New Jersey-based Savient Pharmaceuticals has filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Barr Pharmaceuticals in response of abbreviated new drug application (ANDA) filed with the U.S. FDA seeking marketing approval for generic Oxandrin prior to expiration O.B. listed patents. Oxandrolone, active ingredient of Oxandrin tablet is an off-patent molecule disclosed in the U.S. Patent No. 3,128,283 and currently been used to promote weight gain following extensive surgery, chronic infection, or severe trauma. Orange Book currently lists five U.S. patents for Oxandrin tablet, which will run through patent protection till December 2017.