A U.S. Patent 4,927,855 was granted to Lafon for modafinil in 1990. The FDA granted modafinil orphan drug status in 1993. The formulation patent expired on 30 March 2006. The particle size patent was filed by Cephalon U.S. Patent 5,618,845, covering pharmaceutical compositions of modafinil, in 1994. That patent, granted in 1997, was reissued in 2002 as RE 37,516, which provides Cephalon with patent protection for certain preparations of the drug in the United States until 2014, which is now apparently extended to April 6, 2015 after Cephalon received a six-month patent extension from the FDA.
Some competing generic pharmaceutical manufacturers applied to the FDA to market a generic form of modafinil in 2006 (the year of patent expiry of the active ingredient). At least one withdrew its application after early opposition by Cephalon based on its new patent on particle sizes (set to expire in 2015).
Cephalon made an agreement with four major generics manufacturers Teva, Barr Pharmaceuticals, Ranbaxy Laboratories, and Watson Pharmaceuticals between 2005-2006 to delay sales of generic modafinil in the US until April 2012 by these companies in exchange for upfront and royalty payments.
Litigation arising from these agreements is still pending including an FTC suit filed in April 2008. Apotex received regulatory approval in Canada despite a suit from Cephalon's marketing partner in Canada, Shire Pharmaceuticals.
Cephalon has sued Apotex in the US to prevent it from releasing a genericized Nuvigil. Cephalon's 2011 attempt to merge with Teva was approved by the FTC under a number of conditions, including granting generic US rights to another company.
In England, Mylan Inc. received regulatory approval to sell generic Orchid-produced modafinil in January 2010; Cephalon sued to prevent sale, but lost the patent trial in November.