14th April 2026: UK Medicines and Healthcare products Regulatory Agency (MHRA) Approves New High Dose Regimen of SPINRAZA® (nusinersen) for Spinal Muscular Atrophy

The new high dose, delivered via lumber puncture, will have a more rapid loading phase than the current dose people in the UK receive. There will be two 50 mg loading doses administered 14 days apart. There will then be 28 mg maintenance dose injections every four months.

If agreed, individuals transitioning from the 12 mg dose will receive one 50 mg dose in place of their next 12 mg dose. This will then be followed by 28 mg maintenance doses every four months.

The authorisation is based on data from the three-part, Phase 2/3 DEVOTE study and its ongoing long-term extension. Scroll down for more information about the study and its results.

Biogen community statement – MHRA approval of nusinersen HD- UK ENG 2026 >

More about nusinersen >

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30th March 2026: FDA Approves New High Dose Regimen of SPINRAZA® (nusinersen) for Spinal Muscular Atrophy

High Dose SPINRAZA will be available in the United States in the coming weeks and is also approved in the European Union, Switzerland and Japan

Biogen’s Press Release >

12th January 2026: European Commission (EC) has granted marketing authorization for a high dose regimen of nusinersen (SPINRAZA^®)

The new high dose regimen has a more rapid loading phase:

• two 50 mg loading doses administered 14 days apart
• 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.

• Japan has also recently approved this high dose regimen of nusinersen.
• It is currently 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 advance the high dose regimen as an additional dosing option for people living with SMA..

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The DEVOTE Study

This phase 2/3 study, which enrolled 145 patients across all ages and SMA types, consisted of 3 parts:

• An open-label safety evaluation cohort (part A)
• A pivotal, double-blind, active control randomised treatment cohort (part B) and
• An open-label treatment cohort (part C)

In Part B, 75 treatment-naïve children with infantile-onset SMA received either:

• the higher dose regimen of nusinersen – which comprises a more rapid loading regimen, two 50 mg doses 14 days apart and a higher maintenance regimen of 28 mg every four months – or
• the currently approved nusinersen 12 mg regimen (comprising four loading doses followed by maintenance doses every four months).

In Part C, 38 children and adults transitioned to the high dose regimen after a median of 3.9 years on the approved 12 mg regimen.

The main findings of this study were:

• Significant improvements in motor function were observed in the higher dose group, as measured by the CHOP-INTEND test, from the start to six months. These improvements were compared to a similar untreated control group from the Phase 3 ENDEAR study.
• Results favoured the higher dose regimen relative to the untreated control group from the ENDEAR study across secondary endpoints. They also showed a positive trend towards the higher dose regimen over the currently approved 12 mg regimen among key biomarker and efficacy measures;
• The higher dose regimen was generally well tolerated with reported side-effects similar to those seen in SMA and nusinersen’s known safety profile.

17th November 2025: See Biogen’s Press Release for more detailed results from the DEVOTE study >

4th Feb 2026: Biogen announces DEVOTE results are published in the journal NATURE >