Promise Me No Promises? The Five-year Anniversary Of The Supreme Court's AstraZeneca Decision

• Published date: 15 June 2022
• Subject Matter: Intellectual Property, Litigation, Mediation & Arbitration, Patent, Trials & Appeals & Compensation
• Law Firm: Gowling WLG
• Author: Mr Alex Gloor and Jenny Thistle

From 2005 to 2017, numerous Canadian patents were invalidated on the basis of an approach to patent utility termed the "Promise Doctrine." Requiring any statement of advantage in a patent specification to have been demonstrated or soundly predicted by the patent's filing date lest the entire patent be invalidated, the Promise Doctrine created uncertainty for patent holders and placed Canada's approach to utility out of line with international norms. However, in the June 2017 decision of AstraZeneca v Apotex¹ the Supreme Court of Canada settled the Canadian patent litigation landscape by unanimously holding that the Promise Doctrine had no statutory foundation and was "not good law". We look back at AstraZeneca and review its impact in the five years since its release.

What was the Promise Doctrine?

Section 2 of Canada's Patent Act²requires that an invention be "useful." No level of utility is prescribed in the Act, and traditionally utility was seen as a low bar - so long as an invention was not devoid of utility, the statutory requirement was found to be satisfied.³ Given this standard, it was rare for a patent to be invalidated on the basis of lack of utility.

Two primary events changed the dynamic in the early 2000s. First, the Supreme Court decision of Apotex v Wellcome⁴ in 2002 imposed a requirement that utility be demonstrated or soundly predicted as of the patent's Canadian filing date. Then, in 2005, drawing on a statement made in a previous Supreme Court decision which itself was drawing on what became repealed UK law,⁵ Canadian courts began to approach the utility question by asking whether any "promise of the patent" was demonstrated or soundly predicted by the filing date.⁶

This "uniquely Canadian" Promise Doctrine created a boon to those seeking to invalidate patents.⁷

The Promise Doctrine was particularly impactful as was often applied to invalidate an entire patent on the basis of an unsubstantiated "promise,"⁸ even if the statement did not relate to the subject-matter of each of the patent's claims. The Promise Doctrine also had the result of invalidating patents even to useful inventions, as having proven utility in one respect would be of no moment to a patentee if a different "promise" was not substantiated.

Both of these prospects were realized in the lower courts' decisions in AstraZeneca, where all claims of the patent at issue were initially invalidated despite the claimed subject matter being useful as a proton pump inhibitor. Fatal to the entire patent was the fact that a second disclosed promise of "an improved therapeutic profile such as a lower degree of interindividual variation" - which was not part of the language of any of the asserted claims - had not been established by the filing date.⁹

The AstraZeneca v Apotex decision

The Promise Doctrine met its demise in AstraZeneca. The Supreme Court held that the Promise Doctrine was "incongruent with both the words and the scheme of the Patent Act," "punitive," "antagonistic to the bargain on which patent law is based" and that it "undermines a key part of the scheme of the [Act]."¹⁰ The Promise Doctrine's primary faults were said to be: (1) that it conflated the utility requirement with a disclosure requirement by determining the utility standard by reference to promises expressed in the patent; and (2) that, where a patent contained multiple promises of utility, each needed to be fulfilled.¹¹

Not only did the Promise Doctrine serve to invalidate otherwise valid patents, but it discouraged fulsome disclosure from inventors and thus was inimical to the goals of the patent system as a whole.¹²

After disposing of the Promise Doctrine, the Supreme Court set out the correct approach to utility and applied this framework to the facts before it.

In clarifying the utility standard needed to meet the Patent Act's requirement, the Supreme Court held that a demonstration or sound prediction of a scintilla of utility related to the nature of the subject-matter of the claims of the patent is sufficient.¹³Applying this, that the subject matter claimed in AstraZeneca's patent¹⁴ was soundly predicted to be useful as a proton pump inhibitor meant that the statutory criteria was met. That...