CAMBRIDGE, Mass. — Biogen Inc. (Nasdaq: BIIB) today announced the European Commission (EC) has granted marketing authorization for a high dose regimen of SPINRAZA® (nusinersen) which is comprised of 50 mg/5 mL and 28 mg/5 mL doses for the treatment of 5q spinal muscular atrophy (SMA). 5q SMA is the most common form of the disease and represents approximately 95% of all SMA cases.2 The SPINRAZA European Union marketing authorization has been updated to include the high dose regimen. The new high dose regimen comprises a more rapid loading phase, two 50 mg loading doses administered 14 days apart and 28 mg maintenance dose injections every four months thereafter. Individuals transitioning from the 12 mg dose will receive one 50 mg dose in place of their next 12 mg dose, followed by 28 mg maintenance doses every four months thereafter. SPINRAZA is for intrathecal use by lumbar puncture by health care professionals experienced in performing lumbar punctures.
“Since its approval in the European Union in 2017, SPINRAZA has helped set a new standard in patient care and treated more than then 10,000 infants, children, teens and adults worldwide,” Priya Singhal, M.D., M.P.H., Executive Vice President and Head of Development at Biogen. “We are proud to introduce the high dose regimen of SPINRAZA, which we have developed to address the evolving needs of individuals living with SMA, and are deeply committed to bringing it to the European SMA community as quickly as possible. We are grateful for all of the contributions of the SMA community who made today’s approval possible.”
The EC approval is based on data from the three-part, Phase 2/3 DEVOTE study and its ongoing long-term extension. Results from the pivotal cohort of the study showed treatment-naïve, symptomatic infants who received the high dose regimen of SPINRAZA experienced statistically significant improvements in motor function as measured by the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND), when compared to a prespecified matched sham (untreated) group from the ENDEAR study* (mean difference: 26.19 points; +15.1 vs. -11.1, p<0.0001). Improvements in motor function were also observed in the open label cohort of individuals across a broad range of ages and SMA types who transitioned from the low dose regimen. These participants experienced a mean improvement on the Hammersmith Functional Motor Scale – Expanded of 1.8 points [SD 3.99] from baseline to Day 302.1
“The DEVOTE results provide encouraging evidence that this new dosing option could deliver meaningful treatment outcomes with a safety profile generally consistent with the 12 mg dosing regimen,” said Eugenio Mercuri, M.D., Ph.D., Professor of Pediatric Neurology at the Catholic University, Rome, Italy. “I have witnessed the remarkable strides that have been made in treating SMA, but it is clear challenges remain. The European Commission approval of the high dose regimen of SPINRAZA is an important step toward addressing those challenges and advancing how we care for people living with SMA.”
Throughout the study, high dose regimen was generally well tolerated, with reported adverse events consistent with SMA and the known safety profile of nusinersen. No new safety concerns were observed with continued use of high dose nusinersen in the long-term-extension study. In the DEVOTE study, the most common adverse events that occurred in at least 10% of participants treated with the high dose regimen and occurred at least 5% more frequently than the matched sham group were pneumonia, COVID-19, pneumonia aspiration, and malnutrition.1
Special warnings and precautions for use of nusinersen include adverse reactions as a part of the lumbar puncture procedure, low platelet counts and blood clotting abnormalities, renal toxicity and hydrocephalus (excessive buildup of cerebrospinal fluid in the brain).3
“As a community, we welcome advances that expand options for people living with SMA and reinforce continued innovation in SMA care,” said Nicole Gusset, CEO of SMA Europe. “This approval highlights the importance of sustained research and investment, contributing to a wider range of possibilities that may enable more tailored approaches to SMA care over time.”
The updated Summary of Product Characteristics will be available on the European Medicines Agency website at www.ema.europa.eu.
The high dose regimen of SPINRAZA is also approved in Japan and is under review with the U.S. Food and Drug Administration (FDA) with a decision expected by April 3, 2026. Biogen is working with regulatory authorities around the world to progress this additional dosing option for people living with SMA.
*ENDEAR is one of the two pivotal studies that formed the basis of regulatory approvals for SPINRAZA 12 mg.
About the DEVOTE Study1
DEVOTE was a Phase 2/3 randomized, controlled, dose-escalating study designed to evaluate the safety, tolerability, pharmacokinetics and efficacy of SPINRAZA when administered at a higher dose (50/28 mg). The study enrolled 145 participants across ages and SMA types at approximately 42 sites around the world. DEVOTE included an open-label safety evaluation cohort (Part A), a double-blind, active control randomized treatment cohort (Part B), followed by an open-label treatment cohort (Part C) to assess the safety and tolerability of transitioning participants from the currently approved dose of SPINRAZA 12 mg to the higher dose regimen being tested in the study.
Part B was comprised of a pivotal cohort in treatment-naïve patients with infantile-onset SMA (n=75), and a supportive cohort in treatment-naïve patients with later-onset SMA (n=24). The primary endpoint of Part B measured the change from baseline on CHOP-INTEND at six months, comparing the high dose regimen of nusinersen to a matched, untreated sham control group from the Phase 3 ENDEAR study. ENDEAR is one of the two pivotal studies that formed the basis of regulatory approval for SPINRAZA 12 mg.
Part C was an open-label evaluation of the higher dose regimen in children and adults who transitioned from SPINRAZA 12 mg to the 50/28 mg regimen (n=40).
About SPINRAZA
The high dose regimen of SPINRAZA (nusinersen) which is comprised of 50 mg/5 mL and 28 mg/5mL injections are approved in the European Union and Japan to treat infants, children and adults with spinal muscular atrophy (SMA). The high dose regimen of nusinersen is currently under review with the U.S. Food and Drug Administration (FDA) with a decision expected by April 3, 2026. SPINRAZA 12 mg/5 mL injection is approved for SMA in more than 71 countries.4
The low dose regimen of SPINRAZA has shown efficacy across ages and SMA types with a well-established safety profile based on data in patients treated up to 10 years,5,6 combined with unsurpassed real-world experience. The most common adverse events observed in clinical studies were respiratory infection, fever, constipation, headache, vomiting and back pain. Laboratory tests can monitor for renal toxicity and coagulation abnormalities, including acute severe low platelet counts, which have been observed after administration of some ASOs.
Biogen licensed the global rights to develop, manufacture and commercialize SPINRAZA from Ionis Pharmaceuticals, Inc. (Nasdaq: IONS). For more information, visit your respective country’s product website. For the U.S., please click here for Important Safety Information and full Prescribing Information .
About Biogen
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References
- Crawford TO, et al. Exploring Higher Doses of Nusinersen in Spinal Muscular Atrophy: Final Results From Parts B and C of the 3-Part DEVOTE Study. Presented at: World Muscle Society (WMS) Congress; 2024; Prague, Czechia.
- Farrar MA, Kiernan MC. The Genetics of Spinal Muscular Atrophy: Progress and Challenges. Neurotherapeutics; 2015; 12:290–302.
- European Medicines Agency. SPINRAZA Summary of Product Characteristics. Available at: https://www.ema.europa.eu/en/documents/product-information/spinraza-epar-product-information_en.pdf. Last accessed: December 2025.
- Based on commercial patients, early access patients, and clinical trial participants through December 31, 2022.
- Core Data sheet, Version 13, October 2021. SPINRAZA. Biogen Inc, Cambridge, MA.
- Finkel RS, et al. Final Safety and Efficacy Data From the SHINE Study in Participants With Infantile-Onset and Later-Onset SMA. Presented at: Cure SMA Conference; 2024; Austin, Texas.
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