Spinraza, which also showed a favorable safety profile in the study, is an antisense oligonucleotide (ASO) that is designed to change the splicing of SMN2, a gene that is nearly similar to SMN1, in order to increase production of fully functional SMN protein.
The 15-month study included a total of 126 non-ambulatory patients with later-onset SMA (consistent with Type 2). The participants had signs and symptoms at greater than 6 months and an age of 2 to 12 years at screening.
From baseline to 15 months of treatment, patients who received Spinraza achieved a mean improvement of 4.0 points as measured by the Hammersmith Functional Motor Scale Expanded (HFMSE), while patients who were not on treatment declined by a mean of 1.9 points.
A change of three points or greater in the HFMSE has earlier been identified as clinically meaningful.
Biogen exercised its option to global rights to Spinraza in August this year. The company is preparing for a potential US launch of Spinraza, which was developed by Ionis, as early as the end of 2016 or in the first quarter of next year.
Biogen executive vice president, head of research and development Michael Ehlers said: “These results, along with our successful trial in infantile-onset SMA, reinforce the potential of Spinraza to benefit a broad range of SMA patients.
“We will make regulators around the globe aware of this data and will continue working closely with them to bring Spinraza to families affected by SMA as quickly as possible.”
Spinraza has been granted orphan drug status in the US and Europe. It has also received special status, including fast track designation and priority review in the US, and accelerated assessment in Europe.
Image: Exterior view of Ionis Pharmaceuticals building. Photo: courtesy of Ionis Pharmaceuticals.