Biogen and Ionis have completed
the rolling submission of a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) for the approval of nusinersen to treat type 1 spinal muscular atrophy (SMA).
In August, the companies surprised the SMA community when they announced the preliminary analysis of their ENDEAR study in type 1 SMA (early onset) led them to submit a rolling NDA. While details of the data are limited, the positive results allowed the companies to stop the trial and switch all patients to an open label extension study while they focused on the NDA submission. The companies have reported
that the analysis found that infants receiving nusinersen experienced a statistically significant improvement in the achievement of motor milestones compared to those who did not receive treatment.
A submission to the European Medicines Agency (EMA) is expected in the next few weeks and other countries in the months to follow.
Studies in type 2 and 3 SMA are ongoing.
What is Spinal Muscular Atrophy?
SMA is a genetic condition that leads to a deficiency in the spinal motor neuron (SMN) protein as a result of mutations of the survival motor neuron 1 (SMN1) gene. The severity of SMA correlates with the amount of SMN protein. Generally, the muscles most affected are those near the shoulders, hips, thighs and upper back. Muscles used for breathing and swallowing may also be affected. Infants with Type I SMA produce very little SMN protein and have a life expectancy of less than two years. Children with Type II have greater amounts of SMN protein but still have a shortened lifespan and are never able to stand independently. Children with Type III have a normal lifespan but accumulate life-long physical disabilities as they grow.
Nusinersen is an antisense oligonucleotide (ASO) that is designed to alter the splicing of pre-mRNA from the SMN2
gene in order to increase production of fully functional SMN protein.