In 2009 generic companies Teva Pharmaceuticals and Par Pharmaceutical made clear their intentions to file Abbreviated New Drug Applications to bring generics to market, and in April 2009 Pronova sued them from infringing the key US patents covering Lovaza, US 5,656,667 (due to expire in April 2017) US 5,502,077 (exp March 2013) and in May 2012 a district court ruled in Pronova's favor, saying that the patents were valid.[24][25][26] The generic companies appealed and in September 2013 the Federal Circuit reversed, saying that because more than one year before Pronova's predecessor company applied for a patent, it had sent samples of the fish oil used in Lovaza to a researcher for testing, and this constituted "public use" that made the patent invalid.[27][28] Generic versions of Lovaza were introduced in America in April 2014.[29]