Lurasidone – USA

On Apr. 16, 2018, Court of appeal for the federal circuit affirmed New Jersey district court’s claim construction in LATUDA® & found patent infringed by ANDA filers in Hatch-Waxman litigation.

This Hatch-Waxman appeal required federal circuit to construe the scope of a claim depicting a compound’s chemical structure. Although the compound can exist in two different three-dimensional orientations that are mirror images of each other, only one is portrayed in the claim. The district court construed the claim to cover the two three-dimensional orientations in isolation—both the one shown in the claim and its mirror image—as well as mixtures of the two in any ratio.

Sumitomo Dainippon Pharma Co. and Sunovion Pharmaceuticals Inc. own U.S. Patent No. 5,532,372. The ’372 patent relates generally to “novel imide compounds and their acid addition salts” that are useful as antipsychotic agents. Lurasidone, the (–)-enantiomer of an imide compound covered by the ’372 patent, is the active ingredient in Sunovion’s schizophrenia and bipolar depression drug LATUDA®. After Emcure Pharmaceuticals Ltd., Heritage Pharma Labs Inc., InvaGen Pharmaceuticals, Inc., Teva Pharmaceuticals USA, Inc., and Teva Pharmaceutical Industries, Ltd. (collectively, “Appellants”) filed ANDA seeking approval to market generic versions of LATUDA®, Sumitomo and Sunovion sued the Appellants for infringing claim 14 of the ’372 patent.

The claim construction question for the district court centered on what combination of enantiomers claim 14 encompassed. Appellants sought to limit claim 14 to “a racemic mixture of two enantiomers of which the structural formula is representative.” For support, Appellants relied on the claimed structure’s similarities to Compound No. 101, which Appellants contend is a racemic mixture, organic chemistry textbooks suggesting that ordinarily skilled artisans draw a single enantiomer as a shorthand representation for a racemic mixture, and the ’372 patent’s prosecution history. The district court rejected Appellants’ narrow construction, which would have excluded the specific enantiomer depicted in claim 14. The court adopted Sunovion’s proposal to construe claim 14 as covering “lurasidone, lurasidone’s enantiomer, as well as mixtures of these enantiomers.” Following the district court’s claim construction order, Appellants stipulated to infringement of claim 14 and the entry of permanent injunctions. Appellants then filed this appeal.

On appeal, federal circuit said that the plain claim language and specification demonstrate that, at a minimum, claim 14 covers what it depicts: the (–)-enantiomer. Of equal importance is the lack of anything in the claim language limiting its scope to a “racemate” or “racemic mixture.” Absent some indication in the specification or prosecution history to the contrary, it follows that the plain and ordinary meaning of claim 14 covers at least the specific enantiomer depicted in the claim itself. Federal circuit further said that Appellants’ claim construction arguments conflict with Pfizer and other precedent because they seek to import limitations from the specification into the claim. Even if Compound No. 101 is a racemic mixture, the specification neither defines claim 14’s structure as Compound No. 101 nor disclaims scope in a way that confines claim 14 to a racemic mixture. Claim 14 does not refer to Compound No. 101, and nothing in the specification links the two structures together.

Federal circuit further said that, Appellants’ organic chemistry textbooks and expert testimony do not compel a different result. Extrinsic evidence is, in general, “less significant than the intrinsic record in determining ‘the legally operative meaning of claim language.’” Phillips, 415 F.3d at 1317 (quoting C.R. Bard, Inc. v. U.S. Surgical Corp., 388 F.3d 858, 862 (Fed. Cir. 2004)). This is particularly so here, where the intrinsic record demonstrates that claim 14’s structure covers at least the (–)-enantiomer. Federal circuit thus did not see clear error in the district court’s rejection of the organic chemistry textbooks as irrelevant or contradictory to Appellants’ construction.

Thus, finally federal circuit held that district court did not err in construing claim 14 to cover the (–)-enantiomer. The judgment of the district court therefore affirmed.