In establishing obviousness under 35 U.S.C § 103, it is not sufficient to merely assert in a conclusory manner that certain limitations “would have been obvious or could have been predicted” while failing to address why one of ordinary skill in the art would have chosen the specific limitations claimed.
Background / Facts: The patents being asserted here in response to a generic drug ANDA submission are directed to formulations of tranexamic acid, which is used to treat heavy menstrual bleeding, or menorrhagia, in women. To combat the gastrointestinal side effects of the immediate release version used abroad, the patents describe a modified-release formulation with certain specified dissolution rates, i.e., the rate at which the salt dissolves into water. The closest prior art, the “EMA report” describing the immediate release version used in Europe, evaluates the safety and efficacy of a 500 mg tranexamic acid product comprising the excipient hydroxypropylcellulose.
Issue(s): Whether it would have been obvious to increase the amount of tranexamic acid to the claimed 650 mg and to package the drug in a modified oral dosage form based on general descriptions in the prior art listing tranexamic acid as one of many medicinal ingredients that could be used with sustained release granular preparations containing binders such as hydroxypropylcellulose.
Holding(s): No. “In this case, the cited prior art references neither set forth the limitations required by the asserted claims, nor provided any reason or motivation to combine those teachings to derive the claimed formulations with specific dissolution profiles. … First, the references disclose 500 mg tranexamic acid formulations, but no higher tablet strengths, and particularly not the claimed 650 mg formulation. The EMA report upon which [the accused infringer] relies specifically notes that an increased dose of tranexamic acid results in a concomitant dose-dependent increase in gastrointestinal side effects. … Secondly, the references do not disclose the claimed amounts of modified release polymers. The EMA report merely recites hydoxypropylcellulose, a species of hydroxyalkylcellulose, among a list of a dozen other excipients, but does not specify an amount present in the formulation of that polymer or any other inactive ingredient. … Third, [the accused infringer] did not identify any prior art references disclosing the critical dissolution limitations of the patented claims, but merely asserted in a conclusory manner that those limitations would have been obvious or could have been predicted while failing to address why one of ordinary skill in the art would choose the specific release profiles claimed.”