Case No. 2013-1490 (Dyk, Moore, Taranto) (nonprecedential)
Here’s an easy New Year’s resolution: don’t use “the present invention” to describe example embodiments in a patent specification. Based on the troubles caused in AstraZeneca v. Hanmi, it’s a good practice throughout patent preparation and prosecution to red-flag “invention” anytime it would appear. The case is a pretty straightforward reminder of how even broadly, well-differentiated claims can be pared in scope by narrow specification drafting using terms like “the present invention.”
AstraZeneca owned US Patents 5,714,504 and child 5,877,192 covering the active ingredient in Nexium, the magnesium salt of esomeprazole, a proton pump inhibitor useful for reducing stomach acid. Hanmi sought approval from the FDA to market a similar drug using the strontium salt of esomeprazole as a generic. AstraZeneca brought suit under § 271(e)(2)(A), alleging that the strontium esomeprazole formulation infringed the following broad claim:
1. A pharmaceutical formulation for oral administration comprising a pure solid state alkaline salt of the (-)-enantiomer of [omeprazole] and a pharmaceutically acceptable carrier.
A dependent claim separately limited the “alkaline salt” to one of sodium, magnesium, lithium, potassium, calcium, and ammonium. Despite the plain language and implication from claim differentiation, the district court declined to construe “alkaline salt” in claim 1 to include a strontium salt, an alkaline, used in Hanmi’s generic.
The Federal Circuit affirmed this narrow construction. The culprit? Disclaimer / narrow redefinition in the specification. Two parts of the ‘504 patent were key. In the first sentence of the detailed description section:
The present invention refers to the new Na+, Mg2+, Li+, K+, Ca2+ or N+(R)4 salts of the single enantiomers of omeprazole, where R is an alkyl with 1-4 carbon atoms, i.e. Na+, Mg2+, Li+, K+, Ca2+ or N+(R)4 salts
And then in the abstract:
The novel optically pure compounds Na+, Mg2+, Li+, K+, Ca2+ or N+(R)4 salts of [omeprazole]
Citing Verizon v. Vonage, Honeywell v. ITT, and SciMed v. Advanced Cardiovascular Systems, the Federal Circuit agreed that this language was a clear disclaimer that defined the invention as the listed salts and not strontium, stating, “[b]y conspicuously choosing only certain members of the class, and using the language it did, AstraZeneca conveyed a clear and definitive meaning that it was disclaiming other members of the class.”
Having found clear disclaimer, the court then disposed of all other evidence of breadth. Specifically, the ‘504 patent later disclosed that “alkaline salts” were “exemplified” by four of the specific alkaline elements, suggesting that these were merely non-limiting examples. But the passage did not include all six disclosed elements in its “exemplary” treatment and also stated that it was repeating the information “mentioned above” – where the block-quoted disclaimer was found.
In a different attempt at breadth, the applicant in prosecution of the ‘504 patent had purposefully broadened the claims from the listed elements to recite any “alkaline salt” and explicitly argued to the Examiner that the evidence of patentability supported “the full scope of the genus of alkaline salts disclosed in the application and as claimed herein.” The court dismissed this. The “genus” could be referring to the subset of six disclosed alkaline elements, and the “disclosed in the application” language certainly referred to the limited six embodiments.
Lastly, the claim differentiation argument. As seen above, limiting the independent claim to only the six disclosed alkaline species made the dependent claim listing those species redundant. Oh well; the court found that clear disclaimer easily overrode any possibility of claim differentiation:
AstraZeneca presses an argument based on claim differentiation, noting that each independent claim reciting an “alkaline salt” has a dependent claim that differs only by the addition of “wherein the alkaline salt is a Na+, Mg2+, Li+, K+, Ca2+ or N+(R)4 salt.” See ’504 patent, col. 14, lines 14-15; id., col. 14, lines 48-49. But “the doctrine of claim differentiation does not . . . override clear statements of scope in the specification.” The Toro Co. v. White Consol. Indus., Inc., 199 F.3d 1295, 1302 (Fed. Cir. 1999). Here, what otherwise might be an inference from differences in claim language cannot override the unmistakable limitation of “alkaline salt” set out in the written description.
Claim construction and non-infringement based on the same affirmed.
Lessons: Terms like “the present invention is” or “the novel concepts are” in a specification stand an excellent chance of limiting the whole patent to whatever immediately follows them. Avoid their use, or be extremely careful to use them only in connection with very general prefacing statements that are clearly set apart from example embodiments. This guidance is likely old news to most practitioners, and most patent drafting best practices have for years avoided explicitly identifying a point of novelty in the specification – with terms like “invention,” “new,” “advance,” “novel,” etc being labelled patent profanity. Nonetheless, AstraZeneca v. Hanmi reemphasizes the importance of following this lesson. As seen here, once a disclaimer is written into a specification, it can counter all later attempts at breadth in claim drafting, prosecution, and litigation.
Comment: The asserted patents here were pretty old, and as stated above, I suspect that most drafting practices have already abandoned usage of “invention” in the specification. Nonetheless, a quick search of publications with filing dates in the last five years still turned up approximately 1 in 5 having the phrase “the present invention” in the specification. These may be legacy continuations and/or use the phrase very carefully in a non-limiting fashion, but I’m guessing at least some non-negligible percentage of new disclosures are still being drafted using the phrase in a narrowing fashion.
Judge Taranto, the author here, was lead counsel for Verizon in the cited Verizon v. Vonage case from 2007. There, the court reversed Verizon’s favorable claim construction on appeal due to disclaimer from use of “the present invention.” It would seem Judge Taranto held no absolute grudge against disclaimer jurisprudence from that case.