FDA
FDA OKs high-dose regimen of Spinraza for spinal muscular atrophy
On March 30, 2026, FDA approved a high-dose regimen of Spinraza (nusinersen) for the treatment spinal muscular atrophy (SMA). The new regimen involves two 50-mg loading doses given 14 days apart, followed by a 28-mg maintenance dose every 4 months thereafter. Spinraza is administered intrathecally by, or under the direction of, healthcare professionals experienced in performing lumbar punctures.
Efficacy
Approval of the high dose regimen was based on the phase 2/3, randomized DEVOTE trial, which enrolled patients with SMA at 42 global sites. The study consisted of three parts: an open-label, safety evaluation cohort (Part A), a double-blind, active-controlled, randomized treatment cohort (Part B), and an open-label treatment cohort to assess patients transitioning from Spinraza low dose (12 mg) regimen to the new, high-dose regimen (Part C).
Part B included 75 treatment‑naïve patients with infantile-onset SMA (two SMN2 copies; symptom onset before 6 months of age). It was powered to assess efficacy in infantile-onset patients by evaluating the change in motor skills, as measured by Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP‑INTEND) score at day 183 in patients receiving the Spinraza high dose regimen (n=50) compared with a matched, untreated sham control group from ENDEAR (n=20; matched on baseline disease duration and baseline CHOP-INTEND score). ENDEAR is one of the two pivotal trials that supported regulatory approval of the Spinraza low-dose regimen. Part B results showed statistically significant improvement in the mean change from baseline in CHOP-INTEND at day 183 in the Spinraza high dose regimen group (15.1 point improvement) compared with the matched sham group (11.1 point worsening) (least squares mean difference, 26.19 points; 95% CI, 20.7-31.7; p <0.0001).
Safety
According to the Spinraza prescribing information, the most common adverse reactions reported in at least 10% of patients who received the Spinraza high dose regimen and occurred at least 5% more frequently than in historic matched sham control were pneumonia, COVID-19, pneumonia aspiration, and malnutrition in patients with infantile-onset SMA. The Spinraza label also includes warnings regarding renal toxicity, and thrombocytopenia and coagulation abnormalities.
Source: Biogen, Inc. (2026, March 30). FDA Approves New High Dose Regimen of Spinraza (nusinersen) for Spinal Muscular Atrophy