PTC Therapeutics, Inc. announced that the U.S. Food and Drug Administration (FDA) has granted priority review of a supplemental new drug application (sNDA) for Evrysdi® (risdiplam) to expand the indication to include pre-symptomatic infants under 2 months old with spinal muscular atrophy (SMA). If approved, Evrysdi would be the first medicine administered at-home for pre-symptomatic babies with SMA. Included in the sNDA submission was interim data from the RAINBOWFISH study, which showed 80 % of pre-symptomatic infants with SMA treated with Evrysdi for at least 12 months achieved motor milestones such as sitting without support, rolling, crawling, standing unaided, and walking independently.

Evrysdi is designed to treat SMA by increasing and sustaining the production of the SMN protein, which is found throughout the body and is critical for maintaining healthy motor neurons and movement. Evrysdi was based on PTC's splicing platform. Evrysdi is marketed by Roche and in the United States by Genentech, a member of the Roche Group.

Roche leads the clinical development of Evrysdi as part of a collaboration with the SMA Foundation and PTC Therapeutics.