Reasonable certainty: Ten years of Nautilus

Ten years ago, the Supreme Court formulated the “reasonable certainty” standard with regard to Section 112(b) of the patent statute. Section 112(b), which requires that a valid patent explicitly define what constitutes its invention, has often been the focus of defenses seeking to invalidate patent claims citing indefiniteness. In its unanimous decision in Nautilus, Inc. v. Biosig Instruments, Inc., the Supreme Court sought to clarify Section 112(b)’s definiteness requirement with its “reasonable certainty” standard, writing that:

To determine the proper office of the definiteness command, therefore, we must reconcile concerns that tug in opposite directions. Cognizant of the competing concerns, we read §112, ¶2 to require that a patent’s claims, viewed in light of the specification and prosecution history, inform those skilled in the art about the scope of the invention with reasonable certainty. The definiteness requirement, so understood, mandates clarity, while recognizing that absolute precision is unattainable.

In defining the statute’s clarity and precision demand, the Supreme Court rejected the Federal Circuit’s “not amenable to construction or insolubly ambiguous” standard, finding that the formulation lacks the precision that Section 112(b) demands. However, the Court did not give concrete examples of any claims or claim terms that might survive a validity challenge under the “insolubly ambiguous” test but would not pass the “reasonable certainty” formulation. In lieu of this information, we take a look at post-Nautilus Federal Circuit decisions in order to provide some clarity to the Supreme Court’s “reasonable certainty” standard.

Reasonable certainty invalidated through inability to resolve ambiguities in technical definitions

In Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc., Appellants submitted Abbreviated New Drug Applications seeking approval to market generic versions of Copaxone® and were subsequently sued by Teva. Claim 1 of the ’808 patent recited a method of making a product called copolymer-1:

A method of manufacturing copolymer-1, comprising reacting protected copolymer-1 with hydrobromic acid to form trifluoroacetyl copolymer-1, treating said trifluoroacetyl copolymer-1 with aqueous piperidine solution to form copolymer-1, and purifying said copolymer-1, to result in copolymer-1 having a molecular weight of about 5 to 9 kilodaltons. (emphasis added)

Relevant to the indefiniteness analysis, the district court rejected Appellants’ argument that the term “molecular weight” was indefinite. The Federal Circuit reversed, clarifying that, on the one hand, they recognized that the definiteness requirement must take into account the inherent limitations of language, but also that a patent must be precise enough to afford clear notice of what is claimed. Using these guiding principles, the Federal Circuit held that the claim was indefinite because it did not convey with reasonable certainty the measure of molecular weight to be used. Specifically, the Federal Circuit pointed out that “molecular weight” was recited in the claim, but the meaning was not specified. The parties also agreed that “molecular weight” could be measured three different ways, and they agreed that each way would yield different results. Further, there was no express definition given to the term in the specification, and the prosecution history did not provide guidance as to which measure to use. According to the Federal Circuit, “molecular weight,” when read in light of the intrinsic and extrinsic evidence, did not inform those skilled in the art about the scope of the invention with reasonable certainty. Thus, the claim was invalid for indefiniteness.

Reasonable certainty validated as intrinsic record and extrinsic evidence are determined capable of informing artisan

In Niazi Licensing Corp. v. St. Jude Medical S.C., Inc., the Federal Circuit heard an appeal regarding a patent related to medical treatments for congestive heart failure that claimed, inter alia, “a double catheter, comprising: an outer, resilient catheter [and] . . an inner, pliable catheter.” In relevant part, the district court determined that the terms “resilient” and pliable” in the asserted independent claims rendered those claims and their dependents as indefinite. Patent holder Niazi appealed.

The Federal Circuit held that, while the terms are broad, they are not uncertain, and the district court erred in holding otherwise. The Federal Circuit explained that the “reasonable certainty” requirement of indefiniteness “exists to strike a delicate balance, affording clear notice of what is claimed while recognizing [ ] inherent limitations [of language].”‎ The Federal Circuit acknowledged that words or terms of degree in a claim may result in broader claim scope, but that “a claim is not indefinite just because it is broad.”

On the other hand, the Federal Circuit reiterated that terms of degree render a claim indefinite where the intrinsic evidence (or relevant extrinsic evidence) provides insufficient guidance as to any objective boundaries for the claim. As to the terms at issue, the Federal Circuit found that the intrinsic record and extrinsic evidence were sufficient to inform a skilled artisan, with reasonable certainty, of the meanings of “resilient” and “pliable.” For example, the Federal Circuit pointed to the language of the claim itself – that the outer catheter must have “shape memory” and “sufficient stiffness.” The written description provided similar guidance, explaining that the outer catheter has a “braided design” and is made of materials like silastic or similar materials such that the outer catheter has “sufficient shape memory to return to its original shape when undistorted.” Thus, the Federal Circuit reversed the district court as to indefiniteness.

Key takeaways

Looking at these cases together, some takeaways stand out. The patent specification must conclude with one or more claims that distinctly claim the invention. To satisfy the definiteness requirement, a claim must inform a person of ordinary skill in the art of the invention’s scope with reasonable certainty when read in view of the specification and prosecution history. The intrinsic record (and extrinsic evidence, where relevant and available) is crucial to meeting the “reasonable certainty” requirement. When drafting or defending the validity of a patent, practitioners should ask: Do the claims, specification, and prosecution history provide guideposts for a skilled artisan to determine the scope of the claims? Does the patent provide objective boundaries, including exemplary designs and specific examples of what the claim term means? If so, the claims are more likely to be definite. On the other hand, if the claim term is one of degree where the record evidence provides insufficient guidance as to any objective boundaries for the claims, the claims are more likely to be indefinite. Answering these questions could be critical to your next patent matter.

For any further questions and clarifications about patent matters, please contact the authors of this alert.