Canada: Go Your Own Way: Canadian Patent Office Instructs Examiners To Disregard Supreme Court Of Canada Precedent In Construing Claims

Last Updated: April 10 2017
Article by Ian C. McMillan and Cameron Gale

Materials from a recent "refresher training" for examiners at the Canadian Intellectual Property Office (CIPO) highlight inconsistencies between CIPO's examination practices and Supreme Court precedent. The training reiterates CIPO's position that patent examiners can disregard the substantive principles of purposive claim construction defined by the Supreme Court of Canada in Free World Trust1 and Whirlpool2 when construing the claims of patent applications.

The March 2017 internal training presentation entitled "Refresher Training on Purposive Construction (PCon)"3 summarizes patent office practice regarding purposive claim construction. The presentation states that CIPO does "not apply the Free World Trust (FWT) decision strictly in our examination"4 to determine the essential elements of a claim.

In the 2013 Practice Notice Respecting Purposive Construction PN2013-02 (and in many office actions issued since), CIPO and its examiners rely on the 2008 decision of the Federal Court in Genencor5 to assert that the principles of purposive construction from Free World Trust and Whirlpool apply to court proceedings involving issued patents, but not to the examination of patent applications in CIPO. Genencor held that CIPO, specifically a patent re-examination board, should not be held to the same burden as a court in considering and weighing evidence to construe highly technical terms of a patent. Genencor recognizes that examiners will have less time and resources available to consider a patent application as compared to judges in impeachment proceedings in which experts can be examined and cross-examined.6

In their practice guidelines and the "refresher training" CIPO directs examiners to disregard elements explicitly stated in the claims unless they are "essential to solve the problem" solved by the invention. According to CIPO, it is the examiner, and not the applicant, who identifies this problem. Consider a patent application that is filed for an invention the Applicant has invented to solve a problem and the claims explicitly recite elements that are essential to solve this problem. Then, during examination, the Examiner identifies a different problem solved by the invention and determines that these elements are not essential in solving this different problem. Under CIPO practice, the Examiner is entitled to disregard these elements. The Examiner may then reject the application because the "essential elements" of the claim, as identified by the Examiner, do not define patentable subject matter once the "non-essential elements" are disregarded.

This issue arises commonly with regard to claims rejected for lack of subject matter eligibility. For example, in computer cases, examiners will often characterize the problem solved by the invention such that the computer elements recited in a claim are non-essential and can be disregarded. Once the computer elements are disregarded, the claim is alleged to define an abstract idea or mere scheme.

Rather than perform a purposive construction of the claims, CIPO appears to be instructing its examiners to search for the "spirit" or "substance" of the invention. This approach was specifically rejected in favour of purposive construction by the Supreme Court in Free World Trust7 and, more recently by the Federal Court of Appeal in Amazon.8

What is striking about CIPO's position and its reliance on Genencor is that the Amazon decision of the Federal Court of Appeal, coming years after the Genencor decision and dealing directly with the rejection of claims during examination, states that "the Commissioner's determination of subject matter must be based on a purposive construction of the patent claims." (emphasis added) In Amazon, the Court clearly states that "the jurisprudence of the Supreme Court of Canada, in particular Free World Trust and Whirlpool, requires the Commissioner's identification of the invention to be grounded in a purposive construction of the patent claims."

In Free World Trust, the Supreme Court laid out the principles to be applied when determining whether a claim element can be considered essential or non-essential relying on a series of cases from the United Kingdom, most notably Catnic9 and Improver10. As explained in the 2016 Federal Court decision in Shire Canada Inc. v. Apotex Inc.11, in a purposive construction of the claims, to establish that a claim element is non-essential it must be shown "both (i) that on a purposive construction of the words of the claim it was clearly not intended to be essential, and (ii) that at the date of publication of the patent, the skilled addressees would have appreciated that a particular element could be substituted without affecting the working of the invention."12 Step (i) of this approach is inconsistent with office practice and the training being given to patent examiners - in its "refresher training" CIPO instructs its examiners that "it is not the applicant's intent which determines essentially". This is inconsistent with the test set out by the Court, according to which a claim element will be considered to be essential if it is clear from the wording of the claim that it was intended to be essential.

Recognizing that the examination context in CIPO is different from an impeachment proceeding in a court, CIPO should have the procedural flexibility to limit the time and resources required to determine the meaning of terms in a claim. However, procedural flexibility should not allow CIPO or its examiners to disregard substantive principles of law set out by the Supreme Court of Canada.  

Resolving this inconsistency will likely require further court or legislative intervention. Unfortunately, given the infrequent nature of appeals from decisions from the Patent Appeal Board it may be some time before a court decision is rendered on point. Even then, subsequent to the court decisions in Amazon, it did not take CIPO very long to again adopt office practices seemingly inconsistent with that decision. It seems likely, therefore, that CIPO will continue to "go its own way."


1 Free World Trust v. Électro Santé Inc., [2000] 2 S.C.R. 1024.

2 Whirlpool Corp. v. Camco Inc., [2000] 2 S.C.R. 1067.

3 A copy of the presentation is available at

4 These statements appear to align with CIPO's 2013 Practice Notice Respecting Purposive Construction (PN2013-02) (available at and office practice following PN 2013-02.

5 Genencor International, Inc. v. Canada (Commissioner of Patents) (F.C.), 2008 FC 608, [2009] 1 F.C.R. 361.

6 See Genencor at paragraphs 40 and 70.

7 See Free World Trust at paragraphs 46 and 50.

8 Canada (Attorney General) v., Inc., 2011 FCA 328 at paragraph 43.

9 Catnic Components Ltd. v. Hill & Smith Ltd., [1982] R.P.C. 183.

10 Improver Corp. v. Remington Consumer Products Ltd., [1990] F.S.R. 181 (Pat. Ct.).

11 Shire Canada Inc. v. Apotex Inc., 2016 FC 382.

12 Shire at paragraph 137.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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Ian C. McMillan
Cameron Gale
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