Once the Cat is Out of the Bag – A Canadian Update

July 29, 2020
By Isi Caulder, Maria Wei and Parnian Soltanipanah

Our earlier article Once the Cat is Out of the Bag provides an overview of patent grace periods in various jurisdictions, including Canada. Since then, amendments to Canada’s Patent Act to ratify the Patent Law Treaty came into force on October 30, 2019. This article provides an update on how these changes affect Canada’s grace periods.  

As a general recap, for an invention to be patentable, it must be novel and inventive. To assess whether the patent application meets these requirements, the patent office looks to the “prior art” available in the public domain at the time the application was filed. Prior art can include information or documentation about an invention that has been made public by the inventor themselves. Public disclosure of an invention prior to filing the application can thwart patent protection.

Fortunately, Canada provides a “grace period” for inventors that have made public disclosure prior to filing a patent application. Public disclosures made during the grace period by the inventors do not constitute prior art against the inventor’s own invention.

Out With the Old (Patent Act), and In With the New

Canada provides a 12 month grace period calculated from the Canadian filing date. However, grace periods and claiming priority are interrelated. Prior to the Patent Act changes to ratify the Patent Law Treaty, applicants had 12 months to file an application after public disclosure. At the same time, applicants have a 12 month deadline for claiming priority to an earlier filed application.

To comply with the Patent Law Treaty, the Patent Act was amended to provide a two month window for restoring priority after the expiration of the priority period, if the failure to file in time was unintentional. That is, instead of a 12 month deadline for claiming priority to an earlier filed application, applicants can claim priority within 14 months of an earlier filed application if the failure was unintentional.1

Without the additional changes to the grace period, if an applicant had publicly disclosed the nature of the invention within the first two months of filing the original application, the applicant would be subject to a strict 12 month time frame to file subsequent applications to ensure they were abiding by the grace period. Meaning, that if the applicant unintentionally forgot to file within 12 months, they would be unable to make use of the new two month extension on restoring priority.

To avoid such a scenario, the grace period provisions in respect of novelty and inventiveness (subsections 28.2(1)(a) and 28.3 of the Patent Act), were also amended to give full effect to this restoration of priority provision. Amended subsections 28.2(1)(a) and 28.3 extend the grace period up to potentially 14 months so that applicants can make full use of the modified restoring priority guidelines. Something to note, is that the extension to the grace period only occurs in tandem to claiming priority, if/when the 12 month deadline was missed unintentionally.

What Does This Amendment Mean for Applicants?

In essence, what the amendments mean for applicants is that, should they publicly disclose their invention within the first two months after filing their original application, and then unintentionally miss the 12 month deadline to claim priority to that original application, they get an additional two months to claim priority, without being held back by the grace period deadline. The grace period in that situation, can be extended by up to two months.

Under the new amendments to the Patent Act, applicants are still generally required to file a patent application within 12 months of public disclosure. However, the amended Patent Act, provides more leeway for applicants who restore priority after unintentionally missing the 12 month deadline for claiming priority, and who previously made public disclosures within the first two months after filing their original priority application. This is good news for applicants, as it provides a welcome safety net to an otherwise unforgiving deadline that applicants must meet.

1 Canadian Intellectual Property Office, Patent Law Treaty – Changes Required to Canadian Law & Practice, by Alan Troicuk, (updated June 2013), online:


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