AstraZeneca AB v. Hanmi USA, Fed. Cir. Case No. 2013-1490 (nonprecedential)

A specification and a claim have distinct functions; a specification “describes” the invention and a claim “defines” the invention. One of the basic rules in claim construction is “don’t import limitations from a specification into claims.” However, there is a case-law recognized exception. A specification could narrow down the scope of a generic term in a claim when descriptions in the specification are clearly confined to specific members of the generic term. In other words, a specification could “define” the invention with disclaimer language.

AstraZeneca, innovator of Nexium (magnesium salt of esomeprazole), owns U.S. Patents 5,714,504 and 5,877,192 directed to salts of esomeprazole. Claim 1 of ‘504 Patent states:

1. A pharmaceutical formulation for oral administration comprising a pure solid state “alkaline
salt” of [esomeprazole] and a pharmaceutically acceptable carrier. (emphasis added)

Hanmi filed a 505(b)(2) application, also known as a paper NDA application, for “strontium salt” of esomeprazole with a certification that its product does not infringe any of the AstraZeneca patents. AstraZeneca sued Hanmi for patent infringement, asserting that “strontium salt” falls within the scope of “alkaline salt.”

There was no dispute that the ordinary meaning of “alkaline salt” is not limited to six salts identified in the specification. After the Markman hearing, however, the District Court construed the term “alkaline salt” as being limited to the six salts. The Federal Circuit affirmed the decision, holding that the descriptions in the specification “clearly confine the invention to the six identified cations, disclaiming anything else.”

To support the decision, the Federal Circuit cited three cases on disclaimer, Honeywell Int’l v. ITT Indus., 452 F.2d 1312 (Fed. Cir. 2006), Verizon Services v. Vonage Holdings, 503 F.3d 1295 (Fed. Cir. 2007) and SciMed Life Systems v. Adv. Cardiovascular Systems, 243 F.3d 1337 (Fed. Cir. 2001). The fact patterns of the three cases are similar in that their specifications use the term “the present invention” in connection with specific embodiments. The Federal Circuit ruled in each of the three cases that their generic terms are limited to the specific embodiments described due to disclaimer in the specification.

Similarly, AstraZeneca’s ‘504 Patent includes the following statement in the specification: “[t]he present invention refers to the new Na+, Mg2+, Li+, K+, Ca2+ and N+(R)4 salts of the single enantiomers of omeprazole…” (emphasis added). The abstract contained a similar statement identifying the six salts. The Federal Circuit found that the patentee “conveyed a clear and definitive meaning that it was disclaiming other members of the class” and affirmed the District Court’s decision.

The message of the Federal Circuit is clear; your detailed description could narrow down the claim scope. Thus, careful drafting of a specification is as important as good claim crafting for broader patent protection. The use of the term “the present invention” may not be the dispositive factor in finding disclaimer, but avoiding the term would reduce the risks associated with disclaimer in view of the case law.

It should be noted that ‘504 Patent does not provide any definition of “alkaline salt” nor general descriptions about the term. In patent drafting, therefore, providing a good definition of a generic term and telescoping detailed descriptions (i.e., covering various scopes from broadest to narrowest) would be useful to overcome disclaimer challenges.

Also, disclaimer issues are equally important for patent infringement analysis. Literal, generic embracement of an accused infringing product/method may not be the end of the game. For better infringement assessments, parties need to further investigate whether the specification disclaims the accused product/method with descriptions that the invention scope to the described embodiments.

The above article was written by Kisuk Lee, a principal in the St. Louis, MO office of Harness IP. Kisuk can be reached at 314-446-7670 or klee@harnessip.com.