Excess patent claim fees and Canadian double patenting – unintended consequences?

June 21, 2022

In Canada, a fee is to be paid upon request for examination of a patent application. Currently, there are no excess claims fees, so the same examination fee applies irrespective of the number of pending claims in the application. As noted in an earlier article, this is about to change with amendments to the Patent Rules that introduce excess claims fees coming 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 claims 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 that is present at any time from requesting examination to payment of the final fee.

The introduction of excess claims 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 divisional applications, making it often necessary to include a large number of claims in an application to adequately protect 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. Adding 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 – requiring for example product claims and method claims that are deemed to be related, 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. Furthermore, in Canada there is no procedural remedy for “obviousness” type double patenting (also referred to as non-statutory double patenting). In the US. the patent owner can file a “terminal disclaimer” which in effect disclaims any 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 does not exist.

As a result of these practices, the Canadian patent office may object to a voluntary divisional application if the subject matter is related to the same “inventive concept” as the parent. Alternatively, if double patenting is alleged and successful in court, the subject claims of the later filed patent will be invalid.

The strategy to avoid a double patenting attack in Canada is to consolidate all claims of interest in a single application. The goal is to have the examiner raise a lack of unity of invention objection on the record. With such an objection, the applicant can then 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 shielded 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 onus for identifying what is considered a single invention falls on the patentee. The Patent Office’s 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] Because of these practices, it is common for Canadian applications to have a large number of claims, particularly in chemical and life science technologies. This is feasible currently because there are currently no excess claims fees.

Introduction of excess claims fees means the strategy to file all claims in a single application as presently practiced would become prohibitive for many patentees. To circumvent excess claims fees, applicants may engage in tactics where a voluntary amendment is filed when requesting examination to include primarily independent claims. For example, dependent claims may be deleted by voluntary amendment when requesting examination, and then reintroduced after receiving a unity objection and deleting non-elected claims. Applicants may also try to include multiple embodiments in each claim which may add complexity and so may not meaningfully reduce examination time. These tactics may create unexpected administrative burden and defeat the stated purpose of introducing excess claim fees.

Patentees may also delete embodiments, potentially reducing the breadth of protection of any patent obtained. This may be particularly true for cost sensitive patentees and those in the life sciences where claim numbers tend to be higher. Further, the lack of claim fees has long been touted as an advantage of the Canadian patent system and a work around to Canada’s onerous divisional practice.

As Canada implements amendments to its patent law to meet its international obligations, perhaps it is time for the Canadian Patent Office and lawmakers to reconsider practice and law related to double patenting. The strength and value of patent protection obtained may otherwise be unintentionally affected. Further, the desire to limit claim fees for large claim sets is likely to result in tactics such as those described above. These unintended consequences may thwart attempts to streamline prosecution and may result in administrative burden and cost to both the patent office and patentee.


[1] 18.06.03 of MOPOP.

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