While courts have often warned that hindsight bias should be avoided when assessing whether a patented invention would have been obvious to the skilled person, the application of this principle can be challenging in practice.
Section 28.3 of the Patent Act provides that the subject matter of a claim in a patent application must not have been obvious to a person skilled in the art as of the claim date. When the validity of a patent is challenged on the basis of obviousness—which is the case in almost all patent cases where validity is at issue—Canadian courts apply the well-known four-part obviousness test established by the Supreme Court of Canada in Apotex Inc v Sanofi-Synthelabo Canada Inc1 Steps one to three involve identifying the state of the art, determining the inventive concept of the claim, and identifying the differences between the inventive concept and the state of the art. Step four is to assess whether the differences would have been obvious to the skilled person without knowledge of the claimed invention.
The Federal Court of Appeal, in Janssen-Ortho Inc v Novopharm Ltd,2 proposed a list of factors that can be considered at step four. The principal factors are:
- What body of knowledge and information would the ordinary person skilled in the art be expected to have, or to be reasonably able to obtain, as of the date of the alleged invention?
- What was the climate in the relevant field at the time the alleged invention was made?
- What motivation existed at the time the alleged invention was made to solve a recognized problem?
- What effort and time were involved? Were those efforts routine or were there many decisions involved?
In Janssen-Ortho, the court also identified so-called secondary factors that may be considered, such as the invention's commercial success and any awards it has earned.
Almost every Canadian court decision that has analyzed the validity of a patent on the grounds of obviousness initially acknowledges the impropriety of hindsight analysis. Justice Hugessen’s eloquent warning is often cited:
Every invention is obvious after it has been made, and to no one more so than an expert in the field. Where the expert has been hired for the purpose of testifying, his infallible hindsight is even more suspect. It is so easy, once the teaching of a patent is known, to say, "I could have done that"; before the assertion can be given any weight, one must have a satisfactory answer to the question, "Why didn't you?"3
However, avoiding the hindsight trap is much easier said than done. Judges must mentally place themselves back in time to the relevant date, and in the shoes of the person skilled in the art who is unaware of the invention. This is a challenging task in the context of a trial, which may be taking place many years after the invention was made, and which requires the judge to spend considerable time reading and analyzing the patent together with a collection of prior art curated by the defendant with the benefit of hindsight.
The danger of being inadvertently influenced by hindsight is particularly pronounced when dealing with simple inventions. The simpler a solution, the easier it is to explain; the easier it is to explain, the more obvious it can appear. However, the simplicity of an invention often reveals its inventiveness. If the solution was simple, what prevented competitors from proceeding in that direction? What other directions were taken by people skilled in the art at that time when they truly had no idea of the solution taught by the patent?
This article examines two strategies to proactively mitigate the influence of hindsight when assessing obviousness. We rely on insight from recent Canadian decisions and decisions from the United Kingdom and the United States, where some judges are re-evaluating how obviousness should be analyzed in order to avoid the hindsight trap.
Selecting balanced prior art and briefing experts in stages
Prior art cannot be cherry-picked. The Courts have repeatedly recognized that it is improper for an expert to specifically look for invalidating prior art. There is a material risk of hindsight analysis if the state of the art is considered to include only those documents similar to the patent in issue, or if the analysis begins with a search for prior art that contains specific elements of a claim and then involves a mosaic of the references found.4 Failing to consider the prior art in context is characteristic of a hindsight analysis.5
Similarly, experts should not base their obviousness analysis largely or solely on the strength of prior art references selected by counsel, as this also creates a material risk of hindsight analysis. A proper prior art review should include a search for all available relevant prior art whether or not it supports inventiveness. The prior art review should shed light on other possible pathways and ideas that point away from the patent solution.6
In some cases, even these approaches may not be sufficient to avoid the hindsight trap, as hindsight can be inadvertent or subconscious. To our knowledge, no Canadian judge has gone as far as Lord Justice Arnold, a well-known and respected English jurist and currently Judge of the Court of Appeal of England and Wales in suggesting a method to proactively address the risk of being influenced by hindsight. In one of his recent decisions, Lord Justice Arnold highlighted the benefits of instructing experts using a procedure from the psychological literature known as sequential unmasking.7
Typically, when experts are retained to provide their opinion, they are first provided with the patent and relevant prior art identified by the party or the party’s counsel. They analyze those documents, and potentially conduct research on their own to identify additional documents, before they start formulating their opinion, including their opinion about obviousness at the time of the invention. Using the sequential unmasking approach proposed by Lord Justice Arnold, experts would first be asked about the common general knowledge in a specific field, then they would be shown the prior art and asked questions as to what steps would be obvious in light of that prior art to resolve a given problem. Only after they have answered these important questions would they be shown the patent in question.8 Although this approach presents implementation challenges, it could significantly reduce the risk of hindsight bias in expert analysis and, consequently, in court decisions.
Focusing on the context at the time of the invention
In Apotex Inc v Bayer AG, Justice Sharlow suggested that “an allegation of obviousness may be weakened if the evidence does not explain, directly or by inference, why the claimed invention was not discovered by others.”9 We believe this line of reasoning merits further development. A thorough understanding of the technical and commercial context at the time of the invention can help mitigate the risk of inadvertent reliance on hindsight.
In the United States, there is a strong focus on what is called “objective indicia” in assessing obviousness. Objective indicia include factors such as the commercial success of the invention, whether the invention covers a long-felt but unresolved need in the market, the failure of competitors in the market to arrive at this solution, praise by others, unexpected results and expert skepticism.
Chief Judge Rader of the Court of Appeal for the Federal Circuit noted that “these objective guideposts are powerful tools for courts faced with the difficult task of avoiding subconscious reliance on hindsight.”10 These objective indicia are considered independent evidence of nonobviousness. They are often considered the most probative and cogent evidence of nonobviousness available to courts. American courts frequently state that these objective indicia allow them to “turn back the clock.” These objective indicia allow courts to situate the invention in the proper temporal and technical perspective, which is challenging to achieve considering that courts are presented with the invention fully diagrammed, aided in their understanding by experts in the field, and the obviousness analysis is typically made several after the invention is made and the patent has issued, such that the technical know-how in the field has sometimes greatly evolved.11
We believe Canadian courts should consider this approach. By placing a stronger emphasis on the objective indicia, the United States’ framework may more effectively avoid the hindsight trap by situating the invention within its proper context. While similar factors are considered in Canada, they are often not given as much weight.12
Concluding remarks
Technical advances, like much of human endeavour, often occur through incremental steps toward greater goals. These marginal advances may seem deceptively simple in retrospect, particularly when retracing the path already blazed by the inventor.
We believe it is important to protect these incremental improvements, as they collectively make a big difference. Protecting these incremental improvements requires a fair assessment of obviousness that carefully guards against the potential influence of hindsight on that determination.
References
1. 2008 SCC 61 (Rothstein J.)
2. 2007 FCA 217 at para 25 (Sharlow J.A.)
3. Beloit Canada Ltée/Ltd v Valmet Oy, 8 C.P.R. (3d) 289 (FCA, 1986) at page 295 (Hugessen J.A.) more recently cited in Medexus Pharmaceuticals Inc v Accord Healthcare Inc, 2024 FC 424 at para 153 (Pallotta J.)
4. Molo Design Ltd v Chanel Canada ULC, 2024 FC 1260 at para 300 (McHaffie J.)
5. See most recently Takeda Canada Inc v Apotex Inc, 2024 FC 106 at para 198 (Furlanetto J.)
6. Astrazeneca Canada Inc v Apotex Inc, 2015 FC 322 at para 231 (Barnes J.) see also Swist v Meg Energy Corp, 2021 FC 10 at paras 209-210 (Fothergill J.)
7. Akebia Therapeutics Inc v FibroGen Inc, [2020] EWHC 866 (Pat) at para 36 (Lord Arnold)
8. Akebia Therapeutics Inc v FibroGen Inc, [2020] EWHC 866 (Pat) at para 36 (Lord Arnold)
9. 2007 FCA 243 at para 25 (Sharlow J.A.)
10. Mintz v Dietz & Watson, 679 F.3d 1372 (2012) at page 1378 (Rader J.)
11. Mintz v Dietz & Watson, 679 F.3d 1372 (2012) at pages 1378-1379 (Rader J.)
12. In the context of a Canadian pharmaceutical patent case, with a parallel decision from the United States, Justice Hughes observed that the American law on obviousness is not very different from Canadian law while quoting excerpts of the parallel American decision that discussed objective indicia. He also explicitly acknowledged that the American decision is interesting and informative but not binding in any way: Allergan Inc v Canada (Health), 2012 FC 767 at paras 94 and 100.
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