Sumimoto Dainippon Pharma Co./Sunovion Pharm. v. Emcure Pharmaceuticals et al.

Docket No. 2017-1798-800

April 16, 2018

Brief summary: DC determination that Sumimoto’s US 5,532,372 relating to Sunovion’s schizophrenia and bipolar depression drug LATUDA® (lurasidone) is not limited to racemic mixture affirmed.

Summary: Emcure appealed DC determination that the claims of Sumimoto’s US 5,532,372 relating to Sunovion’s schizophrenia and bipolar depression drug LATUDA® (lurasidone) “cover[s] the two three dimensional orientations” of the enantiomer “in isolation-both the one shown in the claim and its mirror image-as well as mixtures of the two in any ratio.” Based on that determination, “[t]he parties then stipulated to infringement and the entry of an injunction” with respect to Emcure’s ANDA. The FC panel opinion explains that “[l]urasidone” is “the (-)-enantiomer of an imide compound covered by the ‘372 patent”, of which examples 1(b) through 1(e) “describe methods for separating Compound 101” (the lurasidone precursor) “into its constituent enantiomers in various salt forms” including “Compound 105…which is lurasidone.” The “parties agree[d] that the specific three-dimensional structure depicted in [‘372] claim 14 is lurasidone, the (-)-enantiomer.” The question here “centered on what combination of enantiomers claim 14 encompassed.” Emcure argued claim 14 is limited “to a ‘racemic mixture of two enantiomers of which the structural formula is representative” based on “the claimed structure’s similarities to Compound No. 101, which Appellants contend is a racemic mixture, organic chemistry books suggesting that ordinary skilled artisans draw a single enantiomer as a shorthand representation for a racemic mixture, and the ‘372 patent’s prosecution history.” The DC disagreed, finding that “even if Compound 101 is a racemic mixture, its resemblance to claim 14 did not justify importing that limitation from the specification into the claim” and that “the cited extrinsic evidence and prosecution history were at best irrelevant and at worst contradictory to” Emcure’s “construction.” The courts apply “the ‘ordinary and customary meaning’ to claim terms as a person of ordinary skill in the art would have understood them at the time of the invention” (Phillips, FC 2005) unless the “patentee…acts as his own lexicographer…or…disavows the full scope of a claim term either in the specification or during prosecution” (Thorner, FC 2012; Enzo, FC 2015 (ultimate construction reviewed de novo, factual determinations based on extrinsic evidence for clear error)). The FC panel determined that “the plain language and specification demonstrate that, at a minimum, claim 14 covers what it depicts: the (-)-enantiomer” as “[b]oth parties agree that the structure shown in the claim is the (-)-enantiomer”, its scope is not limited “to a ‘racemate’ or ‘racemic mixture’”, and there is no “indication in the specification or prosecution history to the contrary” (e.g., “the specification describes it as a preferred embodiment”, although noting “the specification is inconclusive regarding whether Compound 101 is a racemic mixture”; no disavowel (SciMed, FC 2001 (described “dual lumen design” as “the present invention”)). The FC panel explained that “[t]his outcome comports with previous cases rejecting similar attempts to limit claims to racemic mixtures” citing as an example Pfizer, FC 2006 (four isomers, specification disclaimed two, claim depicted one not limited by “trans-(+/-)”, no disavowel; claim found to cover “R- and S-transiosomers as well as any mixture of the two”, and not to be limited to racemic mixture). The DC decision was therefore affirmed.

This entry was posted in Claim Construction, Generics / ANDA, Prosecution History Estoppel. Bookmark the permalink.

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