From The Field

February 12, 2019

In Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 2019 U.S. App. LEXIS 3645 (Fed. Cir. Feb. 6, 2019), the Federal Circuit issued another fractured decision applying 35 U.S.C. Section 101. Athena is the court’s eighth 2-1 decision in the Section 101 arena in the past year-and-a-half.

The inventors of the patent-at-issue in Athena discovered a correlation between the autoimmune disorder myasthenia gravis (MG) and the presence of autoantibodies to a protein called muscle-specific tyrosine kinase (MuSK). The majority (consisting of Judges Lourie and Stoll) held invalid certain claims from the patent that covered methods of diagnosing MG by detecting antibodies to MuSK.

The claims involved the steps of (1) contacting MuSK having an iodinated label with bodily fluid; (2) immunoprecipitating any resulting antibody/MuSK complex; and (3) monitoring for the label on the complex, wherein the label indicates the presence of MG. The patent specification conceded that the iodination and immunoprecipitation steps were both “standard techniques[.]” Because the majority believed that precedent required it to disregard these steps, it held that the claims were invalid: the only step left, i.e., recognizing “the correlation between [ ] naturally occurring MuSK antibodies … and [ ] diseases like MG,” was an ineligible natural law.

Much of the debate in Athena centered on whether the claims are “directed to” a law of nature. The majority found that the claims were comprised of just a natural law and a series of standard techniques for observing it, and that Supreme Court and Federal Circuit precedent teach that such claims are “directed to” a law of nature. By contrast, Judge Newman in dissent argued that the court should not have discounted the conventional or routine steps. Relying on Diamond v. Diehr, Judge Newman stated that “[e]ligibility is determined for the claim considered as a whole, including all its elements and limitations. Claim limitations cannot be discarded when determining eligibility under Section 101[.]”

One issue the majority side-stepped was how to identify the law of nature that is supposedly at stake. The majority stated that the “relevant natural law” was “the correlation between … naturally occurring MuSK antibodies in bodily fluid and … diseases like MG.” In footnote 3, however, the court acknowledged that a different formulation – such as “the binding of MuSK to MuSK antibodies in bodily fluid” – might not qualify as a “natural law.” But, without citation, the court concluded that it “need not resolve that issue[.]” The majority never explained how to decide whether a given claim implicates a natural law or how to “identify what the relevant natural law is.”


On July 3, 2019, the Federal Circuit issued an order denying a request for en banc review in Athena. The order was accompanied by eight separate opinions spanning 86 pages.

Judges Lourie, Hughes, Dyk, and Chen all wrote opinions concurring in the decision to deny en banc review. The concurrences all believed that the Supreme Court’s Mayo decision required the panel decision holding the Athena claims invalid. Judge Chen’s opinion underscored an apparent tension between Mayo and Diamond v. Diehr with respect to whether courts must consider all claim limitations when ruling on eligibility.

Judges Moore, Newman, Stoll, and O’Malley all wrote opinions dissenting from the denial of en banc review. Judges Moore and Stoll emphasized their view that Mayo should not be interpreted to bar all diagnostics patents. Judge O’Malley wrote that the post-Mayo case law has improperly reinstituted the “inventive concept” doctrine that Congress abrogated when it enacted the 1952 Patent Act. According to Judge O’Malley, the 1952 Act dispensed with the “inventive concept” doctrine and focused instead on novelty and obviousness.

Author: Marc J. Pernick