Over a vigorous dissent that shed light on the Court’s divergent inherent anticipation jurisprudence, a panel majority of the U.S. Court of Appeals for the Federal Circuit affirmed a finding of invalidity based on anticipation by inherency. In re Omeprazole Patent Litigation, Case Nos. 04-1562, -1563, -1589 (Fed. Cir., Apr. 23, 2007) (Rader J.; Newman, J., dissenting).

Omeprazole is sold by AstraZeneca under brand name Prilosec®, a drug that inhibits the production of gastric acid when administered within an enteric coating and an additional separating layer. AstraZeneca’s Patent No. 6,013,281 (the ’281 patent) claims the process of forming the pharmaceutical formulation that is composed of a core containing an active alkaline reacting compound (ARC), a water-soluble separating layer and an enteric coating layer. The separating layer is created by an in situ reaction between the enteric coating material and the ARC. Andrx sought to market a generic version of AstraZeneca’s drug, arguing that its product did not infringe the ’281 patent because the separating layer in Andrx’s generic version contained talc and was not water soluble. After a lengthy trial, the district court entered a final judgment finding that Andrx literally infringed the asserted claims of the ’281 patent, but also found the claims anticipated or obvious.

On appeal, Andrx argued that the district court erred in finding that its product infringes the ’281 patent because it does not have a water-soluble separating layer, but instead a layer composed of almost 50 percent talc. The Federal Circuit agreed with the district court, finding that the claim phrase “a water soluble salt,” permits the inclusion of talc. The Court pointed to evidence produced at trial with regard to related patents that also recite a water-soluble salt product despite the presence of a talc and to the ’281 patent’s five preferred embodiments, which state that they contain talc.

Turning to anticipation, the prior art at issue was a Korean patent application published two years before AstraZeneca’s earliest priority date. The patent issuing from that application had been the basis for a lawsuit in Korea between AstraZeneca and the Korean applicant, Chong Kun Dan Corp. (CKD). CKD’s Korean patent publications described compositions with no enteric coating processes. CKD maintained its enteric coating process—its “know how”—as a trade secret under Korean patent law. The CKD patent application purports to disclose an omeprazole formulation whose stability relies on the zwitterionic amino acids in the core. The CKD patent publication does not disclose any enteric coating process conditions or the basic details concerning enteric coatings. However, in the Korean action AstraZeneca relied on test results and argued that the formation of a separating layer naturally results from the CKD process. CKD’s scientists steadfastly maintained throughout that their formulation did not contain a separating layer. The Federal Circuit pointed to the trial record, which showed that the ingredients and protocols CKD provided in the Korean action necessarily resulted in in situ formation of a separating layer and concluded that the trial court correctly found inherent anticipation.

In a stern dissent, Judge Newman accused the panel majority of contravening a vast body of precedent and pointed to the undisputed fact that no reference explicitly or inherently teaches AstraZeneca’s claimed process.