Tuesday, November 10, 2020

The Impact of CIPO’s New Guidance on the Prosecution of Patent Applications Directed to Diagnostic Methods

Tuesday, November 10, 2020


The Federal Court in Choueifaty v. Canada (Attorney General), 2020 FC 837 decision found that CIPO’s problem and solution framed “purposive construction” was inconsistent with the principles set forth by the Supreme Court of Canada (for more background information, please see our previous article). The CIPO has now issued examination guidance in light of this decision. The updated guidance will be applied effective immediately to applications currently in prosecution as well as those presently before the Patent Appeal Board.

We believe that the impact of this change in CIPO’s practice with respect to claim construction will positively impact the prosecution of many diagnostic method patent applications. In particular, a number of claims which were found to be directed to non-statutory subject matter when incorrectly construed using the problem solution approach may now be found to be directed to statutory subject matter when construed correctly using purposive construction.

To illustrate this impact, the following claim (from the examples included in CIPO’s notice) has been construed using CIPO’s incorrect problem solution approach and the correct purposive construction approach.


1. A method of diagnosing whether a human subject is at risk for developing cancer, comprising:

a. measuring the level of X in a biological sample from the subject; and

b. 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.

Under CIPO’s Incorrect Problem-Solution Claim Construction:

The typical problem CIPO would have identified for this type of claim under the problem-solution approach is a data analysis problem (i.e. relating the level of X to cancer risk). The solution to the problem CIPO would likely have identified would have been a correlation between cancer risk and the level of X and accordingly the steps related to measuring the level of X and comparing the level would have been regarded as non-essential. As such, the only element CIPO would have identified as essential would be the correlation between cancer risk. Such a correlation step is a disembodied idea and therefore the CIPO would have found that the claim is directed to non-statutory subject matter.

Under Purposive Construction:

There is no language in the claim indicating that any of the steps are optional. Accordingly, all the steps (including the steps related to measuring X and comparing the level of X) are essential.

As the essential elements are not limited to a disembodied idea, CIPO would find that the claim is directed to statutory subject matter.

Given this change in CIPO’s practice, we recommend reassessing any cases directed to diagnostic methods that were impacted by CIPO’s incorrect problem-solution claim construction methodology.

Please feel free to reach out to MBM if you need help regarding reassessing any cases directed to diagnostic methods.


For more information please contact:

Kay Palmer, Ph.D., Senior Patent Agent
T: 613.801.0452
E: kpalmer@mbm.com

Claire Palmer, Ph.D., Senior Patent Agent
T: 613.801.0450
E: cpalmer@mbm.com

This article is general information only and is not to be taken as legal or professional advice. This article does not create a solicitor-client relationship between you and MBM Intellectual Property Law LLP. If you would like more information about intellectual property, please feel free to reach out to MBM for a free consultation.


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