Don’t settle for less: Maximizing patent protection in Canada

Canada think big keyboardMost patent professionals, applicants and inventors who have prosecuted the same patent application in Canada and the US will have heard that if you have a US patent, filing an amendment including the corresponding claims in Canada is very likely to lead to quick allowance. This however may not be in the applicant’s best interests. A careful review of the whole US prosecution history and a conversation about patent strategies with the applicant are in order before making such a seemingly benign decision. The same probably applies to many other countries with which I am less familiar.

In Canada, examination is not automatic after filing, as it is in the US, but must be requested within 5 years of filing. When a corresponding US patent application is filed, if the invention is patentable, the US patent will almost always issue before the deadline for requesting examination in Canada in most technological fields. Applicants wishing to reduce prosecution costs may be tempted to simply file the claims that were allowed in the US when requesting examination, which almost always leads to a notice of allowance if the Canadian practitioner also adapts the specification to Canadian practice. However, there are many differences between the Canadian and US practice and an applicant following this strategy may be forfeiting a lot of patent breadth.

In most cases, when examination of a corresponding US patent has started and claims similar to claims rejected in the first office action in the US are pending in Canada, the Canadian examiner will issue an office action that mirrors the US one. The first thing to do in this case is to make sure that the documents cited in the US are also citable in Canada. The second thing to do is to carefully consider any obviousness rejection. Indeed, the standards for obviousness are stricter in Canada than in the US.  Valid obviousness rejections made in the US can sometimes be overcome in Canada, and are also sometimes not even made by the Canadian examiner. Since final office actions are rarely issued in Canada, using this strategy can be very advantageous as it often happens that the Canadian examiner will stop mirroring US prosecution at some point where the Canadian claims are broader than the corresponding US ones. This is especially true if the US examiner was particularly difficult and the applicant settled for claims narrower than what he thought he was entitled to because of exploding prosecution costs.


When I receive an office action in Canada that includes obviousness rejections, my first reflex is to look at arguments that were presented in the corresponding US case, if applicable. If these arguments were enough to overcome the US rejection without amendments, it is likely that they will be accepted also in Canada. Even if the next US office action issued with other obviousness rejections, it often happens that the Canadian examiner will not issue another office action as the US examiner often must combine additional documents to make the subsequent rejection, which makes the invention less obvious. In some cases, these arguments may also be unconvincing to the US examiner, but found sufficient to overcome the Canadian rejections. I obtained many Canadian patents for my clients in this manner at relatively small additional costs as the main arguments made in the US only needed to be reformulated in accordance with Canadian practice.

In some cases, amendments were presented in the US which are thought to be necessary to overcome the rejection in Canada. As with a response filed without amendments as described in the previous paragraph, even if the US examiner kept on formulating obviousness rejections in subsequent office actions, the Canadian examiner will not necessarily go down the line of US office actions to issue all the same rejections in sequence. Also, if the Applicant agrees to spend more money on the Canadian response, additional arguments can be presented as the rejection can be further analyzed in view of Canadian practice, which increases the likelihood of obtaining a broader patent in Canada.

Another unnecessary limit that US applicants almost always impose on themselves is in the number of claims. In Canada, there are no extra claim fees. As we all know, more claims are most of the times a good thing. In many cases, adding claims would require additional drafting and the applicant may not be willing to spend more on claim drafting. However, there are a few cases in which additional drafting efforts are small and for which adding existing claims to the Canadian patent application would be cost effective.

The first one is when the above-described prosecution strategy is used. It may be the case that the US patent corresponding to a Canadian patent application includes some claims that are narrower than any of the claims pending in Canada. Even if the Canadian examiner is ready to allow broader claims, adding claims commensurate in scope to these narrower US claims can increase the patent’s robustness in litigation for a very small cost.

Another case is when the US patent is part of a larger family including continuations or divisionals. Claims that were fully supported by the application as filed should be introduced in Canada as early as possible in prosecution. In some cases, the Canadian examiner will issue a unity of invention rejection, equivalent to a restriction requirement, but this is a small price to pay. Indeed, there is a double patenting doctrine in Canada, but no terminal disclaimer practice. The only way to ensure that there is no double patenting issue is to have the examiner issue the unity of invention rejection. For this reason, voluntary divisional applications are not recommended in Canada.

Another strategy that can be used is to claim the invention with claim families having slightly different independent claims. While more expensive than the other strategies mentioned above, having many independent claims of slightly different scope and having each of these independent claims include a whole family of dependent claims obviously offers better protection than a single independent claim, or a few independent claims with only one of them fully developed with dependent claims. At the very least, if the US patent includes only one fully developed set of claims with a few additional ones with a reduced set, for example the invention, the invention in a system, etc…, adding all the dependent claims that apply to each independent claim is relatively inexpensive to do, but may not have been done in the US to avoid an excessively large filing fee.

US practitioners seldom, if ever, use multiple dependent claims as they are heavily penalized by excess claim fees. However, this is not the case in Canada. Ideally, a set of claims including multiple dependencies should be filed at the time of filing in Canada, or even at the PCT stage. I never had any problem introducing multiple dependencies after filing, but there could be new matter objections made if no multiple dependencies were present in the original filing, either at the patent prosecution stage, or during litigation. As a side note, anyone filing a PCT application should strongly consider filing multiple dependent claims, as some jurisdictions, such as Europe, will object to their addition later unless explicitly supported by the specification. Adding multiple claim dependencies is a quick and effective way of greatly increasing the number of claims, especially if the claim structure includes a few main branches, such as Claim 1: invention A, Claims 2-4: with feature B, and a few dependents, Claims 5-8: with feature C, and a few dependents, etc…

The breadth and robustness of a Canadian patent can be increased at relatively low costs, even for the most cost-conscious applicants. At the very least, multiple dependent claims should be filed and the restriction on the number of claims due to extra claim fees should be put aside to add to the application the claims that are already present in corresponding US applications and patents. For the Applicant who wishes to optimize his Canadian patent, fighting rejections mirroring US prosecution and not simply filing in Canada issued US claims that were amended during US prosecution is worthwhile and can often lead to broader Canadian patents.


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One comment so far.

  • [Avatar for Manu Mitra]
    Manu Mitra
    February 16, 2017 02:41 pm

    What is the rejection ratio between US patents and Canadian Patents ?