Biogen Reports Positive Results for a Higher Dose of Spinraza

A higher dose of Spinraza (nusinersen) reduced a marker of the neurodegeneration that is a feature of spinal muscular dystrophy (SMA), the drug’s maker, Biogen, said in a news release today.

The higher dose met is primary endpoint in a study that compared a treated group to a prespecified matched group of patients treated with a sham treatment in a different trial.

Patients treated with the higher dose were also compared directly with those treated with the lower one but no difference was seen between the two groups in that comparison. The news release said the analyses were not “adequately powered to detect significant differences.”

Secondary analyses, however, consistently favored the higher dose group, according to the news release.

The investigational higher dose consists of a more rapid loading regimen, two 50-milligram (mg) doses 14 days apart and a higher maintenance regimen of 28-mg doses give every four months.

The lower dose regimen, which has been approved by the FDA, consists of 12 mg doses, starting with four loading doses and then a maintenance dose given every four months.

Spinraza is an antisense oligonucleotide (ASO) therapy. Short sequences of nucleotides bind to specific regions of a gene and modify its expression. The FDA approved Spinraza in late 2015. Today’s Biogen news release says that more than 14,000 individuals have been treated with the drug.

According to a presentation made to the New York state Medicaid drug utilization board last year, the wholesale acquisition cost price of the first year of treatment with Spinraza using the 12-mg dose is $765,000 and the price for a year of treatment of the maintenance doses, $382,500.

According to the company news release, the higher dose regimen led to a 94% decrease in plasma neurofilament light chain at Day 183 compared with a 30% reduction in the sham group. Plasma neurofilament light chain levels are marker for the neurodegeneration that underlies Spinal Muscular Atrophy. Thomas Crawford, M.D., co-director of the Muscular Dystrophy Association Clinic at Johns Hopkins Medicine in Baltimore, was quoted in the press release as saying that the higher dose version of Spinraza had benefits across the various spinal muscular atrophy phenotypes.