Addressing, among other things, where the upper limit of a claimed range lies for claim construction, the U.S. Court of Appeals for the Federal Circuit overturned a district court ruling that a claimed range included a margin of error and that the accused product met the claim recitation. Takeda Pharmaceutical Co. Ltd. v. Zydus Pharma USA, Inc., Case No. 13-1406 (Fed. Cir., Feb. 20, 2014) (Prost, J.).
Takeda Pharmaceutical and several related entities own patents claiming the formulation for the brand-name drug Prevacid® SolutabTM, a proton-pump inhibitor sold as an orally disintegrable tablet. The claimed formulation is directed to drug particles small enough to avoid a feeling of roughness in a patient’s mouth upon ingestion. Zydus Pharmaceuticals received U.S. Food and Drug Administration (FDA) approval for an Abbreviated New Drug Application (ANDA) covering a similar formulation, prompting Takeda to sue for infringement.
The claim term at issue recited “fine granules having an average particle diameter of 400 µm or less.” Adopting Takeda’s argument, the district court held that “400 µm or less” includes a deviation of ±10 percent, as would be universally understood by a person of ordinary skill in the art. Zydus appealed.
The Federal Circuit, relying in part on evidence that the claim does not qualify the term “400 µm,” and that the specification describes particles above 400 µm as being coarse, and that the construction exceeds the maximum particle size provided in the specification, disagreed. Rather, the Court determined that the evidence favored a narrower construction, citing the settled principle that the narrower of two equally acceptable claim constructions governs and held it to mean “precisely 400µm or less.”
In view of its narrower construction, the Federal Circuit vacated the district court’s ruling of literal infringement.
The Federal Circuit also addressed several issues relating to invalidity. Specifically, the Court rejected Zydus’ argument that the specification’s failure to provide a preferred method for measuring particle size rendered the asserted claim indefinite. Evidence showed that two methods work and that they provide similar results. According to the Court, the claim plainly requires a specified particle size. “That there is more than one way of determining the average particle diameter of a particular sample does not render that clear claim language indefinite.”
The Court also rejected the appellants’ arguments that the patent was invalid under the written description requirement for failing to show possession of tablets containing particles of the claimed size. The patent taught how to make particles of the correct size before tableting, but Zydus argued there was no teaching of tablets of the claimed particle size. The Court found there was no evidence that tableting affected particle size and rejected the argument.