In Canada, a fee is to be paid upon request for examination of a patent application. Currently, there are no excess claim fees, so the same examination fee applies irrespective of the number of pending claims in the application. This is about to change with amendments to the Patent Rules that come into force October 3, 2022. To meet the patent term adjustment obligation under the Canada-United States-Mexico Agreement (CUSMA), the Patent Rules have been amended. One change is the introduction of excess claim fees. The rationale is to discourage applicants from filing an unnecessarily large number of claims and therefore reduce the time required for examination. The amendments will introduce a fee for each claim in excess of 20 to be added to the basic fee for examination of an application.

The introduction of excess claim fees is concerning, not merely because of the extra fees innovators will have to pay but because certain aspects of Canadian patent law and practice limit the options for pursuing related subject matter in related applications, making it necessary in some cases to include a large number of claims in an application in order to adequately capture desired and potentially desirable subject matter.

One aspect in particular is Canada's take on double patenting. Double patenting, which relates to the prohibition on obtaining multiple patents for a single invention, is prohibited in many jurisdictions, including Canada and the US. In both Canada and the US, two types of double patenting are recognized: “same invention” type refers to double patenting where the claims are essentially identical between the two patents; “obviousness” type refers to where the claims of a second patent are not “patentably distinct” from those of a first patent. Further, while “same invention” type double patenting may be easy to identify and therefore easy to avoid, “obviousness” type double patenting is less straight forward to determine. Added to this complexity is the Canadian patent office practice of requiring claims that are directed to the same “inventive concept” to be pursued in one patent even if they are different categories of claim – this requires product claims and method claims that are construed to be to the same inventive concept to be pursued in the same application. As a result, the application of double patenting in practice is very different in Canada and the US.

In the US, the procedural remedy for “obviousness” type double patenting (referred to as non-statutory double patenting) is for the patent owner to disclaim the terminal portion of the protection term of a subsequent patent relative to a first so that both patents expire at the same time. In Canada, such mechanism, called “terminal disclaimer” does not exist. If a patentee pursues a subsequent patent in Canada, the patent office will object to the patent application. If double patenting is alleged and successful in court, the later issued patent will be invalidated.

The strategy to avoid a double patenting attack in Canada is to include all claims of interest in a single application. The goal is to have the examiner raise a lack of unity of invention objection. With such an objection, the applicant can elect to proceed with one of the identified inventions and later file a divisional application for the non-elected subject matter. The divisional application will be immune to a double-patenting attack both by the patent office and the court. This strategy is a recognized local practice given the strict law on double patenting. The Patent Office in its Manual of Patent Office Practice states that it is up to the applicant “to ensure all the claims to a given invention are included in a single application.”1 Further, during the patent process, the final product to be commercialized may not be known. As the patent office will not allow an applicant to pursue claims that the patent office determines to be related to the same “inventive concept” and unified with claims of a parent, a plethora of claims are included at the onset as they cannot otherwise be obtained. Because of these practices, it is common for Canadian applications to have a large number of claims. This is feasible because there are currently no excess claim fees. An applicant can file hundreds of claims without incurring any additional cost.

Some may suggest that Canadian excess claim fees are better than those applicable to European patents as the European patent office charges significant fees for claims in excess of 15. European practice, however, allows the applicant to cascade embodiments, using terms such as “preferably”. This strategy is generally not available in Canada. Claim terms such as “preferably” are objected to as indefinite.2Therefore, local practice has been to separate embodiments into different claims. With introduction of excess claim fees, patentees under budget constraints may only be able to afford to protect certain embodiments of their invention.

Introduction of excess claim fees means the strategy to file all claims in a single application to trigger a lack of unity of invention objection to avoid a double patenting attack as presently practiced would become too costly for many patentees. To circumvent excess claim fees, applicants who wish to trigger a unity objection to avoid a double patenting attack may engage in tactics where claims are deleted in a voluntary amendment before requesting examination, then added back after requesting examination so all claims of interest are examined. This would create administrative burden and defeat the very purpose of amending the Patent Rules. Such tactics also incur additional costs for applicants.

As Canada amends its patent law to meet its international obligations, perhaps it is time for the Patent Office to reconsider some of its practices, for example, to allow claims with alternative embodiments in divisional applications. The law on double patenting should also be changed, for example, to introduce a mechanism similar to terminal disclaimer in the US. If the law is not amended in light of the disruption caused by the implementation of excess claim fees to long-standing practices and strategies in obtaining patent protection, disincentives will be created for some applicants to file in Canada and some companies to enter the Canadian market. Further, the desire to limit claim fees for large claims sets is likely to result in tactics such as those described above. These unintended consequences are likely to thwart attempts to streamline prosecution, and may result in administrative burden and cost to both the patent office and patentee while disincentivizing Canadian filings.


1. 18.06.03 of MOPOP.

2. See 16.03.02 of MOPOP.

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