Following positive data from competitors earlier this year, United Therapeutics Corp. rolled out impressive and unexpected phase III results of nebulized Tyvaso (treprostinil) for idiopathic pulmonary fibrosis (IPF), setting the stage for an sNDA filing with the U.S. FDA next year.  If approved for the indication, United, of Silver Spring, Md., and Research Triangle Park, N.C., could tap into what analysts say is a $4 billion-plus market.