Under the doctrine of overbreadth (also referred to as "claims broader than the invention" and "covetous claiming"), a patent is invalid if its claims extend beyond the invention. While seemingly a straightforward idea, there is a lack of clarity for how such an allegation of invalidity is approached by the Court. Two recent Federal Court decisions, Les Laboratories Servier v Apotex (2019 FC 616) ("Laboratories Servier") and Aux Sable Liquid Products LP v JL Energy Transportation (2019 FC 581) ("Aux Sable"), have further muddied the waters in this area.

Allegations of overbreadth have generally been given a limited focus by the Court. Following the rejection of the promise doctrine by the SCC in AstraZeneca v Apotex (2017 SCC 36) ("AstraZeneca"), promise-type arguments were attempted and rejected under the ground of insufficiency. Similar arguments are now being made under the doctrine of overbreadth and, in Laboratories Servier and Aux Sable, have gained traction with the Court.

A promise by any other name

Generally speaking, the promise doctrine required a patentee to establish an elevated level of utility over what was mandated by the Patent Act. The promise doctrine had multiple faults, including that it could require a patentee to have demonstrated or soundly predicted multiple utilities, that it required the patentee to have demonstrated or soundly predicted that each embodiment found across the scope of the claim had utility for each of these promised uses, and that it could require patentees to prove that statements of advantage made in a patent's disclosure were demonstrated or soundly predicted by the filing date. Under the promise doctrine, the failure to meet any of these elevated requirements could result in the entire patent be invalidated. The promise doctrine was a uniquely Canadian patent law doctrine.

The promise doctrine was rejected by the SCC in AstraZeneca. The SCC noted that patent law is wholly statutory, and that to meet the Patent Act's utility requirement only a scintilla of utility for a single use related to the nature of the subject-matter of the claimed invention was required. However, despite this "killing blow" the promise doctrine remains an issue, with patent challengers continuing to try and re-frame promise arguments under other categories of invalidity. For example, a number of decisions in 2018 saw promise arguments advanced as grounds of insufficiency (under section 27(3)), relying upon the SCC's general comment in AstraZeneca that overpromising is a "mischief".

Until now, Courts have rejected attempts to re-incorporate the promise doctrine into validity attacks other than utility. For instance, in Hospira v The Kennedy Trust et al (2018 FC 259), Justice Phelan stated that "it would be inconsistent to discard [promise] doctrine only to have it resurface under another principle without clear language [in the Supreme Court's decision] to do so." Similarly, the Ontario Superior Court, in Apotex v Abbott Laboratories (2018 ONSC 5199) held that a party cannot simply raise promise based pleadings under a different ground of invalidity, and that the Court should "whack the zombies dead once and for all." Despite this initial pushback, Laboratories Servier and Aux Sable have seemingly revived the doctrine in the form of overbreadth allegations, as discussed below.

Les Laboratories Servier v Apotex

In Laboratories Servier, a decision under the pre-amended Patented Medicines (Notice of Compliance) Regulations that proceeded by way of application on a paper record, the Court applied a promise-type analysis to invalidate a claim that encompassed indisputably useful subject matter.

As background, the invention disclosed by the patent at issue was the arginine salt of the active molecule perindopril. The evidence was that a number of pre-filing date studies had been conducted using L-arginine demonstrating utility in the form of enhanced stability.

A dispute between the parties was the construction of the term "arginine" in the claims at issue. Laboratories Servier argued that "arginine" in the claims meant the specific isomer L-arginine, which is the naturally occurring form. Apotex argued that "arginine" meant all forms of arginine: L-arginine, D-arginine, or a mixture of both. The patent's disclosure specified that L-arginine was preferred, but that the claims did not include any such explicit limitation [174-179]. The Court ultimately held that a proper construction of "arginine" was the broader definition advanced by Apotex.

Apotex also alleged that the claims were overbroad as they were not explicitly limited to L-arginine salts. The Court agreed with Apotex, finding that the claims were overbroad as the inventors had not made or soundly predicted the usefulness of each and every arginine salt combination [219, 240-241].

Unfortunately, the Court's analysis was in essence a revival of the promise doctrine. It incorporated utility concepts, such as applying the sound prediction test to the different forms of arginine and limiting the patentee to the filing date as the relevant date. However, while the Court had previously found that the utility of the claimed invention was "unassailable" [188], this elevated utility analysis (i.e. promise analysis) was used in holding that the claims were overly broad.

In effect, the Court required the inventor to have not only conceived of the use of each form of arginine salt, as it appears was done, but to have gone further and established the utility of each and every type of arginine salt. This was an "across the scope" promise doctrine argument masquerading as overbreadth. Indeed, this was the very extra-statutory requirement underlying the promise doctrine which the SCC held to be incompatible with the Patent Act in AstraZeneca.

Aux Sable Liquid Products LP v JL Energy Transportation Inc

At issue in Aux Sable was the validity of a patent relating to the transportation of natural gas by pipeline. The Court found that claims 9 and 10 were broader than the invention. While claims 1-8 required the presence of certain hydrocarbon mixtures at select temperatures, claims 9 and 10 were compositions of gas mixtures with select parameters.

The main contentious issue was whether the compositions in claims 9 and 10 required the addition of specific hydrocarbons and transport at select temperatures, or if the same compositions could be achieved without those elements. A major limitation appears to be that there was no (or very limited) evidence from the inventor on this point.

A concerning aspect of the Court's analysis was the apparent requirement for "efficiencies" to be obtained by the composition of claims 9 and 10. The Court expressed concerns that the compositions in claims 9 and 10 would include "very inefficient selections" [68]. However, the basis for this conclusion stemmed from the utility evidence of Aux Sable's experts, which relied upon comments in the specification that were not present in the claims.

Drawing elements from the specification and importing them into the claims was a hallmark of the flawed promise analyses that were rejected in AstraZeneca. This problem was amplified by the fact that a near equivalent argument was advanced by Aux Sable in respect of utility, where the Court again held that claims 9 and 10 included within their scope "very inefficient mixtures", despite there being nothing within the wording of claims 9 and 10 to suggest a requirement of efficiency, and found the claims to lack utility. In short, the scintilla of utility requirement was seemingly bypassed in favour of a requirement that statements of advantages made in the specification be met - a requirement that was rejected in AstraZeneca.

Tackling overbreadth

In approaching overbreadth, the strongest approach for a patentee to take is to lead a detailed description of the whole project that led to the invention. This allows a description of not only what was claimed, but the additional elements that were conceived of by the inventor but ultimately not claimed. A strong evidentiary foundation setting out the work underlying the invention is useful when responding to a number of allegations of invalidity, and can only be beneficial where overbreadth has been raised.

Additionally, a patentee should be on guard for the reappearance of promise doctrine arguments such as demonstration across the scope of the claim, or requiring elevated utility or efficiency of the invention. Spotting these improper promise arguments early on can ensure that the legal assumptions applied by the challenger's experts are appropriately scrutinized and tackled head-on.