Same Defence, Better Facts: Federal Court Allows Amendments to Bolster Prior Use Allegation

In Kobold Corporation v NCS Multistage Inc., 2026 CanLII 38519 (FC), the Federal Court granted NCS leave to amend its statement of defence to plead additional facts supporting a prior use defence under section 56(1) of the Patent Act, even though NCS had already sought—and lost—a summary judgment motion on its prior use defence. The decision provides useful guidance on issues that survive summary judgment and the scope of the ‘best foot forward’ principle in patent litigation.

Procedural Background

Earlier in the litigation, NCS sought summary judgment based on a prior use defence, arguing that its allegedly infringing tools functioned in the same or substantially the same manner as earlier tools used before the patent’s claim date.^[1] The Court dismissed the motion, holding that infringement and the prior use defence required a trial.^[2]

Following the motion, NCS sought leave to amend its pleadings to allege that one of the allegedly infringing tools had been commercially used before the claim date—a new allegation in support of its prior use defence.^[3]

Kobold opposed, arguing that NCS was required to put its best foot forward on its summary judgment motion and could not present an improved prior use defence at trial.^[4] Kobold further argued that the amendments constituted a radical departure from NCS’s earlier position and would cause prejudice.^[5]

Best Foot Forward Does Not Bar Later Steps

The Court rejected Kobold’s arguments, clarifying that the ‘best foot forward’ principle merely requires the court to assume the parties have put forward their full evidence for the purpose of assessing summary judgment. It does not prevent a party from advancing new evidence at trial if the court decides that summary judgment should not be granted.^[6]

The Court distinguished summary judgment from summary trials, holding that an issue that is dismissed at summary trial cannot be relitigated. On the other hand, where a summary judgment motion is dismissed because the issue requires a trial, nothing prevents the issue from being more fulsomely advanced so long as the ordinary rules of pleadings and procedure are respected.^[7]

^[1] Kobold Corporation v. NCS Multistage Inc., 2026 CanLII 38519 (FC) [NCS] at para. 3.

^[2] NCS, at paras. 5-6, see also Kobold v. NCS Multistage Inc., 2021 FC 1437.

^[3] NCS, at paras. 14-15.

^[4] NCS, at para. 22.

^[5] NCS, at para. 25.

^[6] NCS, at paras. 23-24, citing Rude Native Inc. v. Tyrone T. Resto Lounge, 2010 FC 1278 at para. 16.

^[7] NCS, at paras. 22-23.