Findability of Prior Art

A couple of recent decisions have provided some clarity to what prior art can be relied on to show that a patent is obvious. One of the cornerstones of patent law is that a patent must be for an invention that is ‘inventive’ or ‘non-obvious’. This leads to the next question, “inventive” compared to what?

A car with a six-cylinder internal combustion engine may be inventive if all you have is a bicycle but may not be inventive if you already have a car with a four-cylinder internal combustion engine.

The Patent Act, in section 28.3, states:

28.3 The subject-matter defined by a claim in an application for a patent in Canada must be subject-matter that would not have been obvious on the claim date to a person skilled in the art or science to which it pertains, having regard to … (b) information disclosed before the claim date by [almost anyone other than the applicant] in such a manner that the information became available to the public in Canada or elsewhere. (emphasis added)

The Supreme Court has gone on to clarify that in order to determine whether a patent claim is obvious, one must, “Identify what, if any, differences exist between the matter cited as forming part of the ‘state of the art’ and the inventive concept of the claim or the claim as construed” (Sanofi, paragraph 67).

Subsequent court decisions have followed two paths:

  1. “state of the art” is information that is pertinent and locatable to the skilled person in the technology at issue;
  2. “state of the art” or “information” can be anything that is available to the public.

For example, on the first path, in Eurocopter v. Bell Helicopter Textron Canada Limitée, 2012 FC 113 citing Pfizer Canada Inc v Apotex Inc, 2007 FC 971, the Court said it is entitled to look at all the patents and other publications that a skilled technician would discover in a ‘reasonable and diligent search’ to determine whether the resulting ‘mosaic’ leads directly to the invention. In Novartis Pharmaceuticals Canada Inc. v. Teva Canada Limited, 2015 FC 770, the Court again followed the first path, “Teva argues that the Patent Act … no longer requires that the relevant prior art be discoverable on a reasonably diligent search – it merely has to be publicly available. … However, there is case law applying the usual “reasonably diligent search” criterion even after the enactment of s 28.3 … I see no reason to take a different approach here.”

More recently the second path has gained favour. Justice Locke when he was a trial judge raised doubts about the ‘diligent search’ jurisprudence in Pollard Banknote Limited v. BABN Technologies Corp., 2016 FC 883 asking, “should a skilled person be able to obtain a valid patent by simply searching a dusty corner of a public library for a document that describes a forgotten invention and making an obvious change to it?”

In Aux Sable Liquid Products LP v. JL Energy Transportation Inc., 2019 FC 581, the Court rejected the ‘diligent search’ requirement based on the language of Section 28.3 of the Patent Act: “For the reasons detailed above, I agree with Aux Sable’s position as to the effect of s 28.3 of the Act, i.e. that a prior art reference which was disclosed to the public, prior to the applicable date prescribed by s 28.3, forms part of the prior art for purposes of an obviousness analysis, regardless of whether the reference would have been locatable through a reasonably diligent search.”

In January, the Federal Court of Appeal, in a decision written by Justice Locke, said in Hospira Healthcare Corporation v. The Kennedy Trust For Rheumatology Research, 2020 FCA 30, it was an error of the trial judge to reject prior art on the basis of how difficult it would be to locate:

In light of section 28.3 of the Patent Act and the applicable jurisprudence and commentaries, I conclude that it is an error to exclude from consideration prior art that was available to the public at the relevant date simply because it would not have been located in a reasonably diligent search. The likelihood that a prior art reference would not have been located by a PSA may be relevant to consideration of step 4 of the obviousness analysis (whether differences between the state of the art and the inventive concept constitute steps which would have been obvious to the PSA) in that the uninventive PSA might not have thought to combine that prior art reference with other prior art to make the claimed invention. However, excluding prior art simply because it is difficult to find is problematic because it would result in the possibility of a valid patent on an invention that had, but for some non-inventive tweak, already been disclosed to the public. In my view, that is not what Canada’s patent regime is intended to permit. (emphasis added)

This result, that for the purposes of determining obviousness ‎the ‎“state of the art” or “information” can be anything that is available to the public,‎ also aligns the types of prior art that may be considered for obviousness with the prior at that may be cited for anticipation, under section 28.2 of the Patent Act.

The issue of discoverability may still be relevant to combining of or creating a “mosaic” of prior art references, and, as suggested in the quote above from Hospira, in ‘bridging’ any differences between the prior art references and the inventive concept by the skilled person but the Federal Court of Appeal has made clear that the obscurity of a reference should not be a basis for excluding it from analysis.

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