Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Patent watch

Diagnostic patents at risk after Federal Circuit decisions

Credit: Stocksnapper/Alamy Stock Photo

Patent claims to diagnostic methods have been endangered in the United States — but not elsewhere in the world — ever since the US Supreme Court handed down its decision in Mayo v. Prometheus Labs in 2013. In the latest example, Genetic Technologies Ltd v. Merial, the Federal Circuit has once again invalidated claims on genetic diagnostic methods, holding that the patent did not involve anything more than a routine application of natural laws.

In the Mayo case, the Court held that medical diagnostic methods comprised laws of nature, and that without 'something more' claims to such methods were not eligible for patenting. The Court's concern was that such claims would unduly pre-empt laws of nature (such as Archimedes' principle or Einstein's E = mc2) and thus a claim must be limited to an application of the natural law. Importantly for how these principles have been developed by the US Patent and Trademark Office and the inferior courts, the Supreme Court also precluded from this ineluctable 'something more' methods that were “routine, well-understood or conventional.” This outcome thus precluded the new use of an old method for making a medical diagnosis.

As a result, claims to medical diagnostic methods have been more difficult to obtain and defend. Particularly with regard to claims granted before these cases were decided (and thus missing any disclosure that could ameliorate the negative effects of these decisions), there have been several cases where such claims have been invalidated. Three are of primary importance; in each case the Court of Appeals for the Federal Circuit (the appellate court that has jurisdiction over all cases in the United States arising under the patent laws) has affirmed a lower court's decision that the claims are ineligible for patenting under Supreme Court precedent. These cases are In re BRCA1- and BRCA2-based Hereditary Cancer Test Patent Litigation (Myriad III; 2014), Ariosa v. Sequenom (2015) and Genetic Technologies Ltd v. Merial (2016); each case extends the reach of the Mayo decision for invalidating genetic diagnostic method claims.

In the Myriad III case, the Federal Circuit held that Myriad's claims — which recited the specific mutations, primers and methods for detecting breast cancer-related mutations in the BRCA1 and BRCA2 genes — were invalid for reciting a law of nature (the association of specific BRCA mutations with cancer predisposition) that was detected by “routine, well-understood and conventional” methods (PCR, sequencing and hybridization). This was followed by the Ariosa case, which involved claims to a blood test for detecting paternal DNA amongst cell-free fetal DNA (cffDNA) in maternal blood. The invention provided a substitute for more invasive tests, such as amniocentesis and chorionic vilus sampling that put the life and health of the fetus and mother at risk, and was developed using blood fractions that had been routinely discarded before the inventor recognized that cffDNA was in those fractions. Nevertheless, the district court invalidated these claims for reciting patent-ineligible subject matter and the Federal Circuit affirmed that decision. The rationale was the same as in Myriad III: the existence of cffDNA in maternal blood was a natural phenomenon, and the claim recited only conventional methods for detecting it. This case has been the subject of opinions by several Federal Circuit judges, in which they state that the decision was incorrect but that the court's hands were tied by “the sweeping language in the Supreme Court's Mayo opinion” (see Further information). Sequenom has petitioned the Supreme Court for review, but the Court's decision to review is at least 4 months away, and if the petition is granted a decision will not be forthcoming for at least 6–10 months after that.

The most recent case, Genetic Technologies Ltd, is important not merely because of its holding (indeed, the Federal Circuit used the same logic in affirming this decision) but because the district court dismissed the case before any evidence could be adduced or the claims construed, on the grounds that the patentee had not stated a claim that the court could recognize, because the claims were not patent eligible as a matter of law. In addition, the court's opinion was frankly based on the Sequenom decision, thus making diagnostic methods claims per se patent ineligible.

These decisions (and other similar decisions by other district courts in other cases not yet reviewed by the Federal Circuit) make even more imperative some clarification by the Supreme Court of the scope of exclusion from patent eligibility that it believes it created with its Mayo decision. The Court 's concerns with preventing undue pre-emption have created a chill on innovation that has unintentionally hobbled an entire industry, one that is important for the nation's health and economy. Genetic diagnostic testing is just now beginningto reach full flower with explication of the relationships between genetic mutation and human disease that have arisen from genome sequencing efforts. The Court has evinced a greater interest in defining the proper contours of US patent law over the past decade; correcting the judicial overreach occasioned by the Mayo decision is perhaps its most important task.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Kevin Noonan.

Ethics declarations

Competing interests

The author declares no competing financial interests.

Related links

Related links


Federal Circuit opinion on Ariosa v. Sequenom

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Noonan, K. Diagnostic patents at risk after Federal Circuit decisions. Nat Rev Drug Discov 15, 377 (2016).

Download citation

  • Published:

  • Issue Date:

  • DOI:


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing