Diagnostics update: Subject matter eligibility in Canada

By Wendy Lamson
février 22, 2021

Helping you streamline allowance

Personalised medicine shows tremendous promise in revolutionizing the way we diagnose and treat disease.  However, in recent years securing patents in this rapidly evolving field has proven challenging.  Such technology is often heavily reliant on computer-implemented data analytics to decipher a patient’s unique molecular make-up, and inventions in the computer-implemented arts are especially prone to subject matter eligibility rejections.  Claims containing computer computation steps are often viewed by patent examiners as disembodied ideas and thus deemed ineligible for patenting under section 2 or 27(8) of the Patent Act.  Nonetheless, the recent Yves Choueifaty v. Attorney General of Canada [2020 FC 837] decision provide a glimmer of hope for patent applicants seeking to secure patent protection in this emerging field.

To provide historical context, previous Practice Notice 2015-2 issued by the Canadian Intellectual Property Office (CIPO) instructed Canadian patent examiners to first determine those elements of a claim which are essential by analyzing the problem solved by the invention.  The problem was identified as either a “data analysis problem” or a “data acquisition problem” depending on what was written in the patent specification.  A data analysis problem was characterized as one describing the need for a correlation between a condition (e.g., a disease) and an analyte and a data acquisition problem was one that related to a problem concerning data that was acquired about an analyte.  The essential elements of the claim were identified as those that solved either the data analysis problem or the data acquisition problem.  The legal challenge with such approach was that the non-essential elements, namely those determined as not providing a solution to one of these problems, were disregarded from further analysis.  The result was that claims reciting various physical features were being disregarded in patent eligibility assessments by examiners.  Interestingly, there was no legal precedent in the case law to support such an approach to claim construction.

The essential elements of the claim construed as per the Practice Notice 2015-02 were then analyzed to determine if they were directed to statutory subject matter.  As indicated in Practice Notice 2015-02, “[w]here a physical step of data acquisition is identified as an essential element of the construed claim, the claimed subject-matter will likely be statutory”.  However, if the essential elements of a claim were characterized as a data analysis problem and solution, (e.g., a correlation) then the claim was generally rejected by the Examiner as being directed to non-statutory subject matter.  This is because the correlation was seen as a disembodied mental process.  Many personalized medicine patent applications were falling afoul of CIPO’s examination policy and repeatedly rejected for failure to recite patent-eligible subject matter.

Choueifaty rejected a “problem-solution” approach to claim construction that was applied by patent examiners and found claims directed to a computer-implemented invention patentable.  A new Practice Notice titled “Patentable Subject -Matter under the Patent Act” was issued after Choueifaty in 2020 and is generally a positive for patent applicants seeking protection of medical diagnostic subject matter.

The new Notice sets out the current understanding of the Patent Office regarding the legal principles applicable in determining whether the subject-matter defined by a claim is patent eligible subject-matter and specifically states that the “contribution of a claim” and “problem solution” approach in the identification of essential elements during purposive construction should no longer be applied.

With regard to medical diagnostic claims, the new Practice Notice states that:

a diagnostic method claim that defines a combination of elements that cooperate together so as to form a single actual invention that includes physical means for testing or for identifying, detecting, measuring, etc. the presence or quantity of an analyte in a sample would be considered to be patentable subject-matter and not to be prohibited under subsection 27(8) of the Patent Act.[1]

The Notice also provides an example of a diagnostic claim that is eligible and another that is ineligible:

  1. A method of diagnosing whether a human subject is at risk for developing cancer, comprising:
    1. measuring the level of X in a biological sample from the subject; and
    2. comparing said level to the level of a non-cancerous reference sample, wherein an increase in the level of X relative to said reference indicates the subject is at risk for cancer.
  2. A method of diagnosing whether a human subject is at risk for developing cancer, comprising:
    1. receiving a report summarizing the level of X in a sample from the subject; and
    2. comparing said level to the level of a non-cancerous reference sample, wherein an increase in the level of X relative to said reference indicates the subject is at risk for cancer.

The Notice states that claim 1 is subject matter eligible for the following reason:

Recognizing that step a) is directed to physically measuring the level of X in the sample, this satisfies the physicality requirement and makes the subject-matter of the claim patentable subject-matter.[2]

Claim 2 above is considered ineligible since, “[u]nlike claim 1, data about the level of X is not provided by an element that physically measures the level”.  This suggests that providing a step having a physical existence or that manifests a discernable physical effect or change is sufficient to render the claim subject matter eligible.

Of course, patent prosecution is highly fact-dependent and often complex in the unpredictable arts such as biotechnology.  Consequently, the above discussion should not be taken as legal advice.  We will be happy to assist you with legal advice tailored to your unique facts.

The foregoing information provides only an overview. Specific legal advice should be obtained. If you have any questions, please reach out to Wendy Lamson, Partner and Patent Agent in the Intellectual Property Law Group at Perley-Robertson, Hill & McDougall. She can be contacted at 613.566.2748 or [email protected].


[1] See Canadian Intellectual Property office (CIPO) Practice Notice “Patentable Subject-Matter under the Patent Act”, 2020, under “Medical diagnostic methods”, third paragraph, available at https://www.ic.gc.ca/eic/site/cipointernet-internetopic.nsf/eng/wr04860.html

[2] Ibid, “Examples of Patentable Subject-Matter Analysis” under “Diagnostic Method Example”.


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