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New Patent Examination Guidance in Canada for Evaluating Medical Diagnostic Methods: Will Canada’s Application Be More Flexible than the U.S.?

Patentable Subject Matter in Canada

In Canada, patentable subject matter is embodied in section 2 of the Canadian Patent Act (Patent Act) which defines an invention as “any new and useful art, process, machine, manufacture or composition of matter, or any new and useful improvement in any art, process, machine, manufacture or composition of matter”. While section 2 is broad, not all inventions can be patented. Specifically, scientific principles, abstract theorems, methods of medical treatment and surgery, higher life forms and forms of energy (e.g., such as electromagnetic and acoustic signals, regions of the electromagnetic spectrum, electric currents, and explosions) are examples of some of the inventions that do not constitute patentable subject matter in Canada.

Subject Matter Eligibility of Medical Diagnostic Methods

On June 29, 2015, the Canadian Intellectual Property Office (CIPO) issued a guidance document for patent examiners (Notice) examining patent applications claiming medical diagnostic methods. The Notice defines a “diagnostic method” as a sequence of steps to be followed to extract diagnostic meaning from data which often comprises steps to:

  1. Acquire data about an analyte (such as identifying, detecting, measuring, etc. the presence or quantity of X in a sample); and

  2. Analyze the significance of the acquired data (such as the presence, increase/decrease of the quantity, etc. of X correlates to condition Y)

The Notice defines “analyte” broadly to include a chemical substance or a biomarker that is the subject of analysis.

A determination of whether a diagnostic method claim is directed to patentable subject matter is made based on the essential elements as determined through a purposive construction of the claim. A proper purposive construction is a two-step analysis requiring an Examiner to identify: (1) the problem the inventors set out to solve; and (2) the solution disclosed.

Problem to be Solved

The Notice states that the identification of the problem to be solved is guided by the specification as well as the Examiner’s understanding of the common general knowledge in the art (but not by reference to the closest prior art). The Notice reminds Examiners that an application may describe more than one problem to be solved but states that for diagnostic methods, it may be appropriate for Examiners to consider that an inventor is looking to solve a “data acquisition problem” and/or a “data analysis problem”.  The Notice provides the following examples of factors recited in a description that may suggest the existence of a “data acquisition problem” or “data analysis problem”:

  1. Factors indicating a possible “data acquisition problem”: (a) a disclosure of a non-common general knowledge analyte and method of identifying or quantifying the analyte; (b) explicit statements that a specific problem or solution relates to how to identify or quantify a particular analyte; (c) a significant level of detail devoted to describing the technical details of how data about a particular analysis is acquired; and/or (d) an emphasis on the challenges or deficiencies of prior means to identify or quantify a particular analyte.

  2. Factors indicating a possible “data analysis problem”: (a) explicit statements suggesting the problem to be solved is a “data analysis problem” or something other than a “data acquisition problem”; (b) placing an emphasis on the discovery of an allegedly new correlation between a condition and an analyte that is common general knowledge with a relative absence of technical details pertaining how to acquire the data about the analyte; (c) indicators or explicit statements that, in order to acquire data about a particular analyte, it is common general knowledge to apply the means contemplated by the application; and/or (d) an absence of an explicit indication in the application that any practical problems were overcome relating to how to acquire data about an analyte that is common general knowledge.


The solution is the element or set of elements essential to the resolution of the problem. The choice of a solution should be guided by the description, selecting the solution given the greatest emphasis by the inventors.

For a “data acquisition problem”, the solution can be provided by those elements that provide a means to acquire data about an analyte. The means by which is the data is acquired can be represented by either a single or multiple steps recited in the claim. Examples of elements relating to data acquisition that may be represented by steps include: (a) detecting protein X in a subject sample; (b) determining the expression levels of genes A, B, and C; (c) contacting a urine sample with antibody A and determining the optical density; or (d) incubating a sample with a nucleic acid problem consisting of SEQ ID NO:1 and detecting hybridization between the probe and target sequence Z.

For a “data analysis problem”, the solution can be provided by those elements that relate to the analysis of acquired data for the purposes of providing diagnostic meaning. Examples of elements relating to data analysis that may be represented by steps include: (a) relating the presence of protein X from said test sample to a diagnosis of whether the test sample is from a subject suffering from disease Y; (b) comparing the expression levels of genes A, B and C to a control standard, wherein a decrease in the levels as compared to the control is indicative of disease Y; or (c) wherein hybridization of the probe to a target is indicative of the presence of disease Y.

Determining the Essential Elements of a Claim

Once the problem and solution have been identified, the meaning of various terms used in the claims are construed and a determination made of whether elements recited in the claims are essential (meaning the element provides a solution to the problem) or non-essential. Next, considering the elements required to solve the problem, the Examiner analyzes the claims to determine whether: (a) those elements or set of elements that are essential to the solution; and (b) all of the elements required for providing the solution are encompassed by the claim.

A claim that appears to lack an essential element may be found defective for overbreadth (namely, lack of support) and/or lack of utility.

Additionally, the Notice states:

Recognizing that how data is analyzed or interpreted in a diagnostic method generally has no material effect on how the data needs to be physically acquired (and vice versa), the data acquisition elements and data analysis elements in the diagnostic method claim likely have a relationship reflecting an aggregation rather than a combination.

Where a ‘data acquisition problem’ exists, the essential element or set of essential elements providing the solution is the means to acquire data about the analyte. If the identified problem does not relate to data acquisition then it will presumably relate instead to a ‘data analysis problem’. Where this is the case, the essential elements will include steps relating to the mental analysis and/or intellectual significance of the data and will likely not include any steps to acquire the data since the way the data is acquired does not change the nature of the solution.

Determining whether a claim defines statutory subject-matter

The Notice states that when a physical step of data acquisition is identified as an essential element of a construed claim, then the claimed subject matter will likely be deemed to be statutory. However, in contrast, the notice further states:

…a diagnostic method claim construed as consisting solely of essential elements that are disembodied (e.g., mental process, lacking physicality, no practical application, etc.) will be identified as defective for not complying with section 2 of the Patent Act. This would generally apply to situations where the identified solution is only provided by an element or set of elements associated with the analysis or significance of the acquired data (e.g., the correlation).

What happens now?

CIPO advised Applicants that examination of patent applications claiming medical diagnostic methods had been delayed pending release of this Notice. Now that the Notice has been published, Applicants should start receiving Office Actions possibly rejecting medical diagnostic claims for lack of patentable subject matter. Because the Notice does not have the force of law, it will be interesting to see how strictly it is applied by Examiners and, if any final Office Actions are received, whether any Applicants appeal to the Federal Court challenging such application.

It will be interesting for Applicants to see how the analysis of subject matter eligibility of claims to medical diagnostic methods will compare in Canada versus the U.S. As many readers will recall, on December 16, 2014, the U.S. Patent and Trademark Office (USPTO) issued the 2014 Interim Guidance on Patent Subject Matter Eligibility (Interim Guidance) which superseded the March 2014 Interim Guidance for natural phenomenon and laws of nature and supplemented the June 2014 Interim Guidance for abstract ideas. The below flow chart summarizes the subject matter eligibility analysis used by the USPTO for evaluating whether a claim is drawn to patent eligible subject matter.


Time will tell whether CIPO’s application of the Notice will allow Applicants to obtain broader claims to medical diagnostic methods than currently possible in the U.S.

©2021 MICHAEL BEST & FRIEDRICH LLPNational Law Review, Volume V, Number 195

About this Author

Lisa Mueller, Michael Best, Patent application Attorney, intellectual property lawyer,
Partner, Industry Group Chair, Life Sciences

Lisa provides strategic counsel on complex patent issues to clients in the pharmaceutical, biopharmaceutical, biotechnology and chemistry sectors. She brings an in-depth knowledge and extensive experience to her work advising clients on patent protection, freedom to operate and invalidity of blockbuster drugs they aim to produce and distribute.

Lisa’s advice on the full spectrum of global intellectual property portfolio management includes patent prosecution, opposition and other post-grant proceedings