The Canadian Patent Office’s new guidance after Choueifaty: Out with the old (problem) and in with the new (problem)

In a recent bulletin, we discussed the Federal Court of Canada’s decision on claims construction in Choueifaty v. Canada (Attorney General), 2020 FC 837 (Choueifaty)1, which rejected the “problem/solution” approach to claims construction that had been routinely applied by the Canadian Intellectual Property Office (CIPO) to reject computer-implemented and medical diagnostic inventions as unpatentable. In the wake of Choueifaty, the CIPO has issued a new guidance document providing the CIPO’s understanding of the law as it applies to the determination of patentable subject-matter2, particularly for computer-implemented inventions, medical diagnostic methods and medical uses.

What you need to know

  • The CIPO has issued a new examination guidance document in view of the Federal Court’s recent decision in Choueifaty, which rejected the CIPO’s previous problem/solution approach to determining essential claim elements. The Court had criticized the previous approach for departing from the Free World Trust test of determining essential claim elements3.
  • While the new guidance document directs that the prior problem/solution approach is no longer to be used, it simultaneously introduces a new problem/solution analysis in determining the “actual invention” claimed despite having already purposely construed the essential elements, and so the new guidance seemingly continues the problem/solution approach and diminishes the significance of Free World Trust in the determination of essential claim elements.
  • The CIPO’s new guidance document appears to suffer from some of the same shortcomings of its previous examination guidance, while introducing new ones, and so despite the Choueifaty decision, applicants may continue to face challenges in pursuing patent applications directed to computer-implemented, medical diagnostic and medical use inventions.

The new guidance principles

The guidance document rejects the previous problem/solution approach and indicates that the determination of whether claimed subject-matter is patentable subject-matter begins with claims construction to determine the essential claim elements, which aligns with both Choueifaty and Free World Trust.

The new guidance departs from Choueifaty, however, with requiring the identification of an “actual invention” after purposively construing the claims to determine the essential claim elements, citing the Federal Court of Appeal in Amazon4. However, instead of looking to the subject-matter of the claims as purposively construed as the “actual invention” as the Amazon Court suggests5, the new guidance document seems to stray from both Choueifaty and Amazon by once again requiring a problem/solution analysis to determine the “actual invention”, stating that “[a]n actual invention may consist of either a single element that provides a solution to a problem or of a combination of elements that cooperate together to provide a solution to a problem” (emphasis added). The CIPO’s view is that “[a]n element of a claimed invention that is identified as essential for establishing the fences of the monopoly under purposive construction is not necessarily part of the actual invention”, and so the CIPO’s new guidance once again provides a problem/solution mechanism for striking essential claim elements.

The instruction to deem essential claim elements as determined by a purposive construction to not form part of an “actual invention” directly contradicts the Supreme Court of Canada’s findings in Free World Trust and the guidance of Choueifaty by divorcing the essential elements test from an “actual invention”, and suggesting that the “actual invention” can be determined without regard for essential elements as purposely construed.

Applying this “actual invention” analysis, the new guidance document provides discussion on specific categories of invention, as described below.

The guidance principles applied

Computer-implemented inventions

With respect to computer-implemented inventions, the guidance document indicates that the determination that a computer element is essential and physical does not end the analysis. According to the CIPO, it remains to be determined “whether the computer cooperates together with other elements of the claimed invention and thus is part of a single actual invention” before determining if the physicality test is met or if it is prohibited as a mere scientific principle or abstract theorem (an explicitly prohibited category of subject-matter under the Canadian Patent Act). However, the guidance document also states that even if the computer cooperates together with other elements of the claimed invention, if the computer is merely used in a well-known manner, or merely processes an algorithm in a well-known manner and the processing of the algorithm on the computer does not solve any problem in the functioning of the computer, the claimed subject-matter would not be considered patentable. Conversely, where running an algorithm on a computer improves the functioning of the computer, the algorithm and computer would be considered by the CIPO to form a single actual invention and patentable subject-matter.

With respect to business methods, the guidance document states that a business method that is not itself patentable subject-matter does not become patentable subject-matter merely by computer implementation. Rather, the guidance requires that an abstract business method cooperate with other claim elements so as to become one of a combination of elements making up an actual invention that meets the Amazon test in order for the claimed combination to comprise patentable subject-matter.

Medical diagnostic methods

The guidance document states that the correlation that is usually present in medical diagnostic claims (correlating, e.g., an analyte to a medical condition) is generally an abstract idea, but that where such an abstract correlation cooperates with and becomes part of a combination of claim elements so as to form a single actual invention, and the combination as a whole satisfies the Amazon test (such as by including “physical means for testing or for identifying, detecting, measuring, etc. the presence or quantity of an analyte in a sample”), then the claimed subject-matter would be patentable. The guidance document clarifies that its comments regarding computer-implemented inventions should be referenced where a computer is involved in the diagnostic method.

Medical uses

Medical use claims are common in Canada as alternatives to methods of medical treatment, which are prohibited under Canadian law. The guidance document states that “an actual invention that has physical existence or manifests a discernible physical effect or change and does not otherwise fall within a jurisprudential exclusion (e.g., methods of medical treatment) would be patentable subject-matter.” The guidance clarifies that where the actual invention includes essential element(s) that comprise an active medical treatment step, or would “restrict, prevent, interfere with, or require the exercise of the professional skill and judgment of a medical professional”, it would fall afoul of the medical treatment method prohibition.

This aspect of the guidance document also clarifies the CIPO’s approach regarding use claims which recite dosages, and states that where the essential element(s) of the actual invention limit the claimed use to a dosage, a dosage range, and/or a dosage regimen, whether the dosage is fixed or part of a range, this is not itself determinative of whether the claim comprises patentable subject-matter. Rather, one must consider whether the actual invention comprises a medical professional’s exercise of professional skill and judgment (such as where they would be required to select from among a range of dosages “where not all dosages in the range will work for all subjects within the treatment group”). Where such professional skill and judgement would be required by the claimed subject-matter, the CIPO’s view is that such cases would comprise prohibited methods of medical treatment.


The CIPO’s revised examination guidance in view of Choueifaty appears to continue the problem/solution approach to examination, by requiring a determination of the “actual invention” in a way that appears contradictory to established case law. This examination approach will likely continue to make it challenging for applicants to pursue patents for computer-implemented, medical diagnostic and medical use inventions, and it will be interesting to see if this examination approach will be challenged in much the same way as the applicant did in Choueifaty against the CIPO’s previous examination approach.




3 Free World Trust v. Électro Santé Inc., [2000] 2 SCR 1024, 2000 SCC 66 [Free World Trust]

4 Canada (Attorney General) v. Inc., 2011 FCA 328 [Amazon]

5 Ibid. at para. 43.

To discuss these issues, please contact the author(s).

This publication is a general discussion of certain legal and related developments and should not be relied upon as legal advice. If you require legal advice, we would be pleased to discuss the issues in this publication with you, in the context of your particular circumstances.

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