Biogen Seeks FDA Approval for a Higher Dosing Regimen of Spinraza for Spinal Muscular Atrophy

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The FDA and EMA have both accepted Biogen’s applications for a higher dose regimen of Spinraza (nusinerse) for spinal muscular atrophy (SMA). According to the company, the regimen includes a faster loading phase of two 50 mg doses administered 14 days apart, followed by a 28 mg maintenance dose every four months, compared to the current 12 mg dose. The applications were supported by data from the DEVOTE study, which found that the new regimen was able to provide efficacy and safety that is consistent with the approved regimen.¹

“We are pleased to announce that our applications for the higher dose regimen of nusinersen are now under review in the US and Europe,” said Stephanie Fradette, PharmD, head of the neuromuscular development unit, Biogen, in a press release. “This milestone reflects our steadfast commitment to advance treatment options for individuals with SMA, and we expect that this higher dose regimen will offer meaningful benefits to patients and their families. We are deeply thankful for the unwavering support of the trial participants, their families, site staff, and the SMA community without whom these advancements would not have been possible.”

The Phase II/III randomized, controlled, dose-escalating DEVOTE study evaluated the safety, tolerability, pharmacokinetics, and efficacy of the higher dosing regimen. Investigators enrolled 145 patients with multiple types of SMA into three cohorts. Part A was an open-label safety evaluation cohort, Part B was a double-blind, active control, randomized treatment cohort, and Part C was an open-label treatment cohort that evaluated the safety and tolerability of transitioning participants from 12 mg of Spinraza to the new dosing regimen.

The primary endpoint of Part B was the change from baseline on The Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders at six months. The cohort included treatment-naïve patients with infantile-onset SMA, whereas Part C included children and adults who transitioned from 12 mg to the newer regimen.¹

According to SMA News Today, the disease has an incidence rate of every 10,000 to 11,000 live births and is the second most common autosomal recessive cause of death in children in the United States. SMA News Today also stated that in the United States, Europe, and Australia, prevalence is less than 9,000 patients, while prevalence in European countries may be higher than in the United States.

There are five different forms of SMA, categorized as 0 to 4, with type 1 being the most common at 55%. SMA type 2 accounts for 30% of patients and type 3 accounts for 15% of patients. SMA types 0 and 4 are considered to be rare, accounting for less than 1% of all cases.2 There are currently three FDA-approved therapies that can improve the course of the disease.³

“Continued progress to improve upon the remarkable initial successes in SMA necessitates an innovative approach,” said Thomas Crawford, MD, co-director, Muscular Dystrophy Association Clinic at Johns Hopkins Medicine, in a press release. “Today’s announcement is a significant step forward for the community. Results from the DEVOTE study have shown us that the higher dose regimen of nusinersen can enable meaningful clinical benefits while maintaining a safety profile broadly consistent with the approved 12 mg regimen.”

Spinraza is currently approved in over 71 countries at 12 mg dose.¹

References

1. FDA and EMA Accept Applications for Higher Dose Regimen of Nusinersen in SMA. Biogen. January 23, 2025. Accessed January 24, 2025. https://investors.biogen.com/news-releases/news-release-details/fda-and-ema-accept-applications-higher-dose-regimen-nusinersen

2. Spinal Muscular Atrophy: Epidemiology and Genetics. SMA News Today. Accessed January 24, 2025. https://hcp.smanewstoday.com/spinal-muscular-atrophy-epidemiology-and-genetics/

3. Spinal Muscular Atrophy. NORD. Accessed January 24, 2025. https://rarediseases.org/rare-diseases/spinal-muscular-atrophy/