The Federal Court has now released the first decision in which
the scope of Section 53.1 of the Canadian Patent
Act—the so-called "file wrapper estoppel"
provision—has been considered. We recently published an
IP Update describing new Section 53.1 and the state of the law
regarding file wrapper estoppel in Canada.
In Canmar Foods Ltd v TA Foods Ltd, 2019 FC 1233 [Canmar Foods],the Court
held that representations made by a patentee during prosecution of
a foreign patent application constituted admissible evidence under
Section 53.1. The Court recognized that Section 53.1 only specifies
using Canadian prosecution file histories to rebut positions taken
on claim construction, and makes no reference to prosecution
histories from other jurisdictions. Notwithstanding, the Court
found that it could consider the U.S. Application prosecution
history as part of a purposive construction of the claims in issue,
based on the "extraordinary circumstances" identified by
the Court
