Biogen has announced that the European Medicines Agency (EMA) and US Food and Drug Administration (FDA) have started reviewing a higher dose regimen of its spinal muscular atrophy (SMA) treatment Spinraza (nusinersen).
The antisense oligonucleotide is already approved in more than 71 countries at a dose of 12mg to treat infants, children and adults with the neuromuscular disease.
The company is now seeking approval for a “more rapid” loading regimen of two 50mg doses two weeks apart, compared to the current four loading doses, and a higher maintenance regimen of 28mg every four months.
Affecting approximately one in every 10,000 babies worldwide, SMA is a rare, progressive genetic disorder characterised by insufficient levels of the survival motor neuron (SMN) protein. Symptoms vary, but can include muscle weakness, problems with breathing and swallowing, and tremors.
Biogen’s Spinraza is administered directly into the central nervous system and targets the underlying cause of motor neuron loss by continuously increasing the amount of full-length SMN protein produced in the body.
The company’s applications for its higher dose regimen were supported by positive results from the phase 2/3 DEVOTE study, which enrolled 145 SMA patients across approximately 42 global sites.
Results from part B of the trial were announced in September and demonstrated a statistically significant improvement in motor function at six months in patients with infantile-onset SMA who received higher dose Spinraza compared to those in an untreated control group from the phase 3 ENDEAR study.
The higher dose regimen also showed benefits over the currently approved 12mg regimen on key biomarker and efficacy measures, and was generally well tolerated.
Stephanie Fradette, head of Biogen’s neuromuscular development unit, said: “We are pleased to announce that our applications for the higher dose regimen of [Spinraza] are now under review in the US and Europe… we expect that this higher dose regimen will offer meaningful benefits to patients and their families.”
Thomas Crawford, co-director of the Muscular Dystrophy Association Clinic at Johns Hopkins Medicine, added: “Continued progress to improve upon the remarkable initial successes in SMA necessitates an innovative approach. [This] announcement is a significant step forward for the community.”