Federal Court relies on foreign prosecution history in first application of file wrapper estoppel

In CanMar Foods Ltd. v TA Foods Ltd., 2019 FC 1233, the Federal Court interpreted and applied the new file wrapper estoppel provision, section 53.1 of the Patent Act, RSC 1985, c P-4, for the first time. While CanMar is not a life sciences case, the application of Canada’s new file wrapper estoppel provision has implications for patentees generally.

In CanMar, the patentee contended that two elements of the claim at issue were non-essential. The Court reached the opposite conclusion by relying on prosecution history evidence admitted under section 53.1, and set out a test for the circumstances under which the Court will admit evidence from a foreign file wrapper under this provision. For a more detailed analysis of the Court’s analysis and findings, be sure to read our IP Monitor publication.