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Supreme Court of Canada to Consider “Promise of the Patent” Doctrine

The law relevant to the utility requirements for patentability has frequently been the focus of litigation in Canada in recent years. This has been particularly so with respect to pharmaceutical patents, with several such patents covering different drugs being found by Courts to be invalid for lack of utility. However, it was not that the drugs involved were in fact useless. To the contrary, the drugs had been approved for sale and use by patients in Canada, and were undeniably valuable. In many cases, the drugs were very successful. Indeed, it was their success in the marketplace that attracted the attention of generic competitors who challenged the relevant patents to access a lucrative market. The patents involved were found to lack utility because the patentee could not prove in the litigation that the utility "promised" by the patent had been either "demonstrated" or "soundly predicted"1 as of the Canadian patent application filing date. The utility found promised was often a therapeutic utility in humans, explicitly referenced in the patent disclosure but not in the relevant claims. As clinical studies had not yet been completed by the filing date (as one would expect in the highly regulated pharmaceutical environment), the promised utility had not by that date been demonstrated. The in vitro or in vivo testing data available to the patentee as of the same date also failed to establish the relatively high standard of whether the therapeutic utility was soundly predicted. Often, amongst the existing corresponding patents in commercially important jurisdictions, it was only in Canada that the patent was found invalid for lack of utility.

In this context, Canada's highest Court, the Supreme Court of Canada (SCC), agreed in March of this year2 to hear an appeal in a pharmaceutical patent case on the issue of what is the correct applicable standard for patent utility in Canada, and in particular, whether a "promise of the patent" utility doctrine (Promise doctrine) properly exists. The appeal is tentatively scheduled to be heard on November 8, 2016.

Background and the 653 Patent (esomeprazole)

Apotex, interested in being able to market a generic version of NEXIUM (esomeprazole), challenged the validity of AstraZeneca's Canadian patent No. 2,139,653 (653) on numerous grounds including lack of utility. Of the following 653 patent claims, AstraZeneca relied only on claim 8 in asserting infringement by Apotex.

8. A compound (esomeprazole)…. having an optical purity of 99.8% or greater.

26. Use of an optically pure (esomeprazole)…. for inhibiting gastric acid secretion.

28. Use of an optically pure (esomeprazole)…. in the manufacture of a medicament with a lower degree of interindividual variation in plasma levels.

29. Use of an optically pure (esomeprazole)…. in the manufacture of a medicament with an improved therapeutic profile when treating gastric acid related diseases.

The 653 patent disclosure includes the following statements:

Omeprazole and its alkaline salts are effective gastric acid secretion inhibitors, and are useful as antiulcer agents. The compounds, being sulfoxides, have an asymmetric center in the sulfur atom, i.e. exist as two optical isomers (enantiomers). 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.

Federal Court (FC)3

"....the promise of the patent is the yardstick against which utility is measured….if a patent makes a promise, it will have utility only if that promise is fulfilled."

Following a trial, the FC construed claim 8 to be a compound claim and that its essential elements did not include any improved properties or therapeutic profile. Claim 8 so construed was found to be novel and inventive. Apotex's anticipation and obviousness attacks were therefore rejected. However, in respect of Apotex's utility attack, the FC characterized the applicable legal principles as follows:

(85) The utility analysis is intimately connected to the determination of the promise of the patent. Indeed, the promise of the patent is "fundamental to the utility analysis"….

(86) Conceptually, the promise of the patent is the yardstick against which utility is measured. Put differently, requiring that a patent be useful begs the question: "useful for what?" The answer to that question is the promise of the patent….. Thus, if a patent makes a promise, it will have utility only if that promise is fulfilled.

(87) Identifying the promise of the patent requires a consideration of "the patent as a whole" …. Claims construction, in contrast, only considers the disclosure for broader context and to resolve ambiguities…

The FC found the patent promised that its compounds (including the (+) enantiomer which was not claimed) provide improved pharmacokinetic and metabolic properties which will give an improved therapeutic profile, such as a lower degree of interindividual variation. As that utility had not been demonstrated nor soundly predicted as of the filing date, the entire patent was found invalid, even though it was not in dispute that esomeprazole would have been accepted to be useful as a proton pump inhibitor as of the filing date.

However, in a departure from existing jurisprudence on the requirements for a sound prediction, the FC found that "the requirement for proper disclosure of utility is limited to the context of "new use" patents, assuming such a utility disclosure requirement exists at all. As a consequence, I would rule that the failure of AstraZeneca to disclose the studies it relies upon for a sound prediction in this case would be irrelevant because the '653 patent is not a new use patent".

Federal Court of Appeal (FCA)4

In dismissing AstraZeneca's appeal, the FCA did not find any reviewable error in the FC's analysis and decision on the Promise doctrine, based on existing jurisprudence. The FCA specifically rejected AstraZeneca's submission that "it is a fundamental rule of claim construction that a claim receives one interpretation for all purposes, there must be a unitary, harmonious understanding of the essential elements of the claim, inventive concept and utility".

SCC Pending Appeal

Review of the utility requirements for patentability by the SCC is timely, given that its previously expressed interest in the issue in another case was precluded by the appellant's discontinuance5. In addition, with the passage of time, the number of cases involving the Promise doctrine has grown, highlighting the material difference between the utility requirements in Canada compared to its important trading partners, including the US and EU, which do not have such onerous requirements. Furthermore, the most recent jurisprudence has two FC judges disagreeing6 with the trial judge in the esomeprazole case with respect to whether there is properly a disclosure requirement for the sound prediction test.

Consequently, pharmaceutical innovators and their generic competitors are all closely following the pending SCC appeal in the esomeprazole case, in which a decision may be available by the spring of 2017.

Gunars A. Gaikis is a partner of Smart & Biggar/Fetherstonhaugh

  1. The doctrine of sound prediction, as stated in Apotex v. Wellcome 2002 SCC 77, has three components: (i) there must be a factual basis for the prediction; (ii) the inventor must have at the date of the patent application an articulable and "sound" line of reasoning from which the desired result can be inferred from the factual basis; and (iii) there must be proper disclosure. Subsequent jurisprudence determined that the proper disclosure must be in the patent as understood by the skilled reader applying the common general knowledge.
  2. SCC case number 36654
  3. Citation: 2014 FC 638
  4. Citation: 2015 FCA 158
  5. The SCC had previously granted leave to appeal to Apotex in a case involving the utility issue in respect of PLAVIX (clopidogrel). Apotex discontinued its appeal the day before the SCC appeal hearing scheduled for November 4, 2014.
  6. Eli Lilly v Hospira 2016 FC 47 at 49 and Allergan v Apotex 2016 FC 344 at 57.