Similar to other jurisdictions, a patent in Canada is granted for one invention only. Accordingly, in instances where multiple inventions are claimed in a single application, it may be necessary to parse out the inventions and protect them by filing divisional applications. However, care must be taken to avoid potential double patenting issues.

The Supreme Court of Canada held in Whirlpool that double patenting has two types. The first type is referred to as "same invention" double patenting. Same invention double patenting occurs when the claims of a pending application or issued patent are identical or conterminous with the claims of an earlier-issued patent. The second type is referred to as "obviousness" double patenting. Obviously, double patenting occurs when the claims of a pending application or issued patent, while different, are not patentably distinct from the claims of an earlier issued patent.1

Addressing allegations of the same invention double patenting is usually straightforward. Either the claims have the same scope of protection, or they do not. However, allegations of the obviousness of double patenting can be more difficult to address and overcome. There is no simple mechanism to overcome obviousness-type double patenting objections, such as the Terminal Disclaimer practice that is available in the United States.

Accordingly, it has been necessary to develop strategies to limit the likelihood of facing a validity attack on the basis of double patenting.

In Consolboard Inc., the Supreme Court found that the patentee "was required by the Commissioner of Patents to divide his application into two parts... in my view a patentee is not to be prejudiced by enforced divisional applications."2

Accordingly, immunity from invalidity attacks for double patenting could be found for divisional applications if they were "forced" or filed in response to a unity of invention objection raised by the Examiner during the prosecution of the parent application. That is, if the examiner objected to the claims in a patent application as being directed to two inventions, A and B, the claims directed to invention B could be deleted from the application and filed in a divisional application. In view of Consolboard Inc., such a divisional application should be immune from subsequent invalidity attacks for double patenting. Of course, it should be noted that the scope of the claims in the divisional application should be substantially the same as those to which the objection was raised in the parent application.

However, recent decisions suggest that unity of invention objection issued in a parent application may no longer be sufficient to overcome a subsequent allegation of double patenting.

In Abbott Laboratories, consistent with the decision in Consolboard, Inc., the Federal Court found that the "Applicants provided evidence to show that claims respecting the improved taste profile were divided out of the '266 Patent at the request of the Commissioner of Patents... In my opinion, it would be unfair and inequitable to find that the '395 Patent should be invalidated, only because the Applicants had followed the directions of the Commissioner."3

In contrast, in Biogen Canada Inc., the Federal Court found that the characterization of the divisional as a "forced" divisional was "an overstatement, as the August 26, 2011 Office Action was an objection, rather than a rejection by way of a 'final action.' At this point in the prosecution process, [the Applicant] Acorda's election to proceed with the use claims and file a divisional for the method claims was voluntary. If [the Applicant] Acorda felt that the unity of invention objection was not merited, it could have advocated that the responder method was indeed part of the claimed use invention."4

More recently, in NCS Multistage Inc., the Federal Court suggested that the preferred approach to the question of double patenting is an "informed middle ground. Where an inventor can trace the origin of the divisional back to a direction of the Commissioner, it will be immune from double patenting attacks. However, where a voluntary divisional has been made by the applicant, at their cores the divisionals must disclose different inventions to avoid double patenting attacks. An applicant should not be penalized for electing for a divisional, but such an election should not be a mere attempt to secure the claims and take advantage of the earlier priority date of the parent patent."5

The Federal Court devoted some discussion as to whether the claims in the divisional patent actually correlated to the subject matter restricted from the parent patent. During prosecution of the divisional patent, the scope of the claims appear to have been amended away from the scope of the claims objected to in the parent patent. However, this difference on its own does not appear to be the basis for the Federal Court's decision to consider the patent not to be a "forced" division.

Rather, the Federal Court noted that the language of the Patent Act with respect to divisional applications has changed from the time of Consolboard Inc. Specifically, the version of the Patent Act at the time of Consolboard Inc had a single section dedicated to divisional applications. The current version of the Patent Act has two sections dedicated to divisional applications. Subsections 36(2) and 36(2.1) of the current Patent Act relate to divisional applications and read as follows:

Limitation of Claims by applicant

(2) Where an application (the "original application") describes more than one invention, the applicant may limit the claims to one invention only, and any other invention disclosed may be made the subject of a divisional application, if the divisional application is filed before the issue of a patent on the original application.

Limitation of Claims on direction of Commissioner

(2.1) Where an application (the "original application") describes and claims more than one invention, the applicant shall, on the direction of the Commissioner, limit the claims to one invention only, and any other invention disclosed may be made the subject of a divisional application, if the divisional application is filed before the issue of a patent on the original application.

The Federal Court suggested that "subsection 36(2.1) is comparable to the Supreme Court's wording of 'enforced divisional application' in Consolboard at paras 536-537. This further supports adopting the approach in Biogen FC."6 Thus, this decision appears to suggest that only objections under subsection 36(2.1) of the Patent Act can insulate a divisional patent from a subsequent allegation of double patenting.

In view of Consolboard Inc., it has been common practice in Canada to file divisional applications in response to an Examiner's objection under subsection 36(2) of the Patent Act. That is, until recently both the courts and the Patent Office have considered such divisional applications (and the resulting patents) to be filed at the direction of the Patent Office ("forced"), and thus immune to the allegation of double patenting. However, the recent decisions in Biogen Canada Inc. and NCS Multistage Inc. suggest that this may no longer be true.

It may be premature to worry as Biogen Canada Inc. and NCS Multistage Inc. have not been affirmed by the Federal Court of Appeal, at least as the decisions relate to double patenting. Accordingly, it is possible that they may be overturned. Further, in neither case was the patent in question found to be invalid because of double-patenting.

Accordingly, when prosecuting an application in Canada, if there is any doubt that a double patenting objection raised under subsection 36(2) of the Patent Act is proper, you may wish to consider rebutting the objection. Further, you may wish to request that the Examiner reject the claims under subsection 36(2.1) of the Patent Act if they maintain the objection.

Footnotes

1. Whirlpool Corp. v Camco Inc, 2000 SCC 67, at paras. 65 and 66

2. Consolboard Inc. v. MacMillan Bloedel (Sask.) Ltd., [1981] 1 SCR 504, at page 536

3. Abbott Laboratories v. Canada (Health), 2009 FC 648, at para. 193

4. Biogen Canada Inc. v. Taro Pharmaceuticals Inc., 2020 FC 621 at para. 106

5. NCS Multistage Inc. v. Kobold Corporation, 2023 FC 1486 at para. 245

6. Ibid, at para. 1246

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.