A Word Of Caution: File Wrapper Contents Can Come Back To Haunt You

The Federal Court made a sweeping statement in Justice Locke's decision released last Friday that submissions made to the Canadian Intellectual Property Office (CIPO) during patent prosecution can re-emerge to haunt litigants and hit them where it hurts: the wallet.

On January 27, 2017, the Federal Court released a new decision for the Pollard Banknote Limited v BABN Technologies Corp1 matter. Pollard Banknote Ltd., the successful plaintiff from last summer's patent impeachment trial, was awarded costs elevated by 50% above the usual rate for allowable counsel fees and disbursements under the Federal Courts Rules.2 Several issues concerning conduct of the defence throughout trial grounded the elevated costs award in the judgment,3 and Justice Locke specifically denounced the fact that the defendant reversed the previous stance taken on claims construction during prosecution of the patent at issue. Justice Locke noted that "based on jurisprudence that is clearly binding on me, I ignored the position that SG took during prosecution. Instead, I adopted the claim construction position that SG argued at trial. But I observed that it was "breathtaking" to see SG take this position on claim construction without addressing the fact that it reintroduced the problem of obviousness that it had overcome during prosecution by asserting the contrary claim construction position."4

Therefore, patent litigants be forewarned: this latest decision, in combination with the reasons penned by Justice Locke following last summer's patent impeachment trial, makes it clear that file wrapper contents are not laid to rest in Canada once a patent application goes to grant. This point was also highlighted in last summer's Federal Court judgment that, in one fell swoop, invalidated the patent at issue and breathed new life into the long-dead issue of patent file wrapper estoppel doctrine applicability in Canada.

The doctrine of patent prosecution history estoppel (commonly known as "file wrapper estoppel") is in full force in the U.S., where it enables courts engaging in claims construction to consider representations made by inventors to the Patent Office during the patent prosecution process. Because inventors before U.S. courts can become "tied" to previous assertions made to the Patent Office concerning the scope of the monopoly claimed, some argue that operation of the doctrine helps conserve valuable resources by abridging or avoiding drawn-out patent disputes and...