What does “useful”, one of the basic requirements for the patentability of an invention, mean in Canadian patent law? On June 30, 2017, in AstraZeneca Canada Inc. v. Apotex Inc. (AstraZeneca), the Supreme Court of Canada (SCC) ruled that the threshold for utility is low — a mere scintilla will do. In fact, requiring anything more is not only overly onerous; it is incongruent with the Patent Act and antagonistic to the bargain theory on which patent law is based.

PROMISE AS PART OF PATENT BARGAIN

To be eligible for a patent, the law requires that an invention must be, among other things, new, useful and non-obvious. Should a new, useful and non-obvious invention be denied patentability because a patent application and the resulting patent include a superfluous statement as to a specific level of utility that is not fulfilled at the time the application was filed?

The “bargain theory” of patent law is based on the grant to an applicant of the exclusive rights in an invention for a limited period of time in consideration for disclosure of the invention to benefit society. In recent years, a statement of utility in a patent has been considered a “promise”, forming part of the bargain. If a promise extended beyond that which could reasonably have been understood as a hoped for advantage at the time of filing the application, the patent was held invalid for a lack of utility. This is no longer the case.

In AstraZeneca, in a unanimous ruling, the SCC struck down what had come to be called the “promise doctrine” as “unsound”. In doing so, the SCC reversed years of judge-made law and more closely aligned the utility requirement with that of most of the industrialized world.

THE PROMISE DOCTRINE

The requirement that an invention must be useful is enshrined in the definition of “invention” in the Patent Act (Act). But how is usefulness or “utility” assessed?

In a 1981 decision, instead of defining what utility is, the SCC defined what utility is not. The SCC said that there is a lack of utility if “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 [patent] specification promises that it will do“. It is the latter part of this statement that led to the promise doctrine.

Over the years, the Federal Court of Canada has interpreted and applied the above language to construe a statement in a patent that speaks of an advantage, directed to what the invention will or will not do, as a promise. This “promise of the patent [was] the yardstick against which utility [was] measured” and had to be either specifically demonstrated or soundly predicted at the filing date of the application. In Canada, unlike some other countries, evidence of events after the filing of the application is prohibited. Additionally, if a patent included multiple promises, each had to satisfy the utility requirement independently.

BACKGROUND

In the above action, Apotex sought to invalidate AstraZeneca’s patent for the commercially and functionally successful esomeprazole drug, sold under the NEXIUM trade-mark, comprising salts of one of the two mirror image molecules contained in the previously known mixture, omeprazole. Both drugs are used to decrease stomach acid and treat gastric reflux and related conditions; the difference being that the single molecule was found to work better than the mixture.

Apotex succeeded at trial on its argument that AstraZeneca’s patent included a promise of utility beyond a “hoped for advantage”. Specifically, the construed promise said that the new drug is more effective than the previously known mixture and provides less variation in patients’ response.

Esomeprazole did provide an improved therapeutic profile, which did lead to a lower degree of individual variation. However, AstraZeneca did not specifically know this at the time the application was filed and only became aware of it through clinical trials that took place later. The trial court held that, on a purposive construction, the patent as a whole did not provide a sufficient basis to soundly predict this result at the filing date. Therefore, the patent lacked utility and was invalidated. The decision was upheld on appeal.

The result in AstraZeneca was due in part to the fact that the patent was a “new use” case, in which the esomeprazole molecule was previously known and the foundation for the invention was the new (or improved) use. A new use patent is subject to an elevated disclosure requirement, which is meant to prevent an applicant from making an unverified promise to obtain a monopoly on an invention that, but for the promise, would be in the public domain. Importantly, however, even under this standard, if no promise was made in the specification, a “mere scintilla” of utility would have sufficed and the patent would stand.

NEW TEST FOR UTILITY

On further appeal, the SCC considered whether a patented invention that includes a statement that could be construed to be a promise should be required to satisfy that promise at the time of filing of the application.

The biggest challenge the SCC appeared to have with the promise doctrine was that the promise could be found anywhere in the claims or the patent’s description, although the claims alone are traditionally analyzed for the other requirements of patentability and the description is only considered when there is ambiguity in the claims. The SCC concluded that there is no basis in the Act for looking to the description to satisfy utility, and doing so conflates two distinct requirements (utility and disclosure).

The SCC abolished the promise doctrine and replaced it with another, simpler test of utility that requires determination of:

  • The subject matter of invention, as defined by the claims; and
  • Whether that subject matter is capable of use for a practical purpose.

The SCC noted that any degree of usefulness related to the purpose of the invention satisfies this requirement.

WHAT’S ALL THE FUSS ABOUT?

The only reference in the Act to utility is the reference to “useful” in the definition of “invention”. The promise doctrine appears to have gone far beyond this requirement. As the doctrine became entrenched, numerous patents for drugs were invalidated for an absence of utility despite the commercial success of the drugs.

The costs to the innovative pharmaceutical industry of dealing with the promise doctrine were significant. To illustrate, after two of Eli Lilly’s Canadian patents were invalidated by the promise doctrine, it initiated a C$500-million claim against the Government of Canada, alleging that the doctrine violated the intellectual property standards under the North American Free Trade Agreement (NAFTA). Although the NAFTA challenge failed, the value of challenging the promise doctrine demonstrates how significant the SCC decision on utility will be for patentees going forward.