On June 30, 2017, the Supreme Court of Canada issued its much awaited decision on the so-called “promise doctrine” of patent utility (AstraZeneca Canada Inc. v. Apotex Inc. 2017 SCC 36). As applied for many years, the promise doctrine had two parts: where the specification of a patent does not promise a specific result, a “mere scintilla” of utility is sufficient; but where the specification sets out an explicit “promise,” utility will be measured against that promise. The Supreme Court has now held that the promise doctrine is excessively onerous and ought to be discarded. In its reasons, the Supreme Court echoed its earlier decisions that emphasize the primacy of the language of the claims of a patent.

The patent in issue (the “653 Patent”) described and claimed esomeprazole, which is one of the two components (technically, enantiomers) of a previously known drug, omeprazole. The 653 Patent acknowledged that omeprazole and its alkaline salts were known to be effective gastric acid secretion inhibitors and hence were known to be useful as anti-ulcer agents. After stating that omeprazole and its salts exist as two enantiomers, the 653 Patent stated:

It is desirable to obtain compounds with 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.

At trial, the judge held that the supposed improved pharmacokinetic and metabolic properties and lower degree of inter-individual variation was a “promise” of the patent. After all, these were words put in voluntarily by the patentee, presumably with the intent that these words would assist in demonstrating that the separation of the known drug omeprazole into enantiomers having a specified purity was patentable. However, the evidence was that as of the relevant date for the analysis, the inventors had not demonstrated that esomeprazole had this improved therapeutic profile and, further, had no basis upon which to predict that esomeprazole would have the improved therapeutic profile. The trial judge accordingly invalidated the entirety of the patent for lack of utility. The Federal Court of Appeal upheld this decision in short reasons.

In allowing the patentee’s appeal, the Supreme Court of Canada held that the promise doctrine, as previously applied by the courts, is excessively onerous in two ways:

  1. it determines the standard of utility that is required of a patent by reference to the promises expressed in the patent; and
  2. where there are multiple expressed promises of utility, it requires that all be fulfilled for a patent to be valid.

The Supreme Court stated that the proper analysis for determining whether a patent discloses an invention with sufficient utility is two-fold. 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)?

The Supreme Court held that only a scintilla of utility was necessary, reasoning that the purpose of the utility requirement is to prevent the patenting of fanciful, speculative or inoperative inventions. The Court elaborated on this scintilla of utility, stating that “[a] single use related to the nature of the subject-matter is sufficient” for patentability. Presumably, this single use must be identified in the disclosure of the patent in some manner, although the Supreme Court did not specifically address this point.

For the drug at issue, the Supreme Court concluded, in five short paragraphs, that the necessary scintilla of utility existed; based on the knowledge of omeprazole and its therapeutic effect, it was soundly predicted by the relevant date that esomeprazole would be useful as a proton pump inhibitor to reduce the production of gastric acid.

In this decision, the Supreme Court stated that an analysis regarding issues of validity, such as novelty or non-obviousness, focuses on the claims alone, and only considers the disclosure where there is ambiguity in the claims. If that is indeed the case, then looking at the claims alone for utility would be a consistent approach. However, earlier decisions of the Supreme Court are more nuanced, stating, for example, that where the claim is to a bare chemical formula, reference to the disclosure may be necessary to determine inventiveness.

While this decision provides some clarity to the law, there is still much uncertainty regarding in what circumstances and for what purposes the courts can have recourse to the disclosure of the patent in assessing validity. For example:

  • Is recourse permissible for utility only in the case of ambiguity in the claims, as this decision would suggest?
  • Is recourse permissible where the utility of the subject matter of the claim is not apparent from the claim itself, such as in the case of a bare chemical formula?
  • Is recourse no longer permissible for the purpose of determining the inventive concept of the claim?

While some posit that challenges for lack of utility will cease to be made in view of this decision, those challenges may simply now be phrased using the Supreme Court’s words of fanciful and speculative inventions.