The Canadian patent system provides multiple post-grant administrative procedures that allow patentees and third parties to challenge or amend Canadian patents without requiring legal proceedings before the courts. While these mechanisms are narrower than those available in the United States, they can be of strategic value in particular circumstances.
Re-examination
Section 48.1 of the Patent Act provides that any person, including the patentee, may request re-examination of one or more claims of a granted patent at any time during its term. The request must be based on prior art patents, published applications, or printed publications, and must explain how the cited art applies to the challenged claims. Accordingly, parties can only use re-examination to challenge the validity of a patent based on anticipation or obviousness.
For third-party patent challengers, re-examination can provide a more summary and less costly option compared to an impeachment action in the Federal Court; however, the circumstances where re-examination is likely to yield a desirable outcome for the third-party are relatively limited (as discussed in further detail below).
Stage 1 - Threshold review
Once a request is filed, the Re-examination Board (the “Board”) considers whether the request raises a “substantial new question of patentability” relating to the validity of one or more claims.
If the threshold is not met, the requester is notified with reasons. The Board’s determination of this threshold question is final and is not subject to appeal or judicial review. Third-party involvement (if any) ends once the request is filed; only the patentee may participate thereafter.
If the threshold criterion is met, the patentee is notified and has three months to provide responding submissions and/or propose amendments to the patent (provided such amendments do not broaden the scope of any claim). The Board then re-examines the claims, which may involve multiple rounds of correspondence between the Board and the patentee, similar to pre-grant examination. The re-examination process must be completed within twelve months.
Stage 3 - Completion and appeal
The Board ultimately issues a certificate cancelling, confirming, or amending claims. The patentee may appeal to the Federal Court within three months of receiving the certificate.
Re-examination is not akin to IPR or PGR proceedings in the United States
The Canadian re-examination procedure is most closely aligned with U.S. ex parte re-examination 35 U.S.C. § 303(a).
Canada does not have an equivalent to U.S. inter partes review (IPR) or post-grant review (PGR) proceedings. Consequently, there is no post-grant administrative procedure in Canada that permits ongoing participation by a third party, the introduction of expert evidence, or discovery steps.
Accordingly, subject to the limited use of re-examination in Canada, patent invalidity proceedings are typically brought by way of an impeachment action in the Federal Court.
Re-examination vs. impeachment
Impeachment is a full adversarial action before the Federal Court, involving pleadings, discovery, expert evidence, and trial, and typically takes up to two to three years to complete (plus the time required for any appeals).
Although re-examination offers a more streamlined process, it tends to favour the patentee and has significant downsides for third parties. Once a request for re-examination is filed, the third party’s right to participate in the re-examination ends. Further, the patentee is afforded the opportunity to overcome the asserted prior art by amending the claims, which can potentially strengthen the patent’s validity. Accordingly, if the third party is unsuccessful in invalidating the patent through re-examination, a subsequent impeachment action may be less likely to succeed than if re-examination had not been attempted first.
Re-examination is also confined to prior art challenges and does not allow third parties to raise other invalidity grounds available in Canada, such as insufficiency, ambiguity, or lack of utility. In contrast, an impeachment action allows the plaintiff to advance all relevant invalidity allegations simultaneously and force the patentee to defend against a broader and more complex set of invalidity issues without any opportunity to overcome them through amendment.
In view of the above, re-examination is typically used by third parties only in the clearest of cases where a very strong prior art reference raises a substantial new question of patentability which is not likely to be resolved by amending the claims. Otherwise, an impeachment action tends to be the preferred approach to advance a patent invalidity case in Canada.
Re-examination is also used in rare instances where a patentee becomes aware of highly relevant prior art after issuance of its own patent, and the prior art raises an issue which can be easily overcome with claim amendments.
Re-issue
Section 47 of the Patent Act allows a patentee to request a re-issue of a “defective or inoperative” patent within four years of grant, where the error arose from accident or inadvertence. The patentee must show that the patent is defective because of insufficient disclosure or because it claimed more or less than it was entitled, and may, in some cases, even broaden claim scope if the broader subject matter is supported by the original specification. Third parties may not initiate or participate in re-issue proceedings.
Re-issue is rarely used in Canada, owing to the strict four-year limitation period and the high threshold for demonstrating inadvertent error. In practice, it is most often employed to correct prosecution errors.
Disclaimer
Section 48 of the Patent Act allows a patentee to disclaim part of a granted patent. A disclaimer allows a patentee to narrow a patent claim (in whole or in part) by removing subject matter that was included by mistake, accident, or inadvertence, provided there was no intent to mislead the public. There is no time limit for filing.
If a disclaimer is properly filed, the Canadian Patent Office records the disclaimer without examining its substance. The patentee bears responsibility for ensuring it complies with statutory requirements.
Interplay between post-grant administrative procedures and patent infringement/invalidity actions
While post-grant procedures may appear to provide patentees with an opportunity to strengthen their patent claims while invalidity and/or infringement issues are pending or expected to be brought before the Court, such attempts tend to be ineffective in Canada.
The Court does not typically consider concurrent re-examination to justify the issuance of a stay of an ongoing impeachment action pending the outcome of the re-examination.1 In contrast, it is not uncommon for re-examination proceedings to be stayed pending the outcome of a concurrent impeachment action.2 Accordingly, impeachment actions typically proceed based on the impugned claims as they existed at the time the action was initiated.
Re-issue proceedings are not intended to provide the patentee with a second chance to redefine the invention to avoid invalidity issues or to try to capture an infringing product with hindsight. Accordingly, attempts to tailor claims post-grant in this way are open to being challenged before the Court.
Similarly, a disclaimer will not typically affect a patent infringement/impeachment action that is already underway.
Conclusion
Post-grant administrative procedures in Canada offer limited but targeted mechanisms to revisit the scope or validity of a patent outside of litigation. While these procedures can be useful for risk management or portfolio maintenance, their strategic value in active disputes is generally constrained.
Impeachment actions remain the principal and typically most effective mechanism for third parties to contest patent validity in Canada. For patentees, administrative options may offer complementary tools, but not substitutes, for addressing issues raised in court.
The preceding is intended as a timely update on Canadian intellectual property and technology law. The content is informational only and does not constitute legal or professional advice. To obtain such advice, please communicate with our offices directly.
References
- See, e.g., Pfizer Canada ULC v Uniqure Biopharma BV, 2023 FC 629.
- See, e.g., Teva Canada Innovation v Pharmascience Inc 2021 FC 367; Camso Inc v Soucy International Inc, 2016 FC 1116; and Prenbec Equipment Inc v Timberblade Inc, 2010 FC 23.