The FDA decision on Risdiplam, proposed for the treatment of spinal muscular atrophy is expected on August 24, 2020.Initially developed by PTC Therapeutics (PTCT) in partnership with the SMA Foundation, the worldwide license to Risdiplam is now with Roche.Spinal muscular atrophy or SMA is a genetic disease caused by a defect in SMN1 gene that leads to deficiency of a motor neuron protein called SMN, which is necessary for normal motor neuron function.Risdiplam, an orally administered liquid, is designed to durably increase and sustain SMN protein levels both throughout the central nervous system and in peripheral tissues of the body.If approved, Risdiplam will have to compete with Biogen’s Spinraza and Novartis’s gene therapy Zolgensma.Cantor Fitzgerald expects Risdiplam to achieve peak sales of $3.2 billion while the potential peak sales estimated by RBC Capital Markets are $2.6 billion.PTCT closed Friday’s (Jul.24, 2020) trading at $47.15, down 1.40%.