PTC Therapeutics, Inc. achieved a $20 million milestone payment from Roche under its license and collaboration agreement. The milestone payment was triggered by the first commercial sale of Evrysdi (risdiplam) in the U.S. Evrysdi was approved by the FDA on August 7, for the treatment of spinal muscular atrophy (SMA) in adults and children 2 months of age and older.   Evrysdi is a survival motor neuron 2 (SMN2)-directed RNA splicing modifier designed to treat SMA caused by mutations in chromoso...