The “Promise of the Patent” Argument


Will the Appeal of the Plavix Case to the Supreme Court of Canada Sound the Death Knell for this Invalidity Attack on Patents?

In order for an invention to receive patent protection, it must be novel, useful and non-obvious.1 To establish usefulness or utility, an invention must provide some sort of useful commercial or industrial function and in certain circumstances, a trace of utility may be sufficient.2 However, while a mere trace is necessary to establish utility, it is not sufficient on its own. This is because the doctrine of promise is embodied in the utility requirement. The doctrine of promise provides that in order to constitute a useful invention, an invention must not only be useful for some purpose but it also must deliver any utility that was promised in the patent specification. The promise of a patent may either be demonstrated or soundly predicted in order to establish utility. Whether this threshold has been met will be evaluated at the time of filing the application for the patent a prominent role in this decision as the utility was established by the Court by inferring a promise from the description, including the promise to reduce a number of drawbacks of the prior art.

While widely used in Patented Medicines (Notice of Compliance) proceedings and actions under the Patent Act regarding pharmaceuticals, the argument of the “promise of the patent” has nonetheless made its way into other spheres of technology.

Bauer Hockey Corp. v Easton Sports Canada Inc.3 and Eurocopter v Bell Helicopter Textron Canada Ltee.4 (“Eurocopter”) are two non-pharmaceutical cases where the argument was raised. In Eurocopter, many of the claims of the patent in issue were found invalid for lack of demonstrated utility or sound prediction. The doctrine of the “promise of the patent” played a prominent role in this decision as the utility was established by the Court by inferring a promise from the description, including the promise to reduce a number of drawbacks of the prior art.

Sound Prediction

There are three elements necessary to support a finding of sound prediction:

(i) a factual basis for the prediction;

(ii) an articulable and sound line of reasoning from which the desired result can be inferred from the factual basis; and

(iii) proper disclosure of the first two elements.5

The doctrine of sound prediction exists to support situations where an applicant may be unable to demonstrate that an invention is useful but may be able to make a scientifically (or technologically) credible educated guess. The Supreme Court of Canada (the “SCC”) has explained that the policy rationale as follows:

The doctrine of “sound prediction” balances the public interest in early disclosure of new and useful inventions, even before their utility has been verified by tests (which in the case of pharmaceutical products may take years) and the public interest in avoiding cluttering the public domain with useless patents, and granting monopoly rights in exchange for misinformation.6

Doctrine of the “Promise of the Patent”

The promise of the patent doctrine has proved confusing in Canadian jurisprudence. Recent decisions have resulted in patents, for what appear to be useful inventions, being declared invalid because the promised utility could not be established as of the applicant’s filing date. The promise doctrine is not explicitly found in the Patent Act or in the legislation of foreign jurisdictions (such as the US and the EU). In 2013, the SCC dismissed the opportunity to clarify the doctrine when it denied leave to appeal of the Eli Lilly7 case. In that case, the Federal Court held that the patent in question had a promise that a drug called olanzapine was “substantially better” in the treatment of schizophrenia than other known anti-psychotics. The individual advantages of olanzapine asserted in the comparison with other compounds formed the foundation for the overall promise of the patent. The Federal Court concluded that at the time of filing, there was no sound or articulable line of reasoning that would have led the inventors (from the evidence available at the relevant time) to make the explicit promise of the substantial advantage.

When the Federal Court decision was appealed to the SCC, the SCC denied leave to appeal, perhaps because the Court felt the issue was best left to the legislature to clarify. However, given the confusion surrounding the doctrine and the fact that it has resulted in a higher utility threshold requirement in Canada than in the US and the EU, the time has come for the SCC to address the issue. On January 30, 2014, the SCC granted leave to appeal of the Plavix case.8

The Plavix Case

In the Plavix case, the trial judge found a patent to be invalid on the basis of inutility. The trial judge found that the patent contained an explicit promise regarding a specific result in humans. While the promise was soundly predicted, the trial judge held that the inventors had not disclosed enough of their factual basis and line of reasoning to satisfy the doctrine of sound prediction.

The Federal Court of Appeal (the “FCA”) attempted to provide some much needed clarification on the promise of the patent doctrine. Firstly, the FCA noted that “if an inventor does not make an explicit promise of a specific result, the test for utility is a mere [trace] of utility. If, on the other hand, the inventor makes an explicit promise of a specific result, then utility will be assessed by reference to the terms of the explicit promise.

The FCA attempted to clarify and add practicality to the promise doctrine by distinguishing between the potential use of an invention and an explicit promise to achieve a specific result. In other words, the FCA pointed out that judges should not try to read a promise into a patent where none exists. The FCA explained that Canadian patents are often based on European priority applications, which (unlike the requirements under Canadian patent law) are required to state in their disclosures how their inventions are capable of industrial application. Thus, the courts should take care to distinguish between statements made in the patent’s disclosure and statements of utility made in the claims. Finally, the FCA stated that “…Courts should not strive to find ways to defeat otherwise valid patents.”

Appeal to the SCC

The Plavix case has not yet been heard by the SCC but it is anticipated that the SCC will finally attempt to clarify the promise of the patent doctrine as well as provide useful guidance on what the threshold actually is for establishing utility. Given the policy considerations outlined above, the SCC may discuss whether Canada should continue to have a higher threshold requirement to show utility than other foreign jurisdictions.

The SCC decision regarding the assessment of the “promise doctrine” will, no doubt, have a considerable impact on pharmaceutical patents but will also impact all other industries, albeit to a lesser extent. Quite possibly, the decision may yield a test for determining the promise of a patent as it did, more than a decade.



1 Patent Act, RSC 1985, c P-4, s 2.

2 Consolboard Inc v MacMillan Bloedel (Sask) Ltd, [1981] SCR 504.

3 2011 FCA 83

4 2013 FCA 219

5 Apotex Inc et al v Wellcome Foundation Ltd, 2002 SCC 77 at para 70.

6 Apotex Inc v Wellcome Foundation Ltd, 2002 SCC 77 at para 66. [AZT]

7 Eli Lilly Canada Inc v Novopharm Ltd, 2012 FCA 232.

8 Apotex Inc v Sanofi-Aventis, 2011 FC 1486 [Plavix].