“Consisting Of” Creates Closed Group and Provides Avenue to Avoid Infringement

Shire Development v. Watson Pharma (Fed. Cir. 2017) [16-1785-opinion-2-8-2017-11]

In a short opinion, the Federal Circuit has reversed a lower court infringement claim — holding instead that Watson’s generic product does not infringe.

In U.S. Patent law, it is an act of infringement to file an Abbreviated New Drug Application (ANDA) with the Food and Drug Administration (FDA) seeking to market a generic version of a patented drug listed in the FDA Orange Book.  That is just what Watson did here and Shire sued on its U.S. Patent No. 6,773,720.  The drug at issue is LIALDA, a mesalamine drug used to treat ulcerative colitis.  The claimed compound includes the following limitation:

said outer hydrophilic matrix consists of compounds selected from the group consisting of polymers or copolymers of acrylic or methacrylic acid, alkylvinyl polymers, hydroxyalkyl celluloses, carboxyalkyl celluloses, polysaccharides, dextrins, pectins, starches and derivatives, alginic acid, and natural or synthetic gums;

The basic question on appeal the scope of the claimed Markush group and whether it is a “closed group.”   In other words: is the hydrophilic matrix limited only to substances in the list.  This issue is a deciding factor in the case because Watson’s proposed generic version includes an inner hydrophilic matrix with additional substances not listed.

Consisting Of: In its analysis, the Federal Circuit began by recognizing that the phrase “consisting of” and “consists of” are terms of art in patent claims and “creates a very strong presumption that that claim element is ‘closed’ and therefore ‘exclude[s] any elements, steps, or ingredients not specified in the claim.'” quoting Multilayer Stretch Cling Film Holdings, 831 F.3d 1350, 1358 and AFG Indus., Inc. v. Cardinal IG Co., 239 F.3d 1239, 1245 (Fed. Cir. 2001). Although the presumption of standard meaning can be overcome, it requires that the patentee have documented the redefinition during prosecution in ways ““unmistakably manifest.”  However, as an exception to the standard meaning, the court may still find infringement when elements are added to the group that are “unrelated to the invention.” Norian Corp. v. Stryker Corp., 363 F.3d 1321, 1331 (Fed Cir. 2004).

Here, the generic proposal includes magnesium stearate within the matrix.  Citing Noriam, the district court still found infringement – noting that magnesium stearate is lipophilic and therefore including it within the hydrophilic outer matrix was “unrelated to the invention.”

On appeal, the Federal Circuit has reversed – noting that the “unrelated” exception is a “rare exception” to the general rule that “consisting of” closes the group.  The court explained here that the existence of magnesium stearate would certainly impact the invention by placing a lipophilic compound in an area designed to be hydrophilic.

When the outer, hydrophilic matrix interacts with a person’s digestive fluids, the matrix creates a swollen barrier preventing aqueous solution from reaching the inner, lipophilic matrix. This delay permits the product to proceed through the digestive system until the water breaks apart the outer matrix, releasing the lipophilic granules.

The court here found that the adding mag stearate to the outer layer has the potential of changing this process.  As such, the Norian exception does not apply, and Shire’s Markush claim is closed.  No infringement.

Question: Tell me why did Shire use “consisting of” instead of “comprising” or “consisting essentially of”?

Answer: In response to this inquiry, a reader correctly pointed us to MPEP 2173.05(h), which states” “It is improper to use the term ‘comprising’ instead of ‘consisting of’ [in a Markush group.]”  Citing Ex parte Dotter, 12 USPQ 382 (Bd. App. 1931).  In Dotter, the patentee sought a patent on an air purifier apparatus that relied upon a “mass of loose granules of a natural material of the group comprising wood and grains.”  Although the Board objected to the use of “comprising”, it did not explain the legal basis for its objection. Board wrote:

The word “comprising” does not exclude other materials besides wood and grains. It is considered that the word “consisting” would be more appropriate in this relation in confining the material strictly to these materials –wood and grains. If this formal change is made in claim 17 it may be allowed.

The word “comprising” does not exclude other materials besides wood and grains. It is considered that the word “consisting” would be more appropriate in this relation in confining the material strictly to these materials –wood and grains. If this formal change is made in claim 17 it may be allowed.

It turns out that the MPEP’s quote is from a case, just not Dotter.  It comes from In the precedential case In re Harnish, 631 F.2d 716, 723 (C.C.P.A. 1980)(“It is improper to use the term ‘comprising’ instead of ‘consisting of.'”)  Again, however, the court fails to justify its reasoning or basis for that objection. However, there is a slight suggestion elsewhere in the decision that the objection might be based on lack of unity of invention.

An interesting bit of the claim at issue here is that they make double-use of the consist/consisting of language.

said outer hydrophilic matrix consists of compounds selected from the group consisting of…

I wonder whether the PTO would object to a reformulation claiming the “matrix comprising compounds selected from the group consisting of …” Thoughts?