Takeda Pharmaceutical Co. v. Zydus Pharmaceuticals USA, Inc.
109 U.S.P.Q. 2d (BNA) 1825, 743 F.3d 1359, 2014 U.S. App. LEXIS 3072 (2014)
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Rule of Law:
When a patent claim specifies a numerical limit without qualifying language such as 'about,' it must be construed precisely as written, especially when the specification and prosecution history consistently treat that number as a strict boundary. A patent claim is not indefinite merely because it fails to specify a single measurement method, provided that different conventional methods known to a person skilled in the art yield substantially similar, non-outcome-determinative results.
Facts:
- Takeda owns the '994 patent for Prevacid® SoluTab™, an orally disintegrable tablet containing the active ingredient lansoprazole for treating acid reflux.
- The stated objective of the patent is to create a formulation with granules small enough to avoid a feeling of roughness in a patient's mouth.
- Claim 1 of the patent recites 'fine granules having an average particle diameter of 400 µm or less.'
- During the manufacturing process of such tablets, some individual drug cores fuse together to form larger particles known as 'hard agglomerates.'
- Zydus developed a generic version of Takeda's drug.
- The average particle diameter of Zydus's product measured 412.28 µm.
- Takeda argued that the true measurement should involve 'virtual dissection' of the hard agglomerates, which artificially separates the fused cores for measurement and results in a lower average particle size.
- The actual physical size of the fused hard agglomerates is what a patient would feel in their mouth.
Procedural Posture:
- Zydus filed an Abbreviated New Drug Application (ANDA) with the FDA to manufacture a generic version of Takeda's Prevacid® SoluTab™.
- Takeda sued Zydus in the U.S. District Court for the District of New Jersey for patent infringement.
- Zydus filed a counterclaim asserting that claim 1 of Takeda's '994 patent was invalid.
- The district court held a claim construction hearing and construed the term '400 µm or less' to mean '400 µm (±10%) or less.'
- Following a bench trial, the district court found that Zydus's product infringed Takeda's patent and that Zydus had failed to prove the patent was invalid.
- The district court entered an injunction prohibiting Zydus from manufacturing or selling its product.
- Zydus (appellant) appealed the district court's final judgment to the U.S. Court of Appeals for the Federal Circuit, with Takeda as the appellee.
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Issue:
Does a patent claim term specifying a particle size of '400 µm or less,' without any qualifying language, require a precise measurement, or does it implicitly include a standard measurement margin of error, such as ±10%?
Opinions:
Majority - Prost, Circuit Judge.
Yes, the claim term requires a precise measurement. The plain language of the claim, '400 µm or less,' is not qualified by ambiguous terms like 'about,' in contrast to other parts of the same claim that do use 'about.' This indicates the inventors' intent for a precise limit. The specification reinforces this by creating a clear dividing line, stating that conventional granules of '400 µm or more' produce the 'feeling of roughness' the invention aims to solve; allowing a 10% deviation would eliminate this distinction. Furthermore, during the patent's prosecution, the inventors distinguished their invention from prior art by arguing that the 'within 400 µm' limit was critical to preventing roughness. Although the specification uses 'about' in a few instances, it is always followed by a preference for an even smaller particle size, not an allowance for a larger one. Therefore, the district court's construction was erroneous, and since Zydus's product measured over 400 µm, there is no literal infringement. The court also affirmed the patent's validity, finding it not indefinite, because while multiple measurement techniques exist, the evidence showed they produced 'substantially similar' results and a person skilled in the art would know how to use them.
Analysis:
This decision reaffirms the principle of strict adherence to claim language in patent law, emphasizing that numerical limitations are to be read precisely unless the intrinsic evidence (the patent itself and its history) indicates otherwise. It serves as a crucial reminder for patent drafters to use words like 'about' intentionally and strategically to define the scope of their claims. The ruling on indefiniteness also provides clarity, establishing that the mere existence of multiple valid measurement techniques does not render a patent invalid unless a challenger can prove by clear and convincing evidence that the choice of method is outcome-determinative and the patent offers no guidance.
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