The “Promise Doctrine” has been conclusively rejected by Canada’s highest court as a basis for invalidating a Canadian patent. In a judgment that reverses years of jurisprudence in the lower courts, the Supreme Court of Canada today held that the level of utility required of a Canadian patent must not be measured by statements in the specification. This judgment brings Canadian law more closely in line with that of our international trading partners and is a significant win for patentees and pharmaceutical innovation in Canada.

Case: AstraZeneca Canada Inc. v Apotex Inc., 2017 SCC 36 (SCC File No. 36654), rev’g 2015 FCA 158 (Court File No. A‑420‑14), aff’g 2014 FC 638 (Court File No. T-1668-10)

Drug: NEXIUM® (esomeprazole)

Nature of case: Appeal from declaration of invalidity in infringement/impeachment action under the Patent Act, RSC 1985, c P-4

Successful party: AstraZeneca Canada Inc., AstraZeneca Aktiebolag, and AstraZeneca UK Limited (AstraZeneca)

Date of decision: June 30, 2017


The Supreme Court’s holding comes in the context of a dispute regarding the validity of a patent for esomeprazole, which has been litigated extensively in the Federal Courts. Esomeprazole is a proton-pump inhibitor (PPI) used in the reduction of gastric acid, reflux esophagitis, and related maladies. AstraZeneca Canada Inc. markets esomeprazole in Canada as NEXIUM®, which is claimed in Canadian Patent No. 2,139,653 (the 653 Patent).

In each of the previous judgments on the validity of the 653 Patent, claims were declared invalid for failure to demonstrate or soundly predict “promises” of utility found in the specification. The main issue before the Court was whether, under the Promise Doctrine, these “promises” determined the standard against which utility should be measured.

Appeal allowed: The Promise Doctrine is an error of law

In unanimous reasons, the Supreme Court allowed AstraZeneca’s appeal and struck down the Promise Doctrine as an error of law.

Writing for the Court, Rowe J. emphasised the connection between utility and the subject-matter of the invention:

For the subject-matter to function as an inventive solution to a practical problem, the invention must be capable of an actual relevant use and not be devoid of utility.

With this in mind, Rowe J. held that utility must instead be assessed using the following two-step test:

First, courts must identify the subject-matter of the invention as claimed in the patent. Second, courts must ask whether that subject-matter is useful — is it capable of a practical purpose (i.e. an actual result)?

This new test is driven by the claims of the patent, rather than the description.

Justice Rowe also confirmed that there is a single, low bar for proof of utility, restoring the “scintilla” standard as the focus of the analysis:

The Act does not prescribe the degree or quantum of usefulness required, or that every potential use be realized — a scintilla of utility will do. A single use related to the nature of the subject-matter is sufficient, and the utility must be established by either demonstration or sound prediction as of the filing date[…].

In reaching this conclusion, the Court recognised that the Promise Doctrine was excessively onerous and inconsistent with the scheme of the Patent Act. By wrongly conflating the utility requirement in section 2 with the disclosure requirement in subsection 27(3), the Promise Doctrine had the potential to punish patentees for attempting to fulfill their part of the patent bargain by fully describing the invention and its use.

Declaration of invalidity reversed: The 653 Patent does not lack utility

Applying the correct test for utility, the Supreme Court held that the 653 Patent was valid and reversed the Courts below.

In the Federal Court, Rennie J. had held that the subject-matter of the 653 Patent was “optically pure salts of the enantiomer of omeprazole”. He had also held that one of the utilities identified under the promise doctrine — that these salts would be useful as PPIs to reduce the production of gastric acid — had been soundly predicted by the relevant date.

These holdings were sufficient to support the utility of the 653 Patent: the other promises the lower courts had found in the specification were irrelevant to the utility analysis.

Procedural history

Following the dismissal by Hughes J. of a prohibition application by AstraZeneca under the Patented Medicines (Notice of Compliance) Regulations in 2010, Apotex launched a competing esomeprazole product in Canada. This formed a basis for the underlying action, in which AstraZeneca sued Apotex Inc. and Apotex Pharmachem Inc. (Apotex) for infringement of the 653 Patent.

Apotex defended the action in part by counterclaiming for a declaration of invalidity. In 2014, Rennie J. (as he then was) found the 653 Patent invalid and dismissed AstraZeneca’s action for infringement. Although Rennie J. agreed with AstraZeneca that the claims of the 653 Patent were novel and non-obvious, he found that they were invalid for failure to demonstrate or soundly predict the promised utility of the patent.

As reported here, AstraZeneca appealed from the Court’s declaration of invalidity on the basis that the utility analysis contained a number of legal errors. Writing for a unanimous panel of the Court of Appeal in 2015, Dawson J.A. concluded that Rennie J. had correctly construed the promised utility of the claims in issue and dismissed the appeal. Today’s judgment is rendered on further appeal by AstraZeneca to the Supreme Court of Canada.

On the appeal, the Supreme Court heard oral argument from AstraZeneca and Apotex, as well as the following interveners: Innovative Medicines Canada and BIOTECanada (jointly); the Centre for Intellectual Property Policy; and the Fédération internationale des conseils en propriété intellectuelle. The Court also received written submissions from the Canadian Generic Pharmaceutical Association, the Intellectual Property Owners Association, and the Intellectual Property Institute of Canada.

Innovative Medicines Canada and BIOTECanada were represented on the appeal by Norton Rose Fulbright Canada LLP.


  • The Supreme Court’s decision can be found here.
  • The Federal Court of Appeal Decision can be found here; our summary of the Federal Court of Appeal decision may be found here.
  • The Federal Court decision may be found here.