On November 8, 2016 the Supreme Court of Canada (“SCC”) heard an appeal by Astrazeneca regarding the validity of a patent covering its NEXIUM product.[1] At trial and before the Federal Court of Appeal, Apotex successfully argued that Astrazeneca’s patent was invalid for lack of utility on the basis of a failure to demonstrate or soundly predict the promised utility as of the patent’s filing date. At issue before the SCC was the legitimacy of the so-called “Promise Doctrine”, as well as the proper approach to take in evaluating whether a claim meets the Patent Act’s utility requirement.[2]

The legitimacy of the Promise Doctrine was raised years earlier when the SCC granted leave on this issue in Plavix[3], only to have Apotex discontinue its appeal on the day before the hearing. In seeking leave to appeal and in its written materials, Astrazeneca focused on both the legitimacy of the Promise Doctrine and the approach to be taken in considering utility. However, in oral argument, counsel for Astrazeneca’s argument focused little on the Promise Doctrine’s legitimacy and heavily on the approach to be used in considering utility. Below is commentary on the Promise Doctrine, including its historical basis and its importation into Canadian law without statutory enactment.

What is the Promise Doctrine?

In Canada, the Federal Court and the Federal Court of Appeal have routinely stated that “a scintilla of utility” will suffice to meet the section 2 statutory requirement of “useful”.[4] Until the jurisprudence changed (around 2005 in the Federal Court[5]), a claimed invention only needed any utility to be useful and meet the statutory requirement in the Patent Act. However, starting in the mid-2000s the Courts started reading in promised utilities into claims based on statements in the patent disclosure.

For example, in the Accupril case, the Court found that the compound claims 3 and 5 attached to a promise to treat hypertension. These claims did not specify the purpose for which the compounds were to be used.[6] For a claim to a compound, the requisite utility had previously been a mere scintilla, but in this case, it was now required that the compound provide treatment of a medical condition because of its activity as described in the disclosure.

Thus a jurisprudential wedge on utility in the Federal Court arose.

The myriad of decisions that followed led to confusion and uncertainty, some cases overlaying one or more statements from patent disclosures into the claims, other cases declining to do so.[7] The Federal Court of Appeal attempted to rationalize the law by confirming that a scintilla of utility meets the statutory requirement for utility and finding that any further requirement of utility is only to be found where the Court has found an explicit promise of a specific result in the patent specification.[8] Then the Court has required that the patentee show that the promise(s) was/were demonstrated or soundly predicted as of the patent filing date.[9] Unfortunately, some Courts have confused some statements of advantages or preferences of a claimed invention with explicit promises.

In the Esomeprazole case, multiple statements or promises were found from the patent specification, and a failure to demonstrate or soundly predict one or more of those promises sufficed to invalidate the patent claims at issue.[10]

In considering sound prediction, some decisions from lower courts have imposed the requirement that the support for the sound prediction must also be disclosed in the patent[11] where it is not part of the skilled person’s common general knowledge, even though the SCC has stated that utility is considered separate and apart from the section 27(3) disclosure requirements of the Patent Act in Viagra.[12]

Thus, the Promise Doctrine created – without any statutory enactment – three additional requirements for “usefulness” in Canadian law as follows:

  1. The tying of statements made in a patent to a “promised utility”;
  2. The requirement that the promised utility be demonstrated or soundly predicted as of the filing date of the Canadian patent application (rather than simply that the claimed invention be useful in fact); and
  3. The requirement that the factual basis and line of reasoning for a sound prediction be disclosed in the patent.[13]

Traditionally, utility was a straight-forward requirement for patentees to understand and meet. The “utility” requirement was meant to keep “useless” inventions out of the public domain; an oft-cited example is a perpetual motion machine. So, the utility requirement was satisfied so long as a claim was not devoid of utility, that is, so long as a claim had at least a “scintilla” of utility, or was capable of industrial application.[14]

The Promise Doctrine has fundamentally changed this standard. It is no longer enough that a claim be useful (even though this is the statutory requirement of the Patent Act). Rather, the three-pronged approach of the Promise Doctrine has been used to invalidate dozens of patents since around the mid-2000s. Under the traditional approach to utility, less than five patents were found invalid for lack of utility from 1980 to 2004. From 2005 onwards, more than 25 patents have been found invalid for lack of utility. Of these post-2004 invalidations, almost every patent has claimed subject matter that was in fact useful. Even if one adopts the arguably higher European standard of “capable of industrial application”, these claimed inventions, as embodied in commercial products covered by the invalidated patent claims, were in fact useful.

Where did the Promise Doctrine Originate?

Courts routinely cite Consolboard v MacMillan Bloedel for the proposition that a patent will be invalid if it makes a promise that is not demonstrated or soundly predicted by the filing date.

There is a helpful discussion in Halsbury’s Laws of England, (3rd ed.), vol. 29, at p. 59, on the meaning of “not useful” in patent law. It means “that the invention will not work, either in the sense that it will not operate at all or, more broadly, that it will not do what the specification promises that it will do”.[15]

However, the quote from Consolboard must be understood in context. In particular, this passage was based on the U.K. Patent Act and its provision on “false suggestion or representation”:

  1. that has since been repealed;
  2. that was removed from Canada’s Patent Act in 1869 in favour of what is now section 53(1);
  3. that required any promise to be “material and coterminous” with the claims; and
  4. that was not tied to the filing date of the patent – the determination of whether the inventors made a false promise was considered as of the hearing date.

The U.K. Law was Repealed in 1977

The Consolboard passage relies on old U.K. law that was repealed in 1977. Prior to 1977, the U.K’s Patent Act contemplated patents being found invalid in situations where “the patent was obtained on a false suggestion or representation.”[16] It is significant to note that in this old U.K. provision that there was no temporal requirement of establishing a false promise by the patent filing date. The relevant date was the date of hearing. One must also remember that the representation or suggestion by which the patent was obtained had to be a false one. Otherwise, the cause of action to impeach the patent failed.

In 1977, the U.K. provision was repealed and thus there is no doctrine of false promise in the U.K. today.

For there to be a promise doctrine applicable to Canadian patents, there must be a statutory basis in Canada’s Patent Act. The SCC has oft-stated that a patentee can rely on the Patent Act and that a patent will thus only be granted if the patent requirements are met or invalidated when the requirements of the Act are not met. A pithy statement to this effect was made in Hoechst where Judson J. stated that “there is no inherent common law right to a patent. An inventor gets his patent according to the terms of the Patent Act, no more and no less.”[17] Thus, the tying of the level of utility to promises made in a patent would be permissible if supported by the utility requirement in the Patent Act.

Canada’s Patent Act Dropped False Promise in 1869 in Favour of Section 53(1)

The predecessor to Canada’s Patent Act once contained a provision relating to false promise that was similar to the false promise provision that was removed from the U.K. Patent Act in 1977. In particular, the Patent Act of the Province of Canada, 1849, provided for the impeachment of a patent that was “fraudulently or surreptitiously obtained, issued improvidently, or upon false suggestion…it shall and may be lawful for any person desirous to impeach such Letters Patent for any such cause as aforesaid”. [emphasis added][18]

However, Parliament repealed this provision in 1869 in favour of what is now section 53(1) of the Patent Act. Section 53(1) states:

A patent is void if any material allegation in the petition of the applicant in respect of the patent is untrue, or if the specification and drawings contain more or less than is necessary for obtaining the end for which they purport to be made, and the omission or addition is wilfully made for the purpose of misleading.

Thus, Parliament removed “false suggestion” as a ground for patent impeachment in favour of section 53(1), which requires an element of wilfulness[19] and which is evaluated as of the date of issue,[20] not the filing date. Contemporaneous commentary by Biggar noted the significance of this change:

In the result, it can only be said that, having regard to the terms of both the sections referred to [the versions of subsections 53(1) and (2) in force at the time], it would appear that the careless or inexpert draftmanship of a specification probably has less severe consequences in Canada than in either Great Britain or in the United States. The decisions of courts in these jurisdictions which turn on the making of unduly broad claims, upon the incompleteness of the specification, or upon inaccurate statements in it, are to be applied in Canada with the utmost caution when the incompleteness or the inclusion of the unduly broad claims or the inaccurate statements does not appear to have been due to an intention to mislead.[21]

Thus, there is there no statutory basis in Canada’s Patent Act for an invalidation on the basis of false promise. Such a basis did exist, but Parliament explicitly repealed it in favour of a different approach.

Material and Coterminous

As a further error in evaluating the level of utility under the guise of promise, some Canadian courts have expanded Consolboard/Halsbury’s to statements in the disclosure that go beyond the claimed subject-matter. The U.K. law on which Consolboard relied would only find a promise to be useable as a basis to invalidate a patent when the promise was “material and coterminous” with the patent’s claims, and was actually false, not unproven as of the filing date.[22]

Some Canadian decisions have tied any “promises” made in a patent’s disclosure to certain claims with which such statements correspond.[23] However, other decisions have taken statements from the disclosure and found them to be overarching promises that apply to all claims.[24] Thus, Canadian courts have not only imported a foreign doctrine which has no basis in Canada’s (or the foreign country’s current) Patent Act, but also, in certain cases have expanded the doctrine and applied it to all claims of a patent, even where the “promise” made is not material and coterminous with those claims, and is not necessarily “false”.

Consolboard Dealt with Utility in Fact – it was Not Tied to the Filing Date

Even if it were proper to evaluate utility in Canada based on “promises” made in a patent’s specification (despite there being no statutory basis), the Promise Doctrine is further offside Consolboard because it requires an evaluation of utility as of the filing date of the Canadian patent application. The law in Canada, the U.S., and the U.K. was harmonious in allowing post-filing data to be used to establish utility, and this was the framework under which the Court in Consolboard was operating. It is also the understanding in the Halsbury’s text used as support for the Consolboard statement. In particular, Halsbury’s states:

Meaning of not useful. Not useful in patent law means that the invention will not work, either in the sense that it will not operate at all or, more broadly, that it will not do what the specification promises that it will do. If the invention will give the result promised at all, the objection fails. [emphasis added][25]

These statements are all in the present tense. Halsbury’s does not call for an investigation as to whether the utility was established as of the filing date; it is solely oriented to whether there was utility in fact. However, Canadian courts have created another non-statutory requirement that utility be evaluated as of the filing date for promises made, predicted, and demonstrated in order to meet the meaning of the statutory term “useful”.


The only issue that the SCC need consider in Esomeprazole is whether the Promise Doctrine is legitimate under Canada’s Patent Act. Patent law in Canada is wholly statutory, and there is no statutory basis in Canada for the Promise Doctrine. Therefore, the SCC should have heard that Promise doctrine has no legitimacy under the Canadian Patent Act as currently enacted.

Indeed, Parliament chose to repeal the statutory basis for the doctrine in 1869. The reliance on the short Consolboard passage by Canadian courts is misplaced. An investigation into the basis of this passage (namely, the 1949 U.K. Patent Act and the Halsbury’s text cited in Consolboard) shows that there is no basis for the doctrine in Canadian (or current U.K.) law. If the doctrine has any place in Canadian patent law, evaluation of a “promise” is to be done as of the hearing date.

If the Promise Doctrine is not legitimate and has no statutory basis under the Patent Act, there is no need to further elaborate on the requirements for utility. The SCC has done so numerous times in the past in holding that a patent will lack utility where it is devoid of utility in fact, evaluated as of the hearing date. A return to this standard would increase certainty for litigants and ensure that undisputedly useful inventions do not continue to be invalidated for lack of utility in Canada.