In Cox Communications, Inc. v. Sprint Communication Co., the Federal Circuit reversed a district court ruling holding six of Sprint’s patents invalid as indefinite. The definiteness dispute centered on the term “processing system,” which performed the function of transforming and routing telephone signals through a data network. Cox argued that “processing system” is a structural limitation that is only described functionally by the claims and specifications, such that the bounds of the invention were insufficiently defined. The Federal Circuit disagreed, holding that the scope of the claims could be understood by one of the skill in the art with reasonable certainty. While the case involved communications technology, there are several interesting aspects of the opinion that could be applied in the ANDA context.

First, the Court considered the extent to which the disputed claim element related to “the point of novelty” of the claimed invention. The Court compared several claims with and without the “processing system” term, noting that “the point of novelty resides with the steps of [the] methods, not with the machine that performs them.” The court reasoned that if a term does not alter the scope of the claims, “it is difficult to see how [such a term] would prevent the claims . . . from serving their notice function under § 112, ¶ 2.”

Notably, Judge Newman, in an opinion concurring in the judgment, disagreed with the Court’s particular mode of comparative omission analysis in which a challenged term is removed from the claim and the court then decides whether the meaning of the claim has been altered. She reasoned that judicial determination of compliance with the “reasonable certainty” definiteness test of Nautilus cannot be achieved by deleting challenged terms—there is no basis in precedent for such claim analysis. Judge Newman nonetheless found the claims to be definite by examining the knowledge of those skilled in the art and the patent specifications.
Second, the Court emphasized that “the dispositive question” under Nautilus is whether claims, not terms, inform those of skill in the art about the scope of the invention with reasonable certainty. While recognizing that the definiteness analysis often is “inextricably intertwined with claim construction” and the common practice of focusing on individual terms is a “helpful tool,” the ultimate definiteness question must focus on the claims. In this case, the Court found that whatever ambiguity may surround the term “processing system,” the claims could still be understood with reasonable certainty.

Finally, although the parties had agreed that “processing system” is not a means-plus-function term, Cox argued that the term was indefinite because it was only described in functional terms. The Federal Circuit reiterated that “claims are not per se indefinite merely because they contain functional language.” In this case, the Court found that the functional descriptions actually bolstered the term’s definiteness, because it clarified which operations the “processing system” must undertake.

Regardless of whether the Federal Circuit’s comparative omission analysis for definiteness is adopted by future courts, this case could be read to suggest that definiteness challenges based on terms that are not tied the point of novelty are less likely to succeed. It also provides good practice pointers that definiteness arguments should not lose sight of the claims as a whole, and that functional descriptions of physical elements can lend definiteness to an otherwise ambiguous term.