Diagnostic Patent Take-Home Lessons from the Recent Federal Circuit Athena Case

February 8, 2019


Recently, the U.S Court of Appeals for the Federal Circuit issued a split panel decision1 in Athena.2 Athena, which examined the patent subject matter eligibility of four claims in one issued patent, upheld a district court's determination that the claims, drawn to diagnostic methods—and containing a correlation with specifically enumerated physical steps—were not patent subject matter eligible.

Supreme Court, Federal Circuit, district court, and Patent Trial and Appeal Board decisions, arising from applying the two-step patent subject matter eligibility test articulated in Alice,3 are creating an evolving framework for determining the patent subject matter eligibility of diagnostic method patent claims. There have been a number of publications in the industry asserting that the Athena decision represents a major change in the patent subject matter eligibility law. However, Athena is largely consistent with other recent case law.


In Athena, a Federal Circuit three-judge panel considered, on appeal from the district court, the patent subject matter eligibility of claims 6-9 of U.S. Pat. No. 7,267,820 (the '820 patent). The basis for filing and obtaining the '820 patent was the discovery that 20 percent of Myasthenia gravis (MG)4 patients make auto-antibodies to a protein5 known as MuSK. The detection of the presence of these auto-antibodies is correlated with the presence of MG.

The claims at issue divided roughly into two claim types. The first involved contacting a labeled MuSK protein or epitope (e.g., with radioactive iodine), and contacting the labeled protein with a patient's bodily fluid. If an auto-antibody was present in the bodily fluid, the auto-antibody bound to the labeled protein or labeled epitope to form a complex. The complex was then immunoprecipitated, isolated, and detected. Detection of the complex correlates with the patient having MG.

The second claim type involved detecting a complex of unlabeled MuSK (or a MuSK epitope) and bound auto-antibody using an enzyme-linked immunosorbent assay (ELISA). Again, detection of the complex correlates with the patient having MG.

In examining the claims at issue, the Federal Circuit initially applied the first prong of the Alice patent subject matter eligibility test: Are the claims "directed to" a judicial exception to patent subject matter eligibility (in this case, a law of nature)?6 The Athena court affirmed that the claims were directed to a law of nature, i.e. "the correlation between the presence of naturally occurring MuSK auto-antibodies in the [patient's] bodily fluid and MuSK-related neurological diseases like MG."7

Having determined that the Alice test's first prong was satisfied, the Federal Circuit considered the Alice test's second prong: "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."8

Of particular relevance to the Federal Circuit's analysis was the fact that the physical techniques recited in the claims (e.g., iodination, immunoprecipitation, and ELISA) were admitted in the patent specification as being "standard techniques in the art."9 The Federal Circuit therefore concluded that the '820 patent "thus describes the claimed invention principally as a discovery of a natural law, not as an improvement of the underlying immunoassay technology. Consistent with the specification, the claims are directed to that law."10

Put another way, the Federal Circuit concluded that the "claims here are directed to a natural law because they recite only the natural law together with standard techniques for observing it."11 Because natural laws are judicially created exceptions to patent subject matter eligibility, the Federal Circuit affirmed the district court's determination that the claims were not patent subject matter eligible.12

Athena offered other arguments for patentability, including that the claims did not "preempt" the natural law, and that the presence of a "man-made molecule" (e.g., the radiolabeled MuSK) in itself, should render the claims patent subject matter eligible. The Federal Circuit disagreed, noting absolute preemption is not required under Supreme Court precedent and explained that a synthetic molecule is nevertheless conventional if it simply involves conventional labeling to implement a natural law.

The Dissent

In a strongly worded dissent, Judge Newman criticized the holding, arguing among other things, that: 1) the claims are for a multi-step method of diagnosis, not a law of nature;13 2) "the new and improved technique, for producing a tangible and useful result, falls squarely outside of those categories of inventions that are 'directed to' patent-ineligible concepts;"14 and 3) that by separating the natural law from the physical claim steps, the majority had failed to consider the claim as a whole, as required by previous Supreme Court holdings.15 Points one and three have significant overlap. Judge Newman also cited amicus curiae for the proposition that public interest is poorly served by disincentivizing research and development of new diagnostic tests.16 Significantly, the majority did not disagree with Judge Newman's policy concerns, but concluded that "[o]ur precedent leaves no room for a different outcome here."17

Judge Newman makes strong points in her dissent. It remains to be seen if certiorari will be sought, and if sought, will be granted.


There are several points worth emphasizing arising from Athena.

  1. The application that the '820 patent issued from was drafted and filed before cases such as Mayo and Alice. Accordingly, the drafters did not have the benefit of drafting with these and similar cases in mind.
  2. The law of patent subject matter eligibility has not changed as a result of Athena. For example, the subject matter eligibility statute wording remains the same, the Alice test is still applied, and the Supreme Court's judicial exceptions are unchanged.
  3. Admissions, if made at all in a patent application, should be carefully considered for their potential impact on prosecution and litigation.
  4. Would-be patentees should consider the potential benefits of highlighting aspects of their diagnostic method(s) that are new and improved and that are not conventional or routine, and including these aspects in diagnostic method patent claims.
  5. Whether it reflects a small evolutionary change in the Alice test, or is simply evidence of panel-variability, the split panel decision raises an interesting question of what it means to "consider a claim as a whole" when applying the Alice test. The case should be monitored because certiorari may be sought and could be granted.
  6. Non-preemption arguments may not carry the day when arguing for patent subject matter eligibility.
  7. Similarly, the presence of a "man-made molecule," without more, may not confer patent subject matter eligibility.
  8. Finally, and perhaps most importantly, the Athena decision does not close the door on patenting diagnostic methods.

For questions regarding diagnostic method patents, patent subject matter eligibility, or any patent related considerations, please contact Vern Norviel, Richard Torczon, Lora Green, or any member of the patents and innovations practice at Wilson Sonsini Goodrich & Rosati.

Charles Andres and David Knapp contributed to the preparation of this WSGR alert.

1 Judge Newman strongly dissented in the case.
2 Athena Diagnostics, Inc. v. Mayo Collaborative Services, LLC, No. 2017-2508 (Fed. Cir. Feb. 6, 2019); available at:
3 Alice Corp. v. CLS Bank International, 573 U.S. 208 (2014).
4 MG is an auto-neurological disease characterized by muscle weakness, drooping eyelids, and double vision.
5 The MuSK protein is an enzyme known as a tyrosine kinase.
6 Athena, slip op. at 8.
7 Id. at 9-10 (Emphasis added).
8 Id. at 9 (Emphasis added).
9 Id. at 12.
10 Id. at 12-13.
11 Id. at 13.
12 Id. at 22.
13 Dissent at 2.
14 Id. at 1, quoting 827 F.3d 1042, 1050 (Fed. Cir. 2016).
15 Id. at 4-5 and 8-9.
16 Id. at 12.
17 Id. at 17.