Biogen’s Higher Dose Spinraza Shows Enhanced Efficacy in Treating Spinal Muscular Atrophy

Clinical Trial Success:

Biogen's Phase II/III DEVOTE study demonstrated that a higher dose regimen of Spinraza (nusinersen) significantly improved motor function in infants with spinal muscular atrophy (SMA) compared to a prespecified, untreated control group from the ENDEAR study.

Dosing Regimen:

The higher dose regimen includes two 50 mg doses given 14 days apart, followed by a maintenance dose of 28 mg every four months, differing from the approved 12 mg regimen.

Efficacy Outcomes:

Infants receiving the higher dose showed a statistically significant improvement in motor function, as measured by CHOP-INTEND scores, with an adjusted average difference of 26.19 compared to the sham group.
The higher dose also led to a more rapid reduction in neurofilament light chain (NfL), a marker of neurodegeneration, with a 94% reduction from baseline to Day 183.

Safety Profile:

The higher dose was generally well tolerated, with adverse events consistent with SMA and Spinraza’s known safety profile. Serious adverse events were less frequent in the higher dose group (60%) compared to the 12 mg group (72%).

Regulatory Plans:

Biogen plans to submit regulatory applications for approval of the higher dose regimen of nusinersen around the world.

Market Context:

Spinraza generated $1.74 billion in sales for Biogen in 2023, with sales expected to decrease to $1.13 billion by 2030 due to competition and pricing pressure.