Omeprazole is the best-selling proton pump inhibitor sold under brand name Prilosec®. The drug operates by inhibiting the production of gastric acid, but only operates properly when administered within an enteric coating and an additional separating layer. AstraZeneca's Patent No. 6,013,281 relates to the process of forming the coated pill. In a 2-1 decision, the Court of Appeals for the Federal Circuit (CAFC) found the '281 patent invalid as inherently anticipated.
A prior Korean patent application recites all but one claim limitation of the asserted '281 patent.* That limitation requires that the separating layer be formed "in situ." The trial court found, and CAFC affirmed that the in situ separation necessarily formed when practicing the prior art.
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 [prior art] ingredients and protocols ... necessarily resulted in in situ formation of a separating layer. Thus, the trial court correctly found inherent anticipation.
Concluding for the 2-1 majority, Judge Rader affirmed the finding of invalidy.
In dissent, Judge Pauline Newman took issue with the majority's legal analysis.
Applying a novel theory of "inherent anticipation," the court invalidates Astra's patent on a newly discovered chemical process. . . . The court's explanation and citation of authority suggest that my colleagues have confused the law governing patentability of a newly discovered use of a known composition, which is achieved by "process" claim,1 with the unpatentability of the known composition itself.
Judge Newman insisted that inherency requires that the 'inherent information" still "be known to be present in the subject matter of the reference, when viewed by persons experienced in the field of the invention." In addition, any secret tests using the Korean method cannot serve as prior art because they are not public.
- * One of the asserted claims (Claim 9) was not inherently anticipated, but was found obvious.