Lawyers, patent &
trademark agents

Patents & the Doctrine of Promised Utility in Canada

On November 8, 2016, the Supreme Court of Canada will hear a highly anticipated appeal respecting the controversial “promised utility doctrine” that has made it more difficult to secure valid patent protection in Canada over the last 10 years. The development of this doctrine by our courts has taken Canada out of step with other major countries and many argue that it is contrary to Canada’s treaty obligations which are intended to harmonize international requirements for patentability.

The appeal concerns the Federal Court decision in AstraZeneca Canada Inc., et. al. v. Apotex Inc., et al. which found that AstraZeneca’s patent for the drug esomeprazole was invalid because the patent failed to fulfill the utility promises made in the application as of the filing date of the application.


The basic requirements for a valid patent are:

  1. Novelty – the invention is new and has not been previously been publicly disclosed;
  2. Inventiveness- based on information available before the patent application was filed, the invention must not be obvious to a person skilled in the subject matter of the invention; and
  3. Utility-the invention must be a useful art, process, machine, manufacture or composition of matter or an improvement to one of these.

To satisfy the latter utility requirement, patent applications typically contain an explanation of the background of the invention to identify the need that is met by the new invention. This background often includes an explanation of why previously known technology failed to solve a particular problem and statements outlining how the invention is better or how it fills a previously unmet need.   

Historically, the utility requirement has been interpreted to mean that a valid patent cannot be obtained for something that does not work or that has no useful function. This was a pretty low standard, and as long as the invention had even a “scintilla” of usefulness, the utility requirement was satisfied.

Promised Utility Doctrine Developed by Courts

Courts are often asked to consider the validity of patents long after they have issued and are being used to protect monopolies which have become commercially valuable in the marketplace. Over the last decade, the Federal Court has started to closely scrutinize statements made many years earlier in patent applications about the goals of the subject inventions.

This has proven particularly problematic for pharmaceutical patents that include statements that the subject drug has increased efficacy or reduced side effects. Such statements may now be considered to be explicit promises of the particular utility of the invention (referred to as “promised utility”). If the promised utility is not demonstrated by evidence available in the patent application as of its original filing date, the courts may use this omission as a ground to invalidate the patent. The applicant cannot rely on evidence discovered later to maintain a valid patent.

Since patents are granted to the “first to file” and not to the first to invent, inventors often file patent applications as early as possible to ensure that a commercial advantage is not lost to a competitor who may be actively working to independently develop a similar invention. However, for pharmaceutical drugs, it can be difficult to present evidence of the exact usefulness of a drug based only on early stage research and animal testing. And, because of the legal limitations, the courts are often required to consider the promised utility of a drug without looking at the results of the extensive clinical trials undertaken before the drug was approved for the public. Although these tests may provide ample evidence of the promised utility, they often occur years after the patent applications were filed and cannot be relied upon to establish utility as of the patent’s filing date.

The International Context

Since 2005 more than twenty patents have been held invalid in Canada because the disclosure in the patent application failed to demonstrate or soundly predict a promised utility. Other countries are more lenient when considering “utility” as a requirement for a valid patent.

In the USA, it is sufficient if an asserted utility is “credible”. Examiners will treat a utility assertion as credible unless the logic underlying the assertion is clearly flawed or the facts on which the assertion is based are inconsistent with the logic underlying the assertion.

The European Patent Convention requires inventions to be “susceptible of industrial application”, which has been interpreted as the requirement that it can be made or used in any kind of industry.

Since pharmaceutical patents are routinely filed in multiple jurisdictions and each national application for a patent must be filed within strict time limits after the first application is filed, it is problematic for applicants to be held to varying standards of utility as of the filing date:

  • If they wait until convincing evidence is available to support the patent application, it may be too late. A competitor may file an earlier application to patent substantially the same independently developed invention and thereby stake a prior claim to the international market.
  • If they don't wait until convincing evidence is available to support the patent application, the resulting Canadian patent may be vulnerable to expungement under the “promised utility doctrine”.

Questions for Supreme Court

In the AstraZeneca case soon to be heard by the Supreme Court, the patent for the drug esomeprazole (NEXIUM) contained the statement that:

“It is desirable to obtain compounds with improved pharmacokinetic and metabolic properties which will give an improved therapeutic profile such as a lower degree of interindividual variation. The present invention provides such compounds, which are novel salts of single enantiomers of omeprazole.” [emphasis added]

The trial judge found that this statement was not merely a goal by which utility could be measured, but instead was a promise of the patented invention. The judge found that the evidence in the patent fell short of demonstrating or soundly predicting this promised utility and the entire patent was held invalid. An appeal to the Federal Court of Appeal was dismissed.  

The questions on appeal to the Supreme Court of Canada are:

(1) Whether the “promise” in patent of improved pharmacokinetic and metabolic properties for improved therapeutic profile was demonstrated or soundly predicted at the time the patent was filed?

(2) What is the correct applicable standard for patent utility in Canada?

(3) Whether a promised utility doctrine properly exists in Canada?

We look forward to a decision from the Supreme Court that will clarify the applicable standard for patent utility in Canada and, hopefully, harmonize with the standards applied in other jurisdictions for the benefit of all international patentees.