaceuticals, which originally discovered salanersen.
