SMA is characterized by lower motor neuron loss and progressive muscle weakness and is caused by a genetic defect in the SMN1 gene that codes SMN, a protein necessary for survival of motor neurons.
The company received orphan drug designation from the US Food and Drug Administration (FDA) for SMA in October 2014.
Currently, there are between 25,000 – 50,000 SMA patients in the US, Europe and Japan combined.
AveXis chief executive officer Sean Nolan said: "Receiving Orphan Drug designation for our investigational medicine in the EU is an important regulatory milestone in the advancement of our development program for SMA.
"We look forward to continuing dialogue with global regulators as we work to develop this treatment for patients suffering from SMA around the world."
AveXis’ most advanced product candidate, ChariSMA, is in a fully-enrolled Phase I trial for the treatment of SMA.