PTC already sells a different Duchenne drug, called Translarna, outside the United States. The FDA has not yet approved Translarna for sale here. Last year, the FDA told PTC that its application for approval of Translarna was not complete enough to be reviewed. PTC has since submitted another application for the drug to the FDA. Translarna targets only about 13 percent of Duchenne patients, whereas Emflaza can be used much more widely.