United Therapeutics sues North Carolina competitor for patent infringement

United Therapeutics Corp. has filed a lawsuit against Morrisville, North Carolina-based Liquidia Technologies Inc. for allegedly violating a patent for one of its pulmonary arterial hypertension drugs. The suit, filed Thursday in U.S. District Court for Delaware, alleges that Liquidia infringed on the Silver Spring biotech’s two patents for Tyvaso, an inhalation system that uses active ingredient treprostinil, when it filed a new drug application with the Food and Drug Administration for an inhaled,…