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Determining Patentable Subject Matter in the United States and Canada

April 10, 2012

As reported in our March 21, 2012, Spring Alert, the United States Supreme Court recently held in Prometheus v. Mayo that certain personalized medicine claims were directed to laws of nature and were thus unpatentable despite containing both an administering step and a determining step. The decision has raised concern amongst biotechnology patent seekers and holders especially in the area of diagnostic methods.

The Prometheus claims were based on the identification of particular ranges of metabolites that are associated with drug efficacy and toxicity. Prior to this, it was known that the levels of the metabolites were correlated with efficacy and toxicity. However, the particular ranges recited in the claims were not known to correlate. The Court was asked to consider whether the method claims contained statutory subject matter although many commentators think the issue of inventiveness appeared more relevant. The Court, in rejecting the claims, pointed to the fact that the claimed steps were conventional, well-known and routine. In the decision, the Court iterated a test for patent eligibility that could have broad applicability. For example, the Supreme Court noted that:

  While it takes a human action (the administration of a thiopurine drug) to trigger a manifestation of this relation in a particular person, the relation itself exists in principle apart from any human action. The relation is a consequence of the ways in which thiopurine compounds are metabolized by the body – entirely natural processes. And so a patent that simply describes that relation sets forth a natural law.

Such a strict analysis could have serious implications for the biotechnology industry as many biotechnological inventions relate to a natural process in one way or another. The Court was particularly concerned with whether the claims transformed unpatentable natural laws into patent-eligible applications of those laws. The Supreme Court did go on to concede that new drug claims and new uses of existing drugs would be acceptable.

Since the Supreme Court did not provide much guidance on what is sufficient to transform a law of nature into an application of a law of nature, we must await the interpretation of this case by the lower courts. There is hope that the lower courts will particularize this decision to its set of facts: that doctors had already been administering patients with thiopurine for the treatment of the particular disease and that the levels of metabolites had already been detected after such treatment. But what would have happened if the case that went on appeal had better facts? For example, if a particular polymorphism had been identified to correlate to a specific disease, would the determining step be inventive as it would be detecting the presence of the polymorphism in a particular population of patients, a population that was unknown before this correlation was identified, even though routine molecular biology techniques could be used for such detection? In Prometheus, the claim was found to involve steps that involve well-understood, routine, conventional activity previously engaged in by researchers in the field. In the example given here, the conventional activity of detecting the presence of the polymorphism would not have been previously engaged in by researchers in the field of that particular disease.

The biotechnology community won’t need to wait long to find out how far the reach of the Prometheus decision may extend because on Monday, March 26, 2012, the United States Supreme Court asked the Federal Circuit to revisit its decision in the Myriad Case. (For a review on the Myriad Case, please see Appeal Court Confirms that Isolated DNA is Patentable in the U.S.)

The patent at issue in Myriad contained claims to genes, diagnostic methods and screening assays. The Federal Circuit previously held that claims to isolated genes were patentable because the isolated DNA is “markedly different” from that which exists in nature, in particular, the isolated DNA is a distinct chemical entity which has been cleaved or synthesized to consist of a fraction of a naturally occurring DNA molecule.

If the Prometheus decision is given a broad interpretation by the Federal Circuit, some are concerned that since routine, conventional activity is typically engaged in when isolating a DNA sequence, the Prometheus decision could have adverse consequences on claims to genes per se. In particular, some fear that the Federal Circuit will find that the gene sequence is just a product of nature and the additional steps of isolating and purifying the DNA molecule do not transform it into a patentable invention.

The Myriad case also contained diagnostic method and screening assay claims. The Federal Circuit previously held the screening assay claims patentable but found against the diagnostic method claims because the claims used terms such as “analyzing” and “comparing” for identifying the presence of the breast cancer mutations. In particular, the Court held that such steps could be conducting solely in the mind and thus were not patentable. After Myriad, it was thought that adding steps such as “determining” or ‘”administering” would be sufficient to transform the claim, however, Prometheus has made it clear that more may be needed.

There is no doubt that the biotechnology community will be on pins and needles awaiting the Federal Circuit’s review of its Myriad decision, hoping that it will view Prometheus narrowly, relating to its particular facts, where the additional steps were clearly known and used in the prior art.

In Canada, patent eligible subject matter has also been a hot topic of late. In November 2011, the Federal Court of Appeal released its decision in, holding that claims should be given a purposive construction when considering patentable subject matter. On the heels of the decision, the Canadian Intellectual Property Office (CIPO) released three draft practice notices on April 2, 2012, for a 30-day consultation period, including a notice related to Office Practice Respecting Claims to Diagnostic Methods and Medical Uses.

Unfortunately, the CIPO notice puts an emphasis on the “inventive concept” of the claims, a concept that arguably has no basis in Canadian law. This new approach would allow Examiners to ignore portions of a claim that the Examiner deems not to contribute to the inventive concept. The draft notice relating to diagnostic methods cautions:

  If, following a purposive construction of the claim, it is determined that the inventive concept includes at least one step of physically acquiring data from an analyte then the inventive concept is statutory. The mere fact that a physical step is identified in a diagnostic method as an essential element for the purposes of determining the scope of the monopoly does not necessarily mean that the subject matter defined by the claim is statutory subject matter. Where a known analyte had been previously assessed using the same or obviously equivalent analytical techniques to those in the claim, the inventive concept of the claim may be limited to the significance, understanding or interpretation of the acquired data. An inventive concept limited to the discovery of the significance of the acquired data, or to its understanding or interpretation, is considered to be abstract or a mental method, and thus not statutory.

This CIPO draft notice seems to be reminiscent of the United States Prometheus decision, essentially ignoring the purposive construction of the claims as a whole, and instead determining whether the additional steps provide an inventive contribution.

The CIPO draft notice does not stop at diagnostic method claims. It goes on to assess the patentability of medical uses, categorically dismissing dosage regime claims despite the fact that there is conflicting case law on the status of such claims.

The CIPO practice notice is a draft and we believe that there will be a huge push back from the biotechnology industry as well as from the patent bar, which hopefully will be able to convince CIPO that this notice goes far beyond the current state of law in Canada.

Unfortunately, the Prometheus decision and the recent draft CIPO practice notices appear to be signalling a new era for patenting of biotechnology in both the United States and Canada. As such, patentees should ensure that applications include as many different types of claims as possible, such as methods, kits, compositions, and methods of medical treatment/uses. In addition, patentees should consider various fall-back dependent claims that provide particular steps with an emphasis on anything that is considered non-conventional in order to keep options open until the ramifications of the Prometheus and Amazon decisions are known. Patentees are encouraged to contact us for further advice.

Melanie Szweras, B.Sc., Ph.D. (Genetics), LL.B., is a partner in Bereskin & Parr LLP's Biotechnology & Pharmaceutical practice group. She can be reached in Toronto at 416.957.1678 or

Micheline Gravelle, B.Sc., M.Sc. (Immunology), is a partner and the leader of Bereskin & Parr LLP's Biotechnology & Pharmaceutical practice group. She can be reached in Toronto at 416.957.1682 or

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Melanie Szweras Melanie Szweras
B.Sc., Ph.D. (Genetics), LL.B.
416.957.1678  email Melanie Szweras
Micheline Gravelle Micheline Gravelle
B.Sc., M.Sc. (Immunology)
416.957.1682  email Micheline Gravelle