Are diagnostic methods patentable?

Whilst patenting a diagnostic method in the US remains challenging following the infamous decision in Mayo, other jurisdictions have, by contrast, recently confirmed their willingness to recognise the patentability of diagnostic inventions. Across the border in Canada, the Patent Appeal Board recently confirmed that a diagnostic method could be patented provided the method could be construed as including physical means for measuring, and so not related exclusively to mental activity (Re Antibodyshop A/S 2021 CACP 35). In Australia, the Federal Court recently confirmed that the test for the patent eligibility of a diagnostic method is whether the method has economic utility  (Ariosa Diagnostics, Inc v Sequenom, Inc [2021] FCAFC 101).  

Diagnostics

Australia: The exception to patentability of natural products per se does not extend to diagnostic methods

The patentability of diagnostic methods was recently confirmed in Australia, in the case of Ariosa Diagnostics, Inc v Sequenom, Inc [2021] FCAFC 101. The patent in question (AU 727919) related to a method of non-invasive prenatal blood testing (NIPT). Sequenom owns some of the broadest patents in the competitive field of NIPT, and has a patent pool agreement with Illumina. Illumina and Sequenom have joined forces in a global patent battle with other players in the field. In Ariosa  v Sequenom, the patent claimed a method of detecting the presence of foetal DNA in a blood sample from a pregnant woman. Ariosa argued that the claimed methods related to the detection of a naturally occurring product (foetal DNA) and was thus not a patentable invention. 

Elsewhere, the US Court of Appeals for Federal Circuit had found the corresponding Sequenom US diagnostic patent invalid for relating to the "natural phenomena" of maternal blood and its contents (Ariosa v Sequenom). Sequenom were denied permission to appeal to the US Supreme Court (IPKat). However, a similar argument that the patented method related to natural phenomena was rejected by the Court of Appeal in the UK (Illumina v TDL [2019] EWHC 1497, IPKat). 

In Australia, the Federal Court considered the case law on patent eligibility in Australia, including Myriad, which established that patentable subject matter should relate to "something brought about by human action" or an "artificially created state of affairs". However, importantly, the issue in Myriad (as in the corresponding landmark US case), was whether an isolated gene sequence was patentable. The patent in Ariosa v Sequenom, by contrast, related to a method of detection and not a natural product per se. The court determined that the foetal DNA detection method could clearly be said to have economic significance. The patent claims could thus be said to relate to a method with practical utility (NRCD) as opposed to a natural product, and thus did not relate to an exception to patentability. 

Canada: "determining" may be a physical step

Historically, patenting diagnostic methods in Canada was a challenge (IPKat). However, in contrast to the US, recent case law confirms the present willingness of Canada to accept the patentability of diagnostic inventions. Particularly, the recent Patent Appeal Board (PAB) decision in Re Antibodyshop A/S (2021 CACP 35) confirms the approach of the Canadian patent office towards diagnostic methods following the landmark decision of the Federal Court in Choueifaty v Canada (Attorney General), 2020 FC 837 on the related issue of the patentability of computer implemented methods. 

The Canadian Patent Act stipulates that "No patent shall be granted for any mere scientific principle or abstract theorem" (subsection 27(8), Patents Act). Following Choueifaty, the Canadian Intellectual Property Office (CIPO) issued guidance that altered the established practice of the patent office to diagnostic methods, and particularly their exclusion from patentability under subsection 27(8) (PN2020-04). The guidance stated that a diagnostic method claim that includes "physical means for testing or for identifying, detecting, measuring, etc", should not be prohibited from patentability. Methods involving entirely mental steps, by contrast, are not considered patentable according to the guidance (PN2020-04). 

In the recent case, the patent application (CA 2,591,113) related to a method of determining the likelihood of kidney disease following a renal insult, comprising monitoring a biomarker (NGAL) in the blood. Prior to the issue of the new guidance, the patent office rejected the claims, finding that all of the elements of the claimed method related to abstract ideas. 

The applicant submitted that according to the new guidance the claimed invention should not be deemed to fall under the subsection 27(8) exclusion. Particularly, the claim included the physical step of "determining the concentration of NGAL". The Examiner disagreed, arguing that "determining" the concentration of NGAL was not necessarily limited to a physical step of measuring, but included entirely mental steps, such a reading a report containing a value. 

The Patent Appeal Board (PAB), by contrast, found that the term "measuring" should be purposively construed in view of the description as requiring a physical measuring step. In other words, the term "determining" used in the claims, effectively meant "measuring". The claims were thus found not to relate to non-patentable subject matter. The decision by the PAB thus confirms the new more lenient approach to diagnostic patents in Canada. 

Final thoughts

In Europe, diagnostic cases are patentable provided that the method does not relate to a method practised on the human or animal body (Article 53(c) EPC). In other words, a diagnostic method carried out in vitro on an isolated sample is not considered an exception to patentability (EPO Guidelines for Examination, G-II-4.2.1.3). The recent cases in Canada and Australia confirm that these jurisdictions are broadly aligned with Europe on the patentability of diagnostic methods, albeit with the application of different legal tests. Ever since Mayo, the US has been the outlying jurisdiction with regards to diagnostic methods. However, the recent decisions in Australia and Canada also highlight that careful patent drafting of diagnostic cases is required if the varying patent eligibility criteria applied by different jurisdictions are to be satisfied.