Is the Best Mode Requirement Restricted to Machines?

Western Oilfield Equipment Rentals Ltd v M-I LLC 2021 FCA 24 Locke JA: Gleason, Mactavish JJA affg 2019 FC 1606 O'Reilly J

            2,664,173 / Shaker and Degasser Combination

Previous posts have provided some background on this case and addressed reasonable compensation and the Gillette defence. Locke JA also made two noteworthy points with respect to the best-mode requirement set out in s 27(3)(c), which requires that the specification must “in the case of a machine,” explain the best mode of practising the invention. As discussed here, O’Reilly J had dismissed this argument on the basis that it “relates solely to machines and, as I understand the patent, it claims a method and a system, not a machine” [FC 146], [118]. Locke JA remarked that the mere fact that the claim at issue was phrased as being to “a system” did not in itself establish that it is not to a machine [119]. This makes sense to me; the question of whether the claim is to a machine should be a matter of the substance of the claim and not its form.

More importantly, Locke JA stated that “there is considerable doubt as to whether, despite the wording of paragraph 27(3)(c), the best-mode requirement is limited to machines,” citing various commentators [119]. This is interesting given that the FCA in Pfizer v. Novopharm / sildenafil (NOC) 2010 FCA 242 [72] approved Snider J’s holding in Ramipril FC 2009 FC 676 [329] that “the ‘best mode’ obligation only arises in the case of a patent to a machine.” I must say that Snider J’s textual analysis strikes me as fairly compelling, but far be it for me to dissuade the FCA from relying on commentators. Locke JA’s observation was expressly obiter, and the point made no difference to the outcome, but nonetheless the point can no longer be considered settled.