Inherency often frustrates efforts to secure patents before the USPTO and defend them in court. Defeating or denying a patent generally requires showing that all elements of the claimed invention were previously known. Inherency provides an exception. By relying on inherency, an examiner may deny a patent or a competitor may defeat a patent without having to show that all elements of the invention were previously known. Par Pharmaceutical v. TWi Pharmaceuticals, Inc., 773 F.3d 1186, 1194-1195 (Fed.Cir. 2014) (“We have recognized that inherency may supply a missing limitation in an obviousness analysis.”) Allowing patents to be defeated or denied with less than a perfect showing, inherency has become a favorite assertion of examiners and competitors. The prevalence of inherency, however, is at odds with its limited legal reach. In the recent case ofMillennium Pharmaceuticals v. Sandoz, Inc., No. 2015-2066 (Fed.Cir. July 17, 2017), the CAFC further limited the ability of allegations of inherency to deny or defeat patents with less than perfect showings.

In Millennium Pharmaceuticals v. Sandoz, Inc., the CAFC further limited application of inherency by clarifying what constitutes an otherwise unpatentable invention. The invention at issue was a novel compound. The compound, however, was formed by a known technique using a reagent known to be applicable for that technique. As such, the invention could be characterized as the inherent result of an obvious and unpatentable method. So characterizing the compound, Sandoz attempted to rely on inherency to defeat the patent on the compound.

Noting that “the inventor’s own path itself never leads to a conclusion of obviousness” and “patentability shall not be negatived by the manner in which the invention was made”, the CAFC dismissed Sandoz’s attempted reliance on inherency. Millennium Pharmaceuticals, at 16. The dismissal of Sandoz’s attempted reliance on inherency makes clear an obvious method does not make all products produced by that method inherently unpatentable. Rather, more must be shown. In this regard, the CAFC criticized the evidenced offered by Sandoz noting, “No expert testified that they foresaw, or expected, or would have intended, the reaction … or that the resulting [compound] would have the long-sought properties and advantages.” Millennium Pharmaceuticals, at 17. This criticism of Sandoz’s evidence clearly indicates that relying on inherency to deny or defeat a patent on a product produced from an obvious method requires demonstrating that product was foreseeable or to be expected from practicing the method. Absent such a showing, the produced product cannot be considered unpatentably inherent.

The CAFC’s refusal to expand inherency to prove unpatentable unforeseen or unexpected compounds produced from what may be obvious methods is consistent with their previous limited application of inherency. The CAFC has limited its application of inherency to guard against patents secured on unpatentable inventions by virtue of some unrecognized feature that is necessarily present. “To hold otherwise would allow any formulation – no matter how [unpatentable] – to become patentable merely by testing and claiming an inherent property.”Santarus, Inc. v. Par Pharmaceutical, Inc., 694 F.3d 1344, 1354 (Fed.Cir. 2012). Thus, inherency is meant to be a safeguard against a specific type of disfavored patents. Protecting against a specific type of disfavored patent, “the concept of inherency must be limited when applied to obviousness, and is present only when the limitation at issue is the ‘natural result’ of the combination of prior art elements”. Par Pharmaceutical, 773 F.3d at 1195. Defeating or denying a patent based on inherency, accordingly, requires that the element not previously known be necessarily present, or naturally result, when the remaining known elements are combined to create the invention. Id at 1196. The combination of the remaining elements still must be shown in the prior art. See Allergan, Inc. v. Sandoz, Inc., 796 F.3d 1293, 1307 (Fed.Cir. 2015) (Refusing to apply the inherency when “the prior art did not disclose, either explicitly or implicitly, the claim formulation”.) As the combination of all other elements of the invention still must be shown, reliance on inherency to defeat or deny patents is limited to specific situations of less than perfect showings.

With its holding in Millennium Pharmaceuticals, the CAFC has further limited the applicability of inherency to deny or defeat patents to specific situations of less than perfect showings.


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