Successful Before the TMOB, but Seeking More Evidence on Appeal: Federal Court Clarifies “Materiality” Under Section 56(5)

Recently, the Federal Court in Canadian National Railway Company v. Cambium Networks, Ltd., 2026 FC 1192, provided further guidance on when parties may be granted leave to file additional evidence on an appeal from the Trademarks Opposition Board (“TMOB”), including where the party seeking to introduce the evidence was successful before the TMOB.

 The underlying proceeding involved a section 45 summary expungement proceeding brought by Canadian National Railway Company (“CNR”) against Cambium Networks, Ltd. (“Cambium”) and its CNMAESTRO trademark. The TMOB maintained Cambium’s registration, finding that its evidence, although “flawed,” was sufficient to establish use of the trademark during the relevant period.

 CNR appealed, arguing that the TMOB erred in accepting Cambium’s evidence despite its shortcomings. On this motion, Cambium sought leave under subsection 56(5) of the Trademarks Act to file additional evidence addressing several of the evidentiary deficiencies identified by the TMOB and relied on by CNR on appeal.

 The Court applied the framework recently set out in Products Unlimited, Inc. v. Five Seasons Comfort Limited, 2026 FC 48. Under that framework, the Court considers whether granting leave is in the interests of justice, having regard to factors including (a) the relevance, credibility, and admissibility of the evidence; (b) the materiality of the evidence; (c) the circumstances surrounding the delay in filing the evidence; and (d) whether granting leave would cause prejudice to the opposing party.

 The parties’ arguments focused primarily on materiality. CNR argued that because Cambium had been entirely successful before the TMOB, its additional evidence could not have materially affected the TMOB’s decision. In CNR’s view, Cambium could not have been “more successful” before the TMOB had the additional evidence been filed.

 The Court disagreed. It held that materiality should be assessed having regard to the evidence before the TMOB, the TMOB’s findings and the issues raised on appeal. In particular, evidence that addresses shortcomings identified by the TMOB may be material even though those shortcomings were not ultimately fatal to the successful party. The Court observed that concluding otherwise could leave a party worse off for having succeeded before the TMOB, since it could be prevented from introducing evidence addressing deficiencies that the opposing party subsequently relies upon on appeal.

 The Court further explained that additional evidence may be material if it could affect the outcome of the appeal, even if it would not have changed the TMOB’s ultimate disposition. However, simply supplementing or repeating existing evidence will not reach this threshold. The proposed evidence must add something of probative value to the record that goes beyond what was in substance already before the board.

 In this case, the Court found that Cambium’s additional affidavit provided greater specificity regarding Cambium’s use of the CNMAESTRO trademark, including the entity using the mark and the goods and services with which it was used. The evidence therefore addressed shortcomings identified by the TMOB that were directly at issue on appeal.

 The Court also considered the timing of the proceeding. Cambium had filed its original evidence when the Trademarks Act still permitted parties to adduce additional evidence on appeal without first obtaining leave. While the Court emphasized that this did not provide Cambium with a “free pass”, this transitional timing is a relevant consideration and may even render a failure to explain the delay in producing evidence non-determinative. The Court also found that CNR had not established prejudice weighing against admission of the evidence.

 For these reasons, the Court granted Cambium leave to file the additional affidavit.

 This decision provides further guidance on the Court’s approach to the new leave requirement under subsection 56(5) of the Trademarks Act. In particular, it confirms that a party’s success before the TMOB does not necessarily prevent it from introducing additional evidence on appeal. Evidence addressing deficiencies identified by the TMOB may still be material where those deficiencies form part of the challenge on appeal, provided the evidence adds something of probative value rather than simply repeating the existing record.