Biogen announced the European Commission has granted marketing authorization for a high-dose regimen of SPINRAZA (nusinersen) for treatment of 5q spinal muscular atrophy, which accounts for approximately 95% of all SMA cases. The updated regimen features two 50 mg intrathecal loading doses administered 14 days apart, followed by 28 mg maintenance injections every four months. Patients transitioning from the 12 mg dose will receive a single 50 mg dose in place of their next scheduled 12 mg injection, then continue on the 28 mg maintenance schedule. SPINRAZA has treated over 10,000 patients globally since its initial EU approval in 2017, and this new dosing option is also approved in Japan and under U.S. FDA review with a decision expected by April 3, 2026.

Approval was supported by data from the DEVOTE Phase 2/3 trial, which enrolled 145 participants across approximately 42 sites worldwide. In the pivotal cohort of treatment-naïve infants with SMA, those receiving the high-dose regimen achieved a mean 15.1-point improvement on the CHOP-INTEND scale at six months versus a –11.1-point change in a matched untreated control from the ENDEAR study (mean difference 26.19 points; p<0.0001). In an open-label cohort of older and previously treated patients transitioning from the 12 mg regimen, participants experienced a mean 1.8-point gain on the Hammersmith Functional Motor Scale–Expanded over 302 days (SD 3.99). Adverse events were consistent with SMA pathology and the known nusinersen profile; most common events occurring at ≥10% frequency and ≥5% above control included pneumonia, COVID-19, aspiration pneumonia and malnutrition, with no new safety signals identified.

Biogen underscored its commitment to rare neurological disorders, emphasizing ongoing regulatory submissions and collaborations. The SPINRAZA high-dose dossier is under review by global authorities, and the company is working to make the regimen available to the European SMA community as swiftly as possible. Biogen highlighted contributions from SMA Europe and leading investigators, including data presented by Professor Eugenio Mercuri demonstrating the regimen’s safety profile comparable to the 12 mg dose and its potential to address residual unmet needs in motor function. The updated Summary of Product Characteristics will be posted on the EMA website to guide clinicians in lumbar puncture administration by experienced specialists.