A new dosing option for spinal muscular atrophy promises higher drug concentrations and faster loading, backed by over a decade of clinical data.
On March 30, 2026, Biogen announced that the U.S. Food and Drug Administration (FDA) approved a high-dose nusinersen regimen for the treatment of spinal muscular atrophy (SMA). The regimen includes 50 mg/5 mL and 28 mg/5 mL doses. It is designed to deliver higher drug concentrations during both the loading and maintenance phases, addressing ongoing community needs.
Context
Nusinersen, marketed as Spinraza, was first approved in 2016 and transformed SMA care. It was the first disease-modifying therapy for this rare genetic disorder, which causes progressive muscle weakness and respiratory failure. More than 10 years of clinical data supported the original low-dose regimen (12 mg). The new high-dose regimen builds on that foundation.
1. The High-Dose Regimen
The high-dose regimen offers an accelerated loading phase for treatment-naïve patients: two 50 mg injections 14 days apart, followed by a 28 mg maintenance injection every four months. Patients transitioning from the low-dose regimen receive one 50 mg loading dose, then continue with 28 mg maintenance injections every four months. The regimen has already received approval in the European Union, Switzerland, and Japan.
2. Clinical Evidence from the DEVOTE Study
The FDA approval is based on the Phase 2/3 DEVOTE study. Key results from treatment-naïve symptomatic infants showed statistically significant improvements in motor function on the CHOP-INTEND scale compared to a matched sham control group from the ENDEAR study. The mean difference was 26.19 points (+15.1 vs. -11.1, p<0.0001).
Table: DEVOTE Study Key Results
| Endpoint | High-Dose Group | Control Group | Difference |
|---|---|---|---|
| CHOP-INTEND mean change | +15.1 | -11.1 | 26.19 points (p<0.0001) |
3. Safety Profile
The safety profile of the high-dose regimen was generally consistent with the low-dose regimen. Common adverse events occurring in at least 10% of patients and at least 5% more frequently than in the historical placebo group included pneumonia, COVID-19, aspiration pneumonia, and malnutrition. COVID-19 was not present in the original ENDEAR study.
What this means for international patients
For international patients seeking SMA treatment in China, the high-dose nusinersen regimen may become available through major hospitals such as Peking Union Medical College Hospital or Shanghai Children's Medical Center, pending local regulatory approval. Costs for the low-dose regimen in China typically range from $100,000 to $200,000 per year. The high-dose regimen may offer similar or slightly lower costs due to reduced injection frequency. Approval timelines in China are uncertain but may follow global approvals within one to two years.
FAQ
What is the new high-dose nusinersen regimen?
It is a dosing option with 50 mg and 28 mg doses, designed to deliver higher drug concentrations during loading and maintenance phases.
How does the high-dose regimen differ from the low-dose one?
The high-dose regimen uses larger doses and a faster loading schedule: two 50 mg injections 14 days apart, then 28 mg every four months.
Who is eligible for the high-dose regimen?
It is approved for all SMA patients, including treatment-naïve individuals and those transitioning from the low-dose regimen.
What were the key results of the DEVOTE study?
Treatment-naïve infants showed a mean improvement of 15.1 points on the CHOP-INTEND scale, compared to a decline of 11.1 points in the control group.
Is the high-dose regimen safe?
The safety profile is generally consistent with the low-dose regimen. Common adverse events include pneumonia and COVID-19.
When will it be available outside the US?
It is already approved in the EU, Switzerland, and Japan. Biogen is working with other regulatory authorities worldwide.
Next steps
For more information on SMA treatment options, including nusinersen, visit our treatment page at /treatments. Our team can help coordinate care with leading neurologists in China.
Excerpted and translated from Biogen's official website. Original article: https://investors.biogen.com/news-releases/news-release-details/fda-approves-new-high-dose-regimen-spinrazar-nusinersen-spinal
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