Biogen on Wednesday said that an experimental, higher dose of its spinal muscular atrophy drug Spinraza met the primary endpoint of a clinical trial comparing it with a historical control group.
It now plans to seek approval from the FDA for the experimental regimen, which is more than twice the current dose.
In the trial, the drug significantly improved motor function in infants compared to the untreated control group from one of the studies that led to the drug’s initial approval in 2016 (p<0.0001), Biogen said in a statement announcing the results. Motor function was measured using a scale called CHOP-INTEND at six months.
It’s not clear, however, exactly how the experimental dose compared with the approved one. Biogen said that the data “trended in favor” of the higher dose, but didn’t say in its announcement whether it actually hit the secondary endpoints. It also said the percentage of serious adverse events was lower in the higher-dose regimen compared to the 12 mg group (60% vs. 72%).
The company said detailed data will be presented at a future medical conference.
Spinraza has a list price of $142,000 for a 12 mg dose/5 ml vial. Biogen declined to comment on how the higher dose of the therapy would be priced. But if the price per milligram is kept the same, the higher-dose regimen would cost more than twice the approved regimen in the first year and every year thereafter.
The pivotal cohort of the Phase 2/3 DEVOTE study included 75 children with infantile-onset spinal muscular atrophy, or SMA. The children had not received treatment before, and were randomized 2-to-1 to receive either the higher-dose regimen or the approved regimen.
The higher-dose regimen consists of two 50 mg doses 14 days apart, and a higher maintenance regimen of 28 mg every 4 months. The currently approved regimen uses 12 mg doses with four loading doses and then maintenance doses every four months.