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Canada Proposes Introducing Patent File Wrapper Estoppel

Bill C-86, the Budget Implementation Act is an 884 page omnibus bill recently introduced in Parliament. Among a myriad of other items, the bill contains proposed amendments to the Patent Act, which include the introduction of file wrapper estoppel in Canada.

Positions taken, or statements made, by patent applicants during the patent application process can be introduced as evidence in patent litigation in U.S. courts. This is known as “file wrapper estoppel” (since a party is effectively estopped from taking a position that is inconsistent with what’s in the patent’s “file wrapper”). File wrapper estoppel has not existed in Canada since at least the Supreme Court’s 2000 decision in Free World Trust, although at least one Federal Court Judge has questioned, in light of internet-accessible file histories that were not available when Free World Trust was decided, whether it is time to revisit the prohibition of using extrinsic evidence for the purpose of claims construction.

Bill C-86 proposes the following amendment to the Patent Act that would allow for file wrapper estoppel in Canada:

Admissible in evidence

53.1 (1) In any action or proceeding respecting a patent, a written communication, or any part of such a communication, may be admitted into evidence to rebut any representation made by the patentee in the action or proceeding as to the construction of a claim in the patent if

(a) it is prepared in respect of

(i) the prosecution of the application for the patent,

(ii) a disclaimer made in respect of the patent, or

(iii) a request for re-examination, or a re-examination proceeding, in respect of the patent; and

(b) it is between

(i) the applicant for the patent or the patentee; and

(ii) the Commissioner, an officer or employee of the Patent Office or a member of a re-examination board.

Divisional application

(2) For the purposes of this section, the prosecution of a divisional application is deemed to include the prosecution of the original application before that divisional application is filed.

Reissued patent

(3) For the purposes of this section, a written communication  is deemed to be prepared in respect of the prosecution of the application for a reissued patent if it is prepared in respect of

(a) the prosecution of the application for the patent that was surrendered and from which the reissued patent results; or

(b) the application for reissuance.

The amendment would be a major change to Canadian patent litigation, as it would prevent patent holders from taking positions during litigation that differs from positions they took before the patent office in order to obtain their patent.

The transitional provisions of Bill C-86 state that the new rule would apply to any “action or proceeding that has not been finally disposed of” when the section comes into force.

Bill C-86 received first reading on October 29, 2018 and still has some way to go before becoming law.

A copy of Bill C-86 can be found here.