Claim Language Having No Patentable Weight

In a patent application, an applicant is entitled to be their own lexicographer. Patent practitioners prepare patent applications based on an applicant’s invention disclosure and draft a patent application to describe an invention, carefully and faithfully following applicants’ description of their inventions. Certain claim language, even though chosen or preferred by an applicant, may present potential claim construction issues to have no patentable weight under the governing law.

The consequences of having no patentable weight can be grave. Under relevant case law, claim language having no patentable weight may not distinguish the claimed invention from the prior art, support an objective indicia of non-obviousness, or be considered as an inventive concept for Alice step two.

Whether a certain claim limitation is accorded with patentable weight or not is a claim construction issue and addressed during claim construction hearing.

It is known that certain types of claim language may be considered to have no patentable weight. As one example, a preamble is generally considered to have no patentable weight and therefore, not limiting. However, preamble language providing essential structure can be limiting and have patentable weight. In determining whether claim language is limiting or not, courts look at a claim as a whole, the specification and the prosecution history.

For example, in Sanofi Mature IP v. Mylan Laboratories Limited, Appeal No. 2018-1203 (Fed. Cir. decided Feb. 5, 2019), the Federal Circuit found that the preamble of “[a] method of increasing survival” is limiting. The Federal Circuit reasoned that “there is a direct link between the claim as a whole and the preamble, which provides an antecedent basis for ‘in need thereof.’” The phrase, “in need thereof,” was in the body of the claim.  The Federal Circuit further found that the specification highlighted that “patients in the cabazitaxel group demonstrated increased overall survival rates compared to patients treated with mitoxantrone and prednisone.” The Federal Circuit rejected the petitioner’s arguments that the prosecution history supported the nonlimiting preamble. 

On the other hand, the Federal Circuit found that the preamble languages such as “[a] scratch off marking label” and “[a] process for waterproofing leather” are not limiting because the preamble language only added an intended use and the prosecution history indicated the applicant’s statement that certain language was not a claim limitation. See Marrin v. Griffin, 599 F.3d. 1290 (Fed. Cir. 2010); Outdry Technologies Corp. v. GEOX S.P.A., 859 F.3d. 1364 (Fed. Cir. 2017). 

Claim limitations reciting mental steps, an intended use, and an intended result may be considered as having no patentable weight. See Praxair Distribution, Inc. v. Mallinckrodt Hosp., 890 F.3d 1024 (Fed. Cir. 2018); In re Dillon, 919 F.2d 688 (Fed. Cir. 1990);Roche Palo Alto LLC v. Apotex, Inc., 531 F.3d 1372 (Fed. Cir. 2008) (“in a stabilizing amount” is an intended result and not a claim limitation for infringement purposes in a composition claim); Bristol-Myers Squibb Co. v. Ben Venue Labs., Inc., 246 F.3d 1368 (Fed. Cir. 2001) (The expression, “a method for treating a cancer patient to effect regression of a taxol-sensitive tumor, said method being associated with reduced hematologic toxicity,” in the preambles of claims 5 and 8 is only a statement of purpose and an intended result)

A product-by-process claim is another claim language that poses a question of whether patentable weight should be given or not.  A process limitation has no patentable weight unless the process limitation imparts a structural difference. See In re Pond (Fed. Cir. 2012); Amgen Inc. v. F. Hoffmann-La Roche Ltd., 580 F.3d 1340 (Fed. Cir. 2009). When a question is raised as to whether a process limitation of a product-by-process claim should be interpreted as a structural limitation or not, the default is to apply structural interpretation. See In re Nordt Development Co., LLC., 881 F.3d 1371 (Fed. Cir. 2018). An interesting twist to construction of a product-by-process claim is that a process limitation will be considered as limiting in the patent infringement context. See Amgen Inc., 580 F.3d at 1370 (“As a result, a product-by-process claim is not infringed by a product made by a process other than the one recited in the claim. For product-by-process claims, that which anticipates if earlier does not necessarily infringe if later.”). 

Claim limitations reciting optional and conditional steps, theory of operation,  wherein clauses and whereby clauses will likely trigger the issue of whether patentable weight should be given or not.  

Patent practitioners should be aware of claim construction issues involving the foregoing types of claim language in drafting patent claims. If such patent claims are challenged, claim construction decisions resulting in no patentable weight for certain claim terms will likely impact the validity and/or infringement of patent claims. 

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