Federal Circuit panel splits on inherency caseApril 24, 2007

In a second appeal involving patents relating to the original "Purple Pill®," a panel of the Federal Circuit split on whether an earlier patent application by a Korean company inherently anticipated one of AstraZeneca's patents covering the popular heartburn medication Prilosec® (omeprazole). The panel majority held that a process disclosed in a Korean patent application by Chong Kun Dan Corp. (CKD) would have inherently produced the single disputed limitation, forming in situ a separating layer in the drug, and as a result, anticipated all but one of the claims at issue. The final claim was held to be obvious as a mere substitution of one known alkaline reacting compound for another.

Judge Newman, in dissent, argued that the science showed that such a separating layer was not formed, and criticized the panel majority for failing to fill in this scientific gap. She also pointed out the Federal Circuit's inconsistency in its inherency cases, noting that a leading treatise on patent law has recognized this, and taking the panel majority to task for bringing "further uncertainty to this important aspect of patent law."

More details of the case after the jump.

This case stemmed from a larger case AstraZeneca filed against several defendants. The case was split into four phases, two for the product patents (the '505 and '230 patents) and two for the patent covering the method making the pill. Several companies were found to have infringed the product patents, and that finding was already affirmed by the Federal Circuit in 2003. Claim 1 of the method patent is representative (the disputed term bolded and underlined):

1. A process for preparing an oral pharmaceutical formulation comprising the steps of: forming a core material comprising a proton pump inhibitor and at least one alkaline reacting compound, wherein the concentration of the alkaline reacting compound is about 0.1 mmol/g dry ingredients in the alkaline containing part of the core material, and

applying an enteric coating polymer layer so as to surround the core material thereby forming in situ a separating layer as a water soluble salt product between the alkaline compound and the enteric coating polymer.

The parties disputed whether the closest prior art reference, the CKD patent application, anticipated this claim. The only issue was whether the process disclosed in the CKD application would inherently form an in situ separating layer, as it was undisputed that such formation was not explicitly disclosed in the reference. The majority of the panel found such inherency, and invalidated the claim. In large part, the finding of inherency was based on AstraZeneca's statements to the Korean courts in proceedings between it and CKD. In that proceeding, AstraZeneca accused CKD of infringement of its Korean patents covering Prilosec®. As a result, AstraZeneca argued that the CKD process "resulted in the in situ formation of a separating layer," did so "even though [CKD's method] does not have a separate step of applying the separating layer," and that it was "inherent in the process" of the CKD method that such a layer was formed. As stated by the court:

Astra[Zeneca] does not deny these statements. Furthermore, as noted by the district court: "If Astra[Zeneca] had scientific proof with which to rebut or refute its prior admissions of inherency, it surely would have put on such proof. Astra[Zeneca] did not."

Based largely on these earlier statements made in an attempt to obtain a judgment of infringement against the CKD process, the court found claim 1 (and several other dependent claims) inherently anticipated by CKD's application.

For similar reasons, the panel majority also found claim 9 of the patent obvious. Claim 9 reads:

9. The process according to claim 1, wherein the alkaline reacting compound is an alkaline salt of phosphoric acid, carbonic acid or silicic acid.

In the Korean case, AstraZeneca took the position that "L-arginine [the alkali used in the CKD process] is generally known as an alkaline reactive compound," and that it could easily "substitute alkaline reactive compounds [for the] L-arginine in" CKD's process. These statements (along with expert testimony) were, like with the other claims, sufficient for the court to affirm the invalidity of this claim.

Based on the decision, both the district court and the Federal Circuit panel majority gave great weight to AstraZeneca's previous positions in the Korean litigation. There, AstraZeneca was attempting to show that the CKD method infringed its Korean patents on the composition. However, because AstraZeneca's earliest priority date for its method patent was after CKD's publication date, those same statements ended up killing its method patent.

Judge Newman dissented, and pointed out arguable gaps in the scientific proof of inherency and obviousness. She also pointed out that there is confusion in the Federal Circuit's inherency jurisprudence, particularly with regard to whether it is necessary that one of ordinary skill in the art would have recognized the inherency of the disclosure. It seems that this confusion will continue at least for the time being.

To read the full decision in In re Omeprazole Patent Litig., click here.

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