Doctrine of Inherency Causes Stir at the CAFC

In Re Omeprazole Patent Litigation (04-1562) April 23, 2007

Astra sued several drug companies to prevent them from seeking permission from the FDA to market generic versions of Prilosec®. After a four-phase district court trial (which included a 52-day bench trial), Andrx Pharmaceuticals was found to infringe Astra's patents.

In an earlier proceeding, Astra filed suit in Korea against CKD, but CKD claimed to have a patent application of its own, which covered similar subject matter. Thereafter, Astra filed a patent application that was partially based on CKD's disclosure, but claimed the application of an enteric coating polymer layer, "thereby forming in situ a separating layer as a water soluble salt product."

The district court agreed that the CKD application did not expressly disclose the claim limitation of "forming in situ a separating layer." Nevertheless, the court that the formation was inherently disclosed based on the disclosure in the CKD application, and Astra's lack of "scientific proof with which to rebut or refute its prior admissions of inherency."

The CAFC agreed with the district court, even though one skilled in the art may not have recognized the inherent characteristics of the prior art:

[A] prior art reference without express reference to a claim limitation may nonetheless anticipate by inherency. See In re Cruciferous Sprout Litig., 301 F.3d 1343, 1349 (Fed. Cir. 2002). Moreover, "[i]nherency is not necessarily coterminous with knowledge of those of ordinary skill in the art. Artisans of ordinary skill may not recognize the inherent characteristics or functioning of the prior art." Id.; Schering Corp. v. Geneva Pharms., 339 F.3d 1373, 1377 (Fed. Cir. 2003) (rejecting the contention that inherent anticipation requires recognition in the prior art). Though [Astra's inventors] may not have recognized that a characteristic of CKD’s Method A ingredients, disclosed in the CKD Patent Application, resulted in an in situ formation of a separating layer, the in situ formation was inherent.

The record shows formation of the in situ separating layer in the prior art even though that process was not recognized at the time. The new realization alone does not render that necessary prior art patentable . . . Despite CKD’s denials, [Astra's inventors] realized and explained that CKD’s OMP tablet’s formation of a separating layer was a natural result flowing from the combination of certain ingredients listed in Method A. That explanation, however, does not make that prior art patentable. The ingredients and protocols CKD gave to the KIPO and Astra in 1993 and 1994 necessarily resulted in in situ formation of a separating layer. Thus, the trial court correctly found inherent anticipation.

Judge Newman's dissent

Newman accused the majority of straying from the principle of inherency, which requires that any information missing from a reference would nonetheless be known to be present in the subject matter of the reference, when viewed by persons experienced in the field of the invention. "However anticipation by inherent disclosure is appropriate only when the reference discloses prior art that must necessarily include the unstated limitation, or the reference cannot inherently anticipate the claims."

Newman also argued that the majority's decision confused the law governing patentability of a newly discovered use of a known composition (which is achieved by "process" claim), with the patentability of the known composition itself:

The claims at issue are not directed to a composition; they are directed to a process for forming a sublayer from known ingredients . . . The Astra process is not described in the prior art, although Astra admitted that it believed that the Korean company Chong Kun Dan Corporation (CKD) had made such a product. It is not disputed that such a sublayer does not form under the conditions in the CKD patent application. No such reaction is described in CKD's Korean patent application, nor the conditions that could have produced such a product. Nonetheless, my colleagues rule that the process discovered by Astra is "inherently anticipated" by the CKD application. That is not the law of either anticipation or inherency. I must, respectfully, dissent.

This could be a good candidate for en banc review. Inherency has long been a sticking point for the CAFC. Some of the CAFC panels have stated that recognition is required, while other panels stated that recognition is not required.

For an excellent paper on inherency, see Dan Burk and Mark Lemley's article, coincidentally titled, "Inherency," published in 2005:

Inherency is also perhaps the most elusive doctrine in all of patent law. The cases appear to flatly contradict each other, are often accompanied by dissents, and in the last three years alone have triggered one abortive en banc rehearing and strong calls for a second. In particular, the courts have split sharply over whether an element can be inherent in a prior art reference even if people of ordinary skill in the art do not appreciate the existence of that element.

In this Article, we argue that this confusion is largely unnecessary. While many courts have recited as gospel the idea that inherency requires knowledge or appreciation of the inherent element, in no case does the application of the inherency doctrine actually turn on knowledge of the element. Rather, the inherency cases are all ultimately about whether the public already gets the benefit of the claimed element or invention. If the public already benefits from the invention, even if they don't know why, the invention is inherent in the prior art. If the public doesn't benefit from the invention, there is no inherency.