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Article: August 2019: Life Sciences Litigation Update

August 29, 2019
Business Litigation Reports

Federal Circuit Holds Diagnostic Method Claims Patent Ineligible While Acknowledging Public Policy Implications.  Patents claiming diagnostic methods continue to face patent ineligibility challenges under 35 U.S.C. § 101.  Earlier this year, in Athena Diagnostics, Inc. v. Mayo Collaborative Services, LLC, 915 F.3d 743 (Fed. Cir. 2019), the Court of Appeals for the Federal Circuit affirmed the dismissal of a patent infringement complaint pursuant to Federal Rule of Civil Procedure 12(b)(6) on the ground of subject matter ineligibility.  Athena is one of several decisions by the Federal Circuit concerning the patentability of diagnostic method claims following Mayo Collaborative Services v. Prometheus Laboratories, Inc., in which the Supreme Court held that claims to a diagnostic method based on a “law of nature,” i.e., correlations between thiopurine metabolite levels in the blood and the toxicity and efficacy of thiopurine drugs, were invalid under Section 101.  566 U.S. 66, 77 (2012).

            The patent in Athena claimed methods for diagnosing neurological disorders such as myasthenia gravis (“MG”), an autoimmune disease characterized by muscle weakness, drooping eyelids, double vision, and slurred speech.  915 F.3d at 747.  The inventors discovered the association between MG and certain antibodies in the human body that bind to a protein called muscle-specific tyrosine kinase (“MuSK”).  Id.  The claims at issue recited methods for diagnosing a MuSK-related disorder such as MG comprising three steps:  (1) “contacting” a radioactively-labeled MuSK protein with bodily fluid (if MuSK antibodies are present in the fluid, they will bind to the labeled MuSK); (2) “immunoprecipitating” any antibody/MuSK complex from the bodily fluid, i.e., isolating the complex by adding a secondary antibody that specifically binds to MuSK antibodies; and (3) “monitoring” for the radioactive label, wherein the label’s presence indicates that a person has the disorder.  Id.  According to the patent specification, the immunoassay techniques of adding a radioactive label to a protein and immunoprecipitation were known at the time of invention.  Id. at 748.

            Athena, the exclusive licensee of the patent-in-suit, marketed a diagnostic test that evaluated the presence of MuSK antibodies and accused Mayo’s competing diagnostic tests of infringement.  Id. at 746.  Mayo moved to dismiss Athena’s complaint under Rule 12(b)(6) on the ground that the patent claims were invalid under Section 101.  Id.  The District Court granted the motion, concluding that the claims were directed to a law of nature and lacked an inventive concept because the recited steps involved only standard techniques in the art.  Id. at 748.

            The Federal Circuit agreed.  In its decision, the majority reiterated the two-part test for subject matter eligibility established by the Supreme Court in Mayo and Alice Corp. v. CLS Bank International, 573 U.S. 208 (2014).  First, a court must determine whether a claim, when viewed as a whole, is “directed to” an “implicit exception” to eligibility under Section 101, such as “laws of nature, natural phenomena, and abstract ideas.”  Athena, 915 F.3d at 749.  If the claim is directed to a law of nature, for example, then under step two, the court determines “whether the limitations of the claim apart from the law of nature, considered individually and as an ordered combination, ‘transform the nature of the claim into a patent-eligible application.’”  Id. (quoting Alice, 573 U.S. at 217).

            Applying the Mayo/Alice test, the Athena majority determined that under step one, the diagnostic method claims were directed to a law of nature – namely, the correlation between the presence of naturally-occurring MuSK antibodies and MuSK-related diseases.  Id. at 750.  The majority concluded that the claims, similar to other diagnostic method claims it held ineligible under Section 101 in other decisions since Mayo, were “directed to a natural law because the claimed advance was only in the discovery of a natural law, and that the additional recited steps only apply conventional techniques to detect that natural law.”  Id. at 751.  The majority also noted that the specification described the invention “principally as a discovery of a natural law” and “not as an improvement in the underlying immunoassay technology.”  Id. 

            In addition, the majority made several key observations relevant to analyzing diagnostic method claims under step one of the Mayo/Alice test.  First, the fact that the claims did not preempt other ways of examining the correlation between MuSK antibodies and MuSK-related disorders was insufficient to render the claims patent eligible.  Id. at 752.  Second, the use of a man-made molecule (i.e., a radioactive label) in claimed methods “employing standard techniques to detect or observe a natural law” was also insufficient to render the claims patent eligible.  Id.  Lastly, the majority distinguished claiming a “natural cause of an ailment and well-known means of observing it” from claiming “applications of natural laws” or “new treatment[s] for an ailment, albeit using a natural law.”  Id. at 752-53.  The former claim is ineligible as it “in effect only encompasses the natural law itself,” whereas the latter claim is patent eligible as it “is not claiming the natural law.”  Id.

            With respect to step two of the Mayo/Alice test, the majority concluded that the claims lacked an inventive concept.  The specification described the processes of immunoprecipitation and labeling proteins with a radioactive label, and the overall immunoassay, as conventional techniques.  Id. at 753-54.  Thus, the recited steps not drawn to ineligible subject matter “only require[d] standard techniques to be applied in a standard way.”  Id. at 753.  

            Notably, the majority and dissenting opinions both recognized that public policy favors patentability of diagnostic methods.  In a dissenting opinion, Judge Newman argued that the majority was “enlarg[ing] the inconsistencies” in the Federal Circuit’s decisions on the eligibility of diagnostic methods, and “exacerbat[ing] the judge-made disincentives to development of new diagnostic methods, with no public benefit.”  Id. at 757.  The dissent highlighted the concerns raised in various amici curiae briefs that the unpredictability of patent protection caused by the Court’s decisions inhibit innovation and disincentive the development of new diagnostic procedures.  See id. at 762-64.  In response, the majority agreed that “providing patent protection to novel and non-obvious diagnostic methods would promote the progress of science and useful arts.”  Id. at 753 n.4.  Nevertheless, the majority held the claims at issue were patent ineligible because application of the Mayo/Alice test left “no room for a different outcome.”          

            Following the panel’s decision, Athena filed a petition for rehearing en banc on April 8, 2019, which is currently pending before the Federal Circuit.