New Streamlined System for Remedying Double Patenting is on the Horizon for Canada

By Wendy Lamson
April 17, 2019

If you ask a patent practitioner in the U.S. what the most frustrating aspect of Canadian prosecution is, chances are they will say it’s Canada’s double patenting laws.  However, new Rules projected to come into effect late 2019 will help streamline the complex procedures to navigate double patenting and hopefully avoid some of the headaches felt by the industry at present.  Nevertheless, as discussed below, there are some caveats to note.

Current procedure

Shortly before issuance of a Canadian patent application, it is common practice to review the claims about to be allowed and to add a new set to ensure that the client’s scope of protection is aligned with business strategy.  For example, a client may want to add new claims that cover a product close to market entry not covered by the allowed claims, but supported by the specification as filed.  In another scenario, a company may want to pursue broader claims to capture some known infringing activity.  In the United States, a continuation application can be filed quite easily at this stage to pursue such new claims.  The most similar procedural counterpart in Canada is to voluntarily file a divisional patent application.  However, in Canada, filing such a voluntary divisional patent application will invite a double patenting rejection in view of the parent.  On the other hand, however, after allowance, an application generally cannot be amended to consolidate claims in a single application as prosecution on the merits is generally closed at this stage.[1]  Usually, the only mechanism available to pursue new claims is to allow the application to go abandoned for failure to pay the final fee and then reinstate.  Reinstatement re-opens prosecution on the merits and only then can the new claims can be added to the application.  Should a unity of invention objection be raised, a divisional can be filed that cannot be invalidated by the parent after it has issued.[2]

New streamlined practice

The Patent Act is presently being amended to simplify the abandonment/reinstatement procedure to introduce new claims after prosecution is closed.  The new proposed procedure will allow a Notice of Allowance to be withdrawn within 4 months from its mailing date.  A fee can then be paid to re-open prosecution, at which time the new claims can be added to the application, and the claims will undergo examination.  Again, if a unity objection is raised, a divisional can be filed that is immune to a double patenting rejection.

The new Rules are only proposed at this time but are projected to come into effect late this year (2019).  The published Rules in their final form likely will be published in Canada Gazette, Part II in a few months, but no further significant changes are expected.

Some caveats

However, not all things are rosy.  Generally, the new Rules will speed up the process from filing to issuance due to more compact prosecution.  For example, the new proposed deadline for responding to an examiner’s report is 4 months instead of the present 6 months.  Moreover, a request for examination will need to be filed within 4 years from the Canadian filing date, while currently, the deadline is 5 years.  The overall effect is that there will be fewer opportunities for applicants to defer issuance to a later date when there might be more information available to provide informed decisions regarding claim strategy.  While this might not be a concern for products with a short life-cycle, it may have a greater impact on products subject to regulatory approval, such as pharmaceuticals.


The foregoing simply provides an overview of double patenting issues that may arise during prosecution in Canada. It should be noted that each double patenting issue has its own unique challenges, and so the foregoing does not constitute legal advice.  However, our team at Perley-Robertson, Hill and McDougall is available to help patent applicants navigate Canada’s complex double patenting laws.

[1] Except to add claims that do not necessitate a further search by the Examiner.
[2] Consolboard Inc. v. MacMillan Bloedel (Sask.) Ltd. [1981] 1 SCR 504.  Dickson J stated that “[i]f patents are granted on divisional applications directed by the Patent Office, none of them should be deemed invalid, or open to attack, by reason only of the grant of the original patent.” (Emphasis added).


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