Claims Containing Descriptive Words are not Necessarily Indefinite

The CAFC recently overturned a district court’s decision holding that claims containing the terms “resilient” and “pliable” were indefinite.  The CAFC went out of its way to indicate that a claim is not indefinite just because it is broad.^[1]  The CAFC instead reiterated the indefiniteness standard set forth by the Supreme Court in Nautilus – a claim is indefinite “only if, when ‘read in light of the specification’ and ‘prosecution history,’ it ‘fail[s] to inform, with reasonable certainty, those skilled in the art about the scope of the invention.'”^[2]

The court examined the intrinsic record – the patent’s claims, written description, and prosecution history – and concluded that the “resilient” and pliable” were sufficiently clear to inform the skilled artisan, with reasonable certainty, of their meaning.

With regard to the term “resilient,” claim 1 recites “an outer, resilient catheter having shape memory.”  The CAFC found that the claim language itself consequently provides guidance on what the term means.^[3]  Numerous dependent claims also inform the meaning of this term, by providing examples of resilient materials of which the catheter could be made.^[4]  The CAFC further stated that the written description also provides guidance with respect to the design of an outer, resilient catheter and materials of which the catheter could be made.^[5]  The CAFC concluded that an ordinarily skilled artisan reading the claims and the written description would thus know of exemplary materials that can be used to make a resilient outer layer.^[6]

Regarding the term “pliable,” the claims recite “an inner, pliable catheter slidably disposed in the outer catheter.”^[7]  While acknowledging that the claims provide less guidance on this term, the CAFC stated that the written description contains numerous examples of a “pliable” inner catheter. For instance, the written description explains that the inner catheter “is constructed of a more pliable, soft material such as silicone” when compared to the resilient outer catheter.^[8]

The court concluded that for purposes of the definiteness inquiry, the problem faced by patentees when using descriptive words (or terms of degree) in their claims is not the potential breadth of those claims. Rather, it is whether the descriptive phrasing results in a claim that “fail[s] to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”^[9]

Given the CAFC’s focus on the written description’s examples of the structure and materials that make a catheter “resilient” and “pliable,” drafters would be wise to include descriptive terms (or terms of degree) in claims, but make sure that the specification contains examples of embodiments of those terms.

1 Niazi Licensing Corp. v. St. Jude Medical S.C., Inc., Case No. 2021-1864 at p. 11 (Fed. Cir. April 11, 2022).
2 Id. at p. 9, citing Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 901 (2014).
3 Id. at p. 14.
4 Id.
5 Id.
6 Id. at p. 15.
7 Id.
8 Id.
9 Id. at p. 9 (internal citations omitted).