Sumitomo Dainippon Pharma Co., Ltd. v. Emcure Pharmaceuticals Ltd., No. 17-1798 (Fed. Cir. 2018)Annotate this Case
Stereochemistry is the study of a molecule’s three-dimensional structure. Stereoisomers are molecules with the same chemical formula and structure but different three-dimensional configurations. Enantiomers, non-superimposable mirror images of one another, often have identical physical properties, such as density and boiling point, but can exhibit different pharmacological properties in the human body. Sumitomo’s 372 patent relates generally to “novel imide compounds and their acid addition salts” that are useful as antipsychotic agents. The patent discloses and claims more than one billion compounds, some of which have stereo and optical isomers. Lurasidone, the (–)-enantiomer of an imide compound covered by the patent, is the active ingredient in Sunovion’s schizophrenia and bipolar depression drug LATUDA®. After Emcure filed Abbreviated New Drug Applications with the FDA, seeking approval to market generic versions of LATUDA®, Sumitomo sued for infringement. The claim construction question centered on what combination of enantiomers claim 14 encompassed. The Federal Circuit rejected Sumitomo’s attempt to “import limitations from the specification into the claim” and affirmed the district court, holding that the patent covers at least the specific orientation depicted in the claim, which is the active pharmaceutical ingredient in each party’s commercial product.