L'art antérieur et la brevetabilité
au Canada (en anglais)

This practice notice was originally published in Practical Law, part of Thompson Reuters Canada Limited, on July 1, 2023.

A Practice Note addressing prior art and patentability in Canada, which affects the scope of protection of any patent granted in Canada. This Note provides information useful for patent counsel with responsibility for a global patent portfolio to help them understand the legal analytical framework in Canada for determining the potential patentability of an invention, which a patent applicant may seek to cover. It provides guidance for determining whether a reference document or activity qualifies as prior art in Canada and addresses the novelty requirement, which is assessed through the test for anticipation and obviousness based on the scope of the prior art available in Canada.

When conducting patentability and validity evaluations, global patent counsel must often determine whether a reference document or activity qualifies as prior art. This determination is difficult because patent counsel must apply the law to different situations and even slight differences in a country's patent laws can have a significant impact on the final patentability and validity conclusion.

This Note discusses important considerations for determining whether a reference document or activity qualifies as prior art and the potential patentability and validity in Canada of a claimed invention over the prior art. It also addresses novelty and non-obviousness in connection with both patentability and validity evaluations.

It explains Canada's prior art law, identifies the key dates for determining if a reference document or activity is prior art to a patent application or issued patent (patent document), and describes the analytical framework for evaluating a claimed invention's patentability and validity in view of the prior art. This Note also discusses practical considerations for global patent counsel when developing a global patent portfolio and evaluating global freedom to operate searches.

Prior Art

The types of patent documents and non-patent literature (reference), and activities that can constitute prior art against a Canadian patent application are outlined in sections 28.2 and 28.3 of Canada's Patent Act, RSC 1985, c P-4 (Patent Act). Although not exclusively prior art provisions, sections 28.2 and 28.3 govern Canada's approach to novelty, determined under the test for anticipation, and non-obviousness, respectively.

Importantly, Canada places no blanket restriction or limitation against the types of references or activities that can be considered prior art in an anticipation or obviousness analysis. Instead, sections 28.2 and 28.3 require the reference or activity of interest to meet certain criteria before it can be considered prior art. If these criteria are met, the reference or activity can be considered prior art in an anticipation and/or obviousness analysis. An example of the criteria that sections 28.2 and 28.3 require is an analysis of when the reference or activity was made "publicly available" (see Prior Art Documents).

Dates for Prior Art Determinations

For a reference or activity to be considered prior art in either an anticipation or obviousness inquiry in Canada they must meet the criteria specified in sections 28.2 and 28.3 of the Patent Act, respectively. The criteria specified in these provisions include considering:

• The effective filing date of a claim in the relevant patent document (see Claim Date).
• The relevant dates that the reference or activity (potential prior art) must have been disclosed to the public to be considered to be prior art (disclosure deadline) (see Disclosure Deadline)

In Canada, potential prior art includes any disclosure made both:

• By a person who is not either the applicant or a person who obtained knowledge directly or indirectly from the applicant.
• Available to the public either in Canada or elsewhere in the world before a patent document's claim date.

However, where disclosure to the public was made either by the applicant, or by a person who obtained knowledge directly or indirectly from the applicant, an applicant has one year from the date of disclosure to file their application. Provided the claim date is within one year of the disclosure being made available to the public either in Canada or elsewhere, that public disclosure of the claimed invention will not be considered in either an anticipation or obviousness analysis.

Section 28.2 of the Patent Act also specifies a third scenario only applicable to an anticipation analysis. In light of Canada's "first to file" regime, no valid patent claim can be issued where:

• The claimed subject matter is already disclosed in another person's previously filed Canadian patent document.
• That other patent document has a claim date that precedes the claim date of the subject claim in question.

In this situation, the patent document can be a pending patent application that has not yet been made available to the public (or even the inventor) and still be considered anticipatory of the subject claims.

Claim Date

The claim date of a patent document is the relevant date to examine when evaluating whether potential prior art has met their specific disclosure deadline. The calculation of a patent document's claim date is governed by section 28.1 of the Patent Act. Under section 28.1, the claim date is either the patent document's Canadian filing date, or, where priority is validly claimed, the priority date.

To validly claim an earlier priority date, and have the priority date apply to one or more of the claims within a later-filed Canadian patent document, the following criteria must be met:

• The subject matter of the claim in the later-filed Canadian patent document must have been previously disclosed in a patent document filed by the applicant or their legal representative or predecessor in title.
• The earlier patent document has been filed in either Canada or in a country signatory to a relevant treaty also signed by Canada, such as any country that belongs to the Paris Convention for the Protection of Industrial Property Rights or a World Trade Organization Member Country.
• The filing date of the earlier patent document is within 12 months of the filing date of the later-filed Canadian patent document.
• The applicant must have made a request for priority.

Entitlement to an earlier priority date is based on the patent document's disclosed subject matter. Therefore, if a later-filed patent application includes new material that was added to the description and claims of the earlier-filed patent application, claims incorporating that new material may not be entitled to the earlier filing date as a priority date. In that case, the various claims contained in the later-filed patent application may have two different claim dates:

• The actual Canadian filing date of the later-filed application for claims incorporating the new material.
• The earlier priority date for claims without the new material.

Finally, Canada is a contracting member to the Patent Cooperation Treaty (PCT) and a PCT application can form the basis for the Canadian national phase application's claim date.

Under paragraph 28.2(1)(d) of the Patent Act, the claim date of other patent applications is also relevant when considering which co-pending Canadian patent applications can be considered in an anticipation inquiry. In addition, even where the Canadian filing date of the co-pending application is later than both the filing date and the claim date of the application in question, the co-pending application may still be anticipatory if it has a claim date that precedes the applicant's claim date.

Disclosure Deadline

All potential prior art, references, and activities must have been publicly available before either:

• One year before the claimed invention's effective filing date if the potential prior art was disclosed by the applicant or another who obtained knowledge from the applicant.
• The claimed invention's actual Canadian filing date if the potential prior art was not disclosed by the applicant or another who obtained knowledge from the applicant.

Typically, for non-patent references, the disclosure deadline is determined based on the publication date of the reference.

Prior Art Documents

Canada does not place a type-based limitation on what references can be included in either an anticipation or obviousness analysis. Instead, in sections 28.2 and 28.3 of the Patent Act, specify certain criteria that the reference must meet before it can be considered prior art.

Aside from the criteria specific to deadlines, the only other criteria specified in sections 28.2 and 28.3 is that a reference must be disclosed "in such a manner that the subject-matter became available to the public in Canada or elsewhere" before its disclosure deadline. The exception to this is with respect to other Canadian patent applications in an anticipation inquiry. (See Dates for Prior Art Determinations.)

This "publicly available" requirement applies to all types of references, including patents, patent applications and non-patent literature, whether published in Canada or elsewhere in the world, whether in printed, digital, or any other format and in any language. The question of public disclosure is an objective one. What matters is not whether a member of the public actually saw the reference, but whether the public had the opportunity to access the reference. For the public to have access to the reference, a person free at law and in equity to use the information must have access to it. Information disclosed on a confidential basis or in circumstances giving rise to an implicit duty of confidentiality would not be considered publicly available (Wenzel Downhole Tools Ltd v National-Oilwell Canada Ltd, 2012 FCA 333 at paras 23, 124, 126 (Wenzel)). Examples of publicly available references include:

• Published patents and patent applications.
• Non-patent literature, such as references posted online or in a non-digital format.
• Meetings, catalogs, and regulatory documents as long as the public who can access the reference is free at law and equity to use the information contained within it.

However, private manuscripts that are not publicly available or papers kept in cabinets or archives not normally accessible to the public would not be considered objectively "available to the public" (Wenzel at paras 124, 126, and 144). Indeed, as discussed in Baker Petrolite Corp. v Canwell Enviro-Industries Ltd, 2002 FCA 158 at subpara 42(6):

Further it is settled law that there is no need to prove that anybody actually saw the disclosure provided the relevant disclosure was in public. Thus an anticipating description in a book will invalidate a patent if the book is on a shelf of a library open to the public, whether or not anybody read the book and whether or not it was situated in a dark and dusty corner of the library. If the book is available to the public, then the public have the right to make and use the information in the book without hindrance from a monopoly granted by the State (emphasis in original).

Prior Art Activities

Prior activities can also be considered disclosures for the purposes of an anticipation or obviousness inquiry. The form of the disclosure is irrelevant under sections 28.2 and 28.3 of the Patent Act. Examples of activities that can be considered potential prior art in either an anticipation or an obviousness inquiry include:

• Information communicated orally to a member of the public.
• Prior use.
• Prior sale.
• A naturally occurring product.

(See for example Amgen Canada Inc v Apotex Inc, 2015 FC 1261 at paras 67-80.)

As is the case for prior art references, in order for a prior art activity to be considered in an anticipation or obviousness analysis, the activity must have been disclosed "in such a manner that the subject-matter became available to the public in Canada or elsewhere" before its disclosure deadline. Where a confidential relationship exists, there is no public disclosure (Weatherford Canada Ltd v Corlac Inc, 2010 FC 602 at para 316, rev'd in part 2011 FCA 228 at paras 36—65; Weatherford Canada Ltd v Corlac Inc, 2011 FCA 228 at paras 47—52).

In the case of a prior oral communication, public disclosure can occur where information has been orally communicated to a member of the public who is free to use the information as they please (Wenzel, at paras 129-131). Similarly, when the potential prior art activity surrounds a product's prior use or sale, public disclosure occurs when:

• That use or sale involved people free at law and equity to use the product.
• Information can be freely gleaned from the product. (Wenzel, at paras 20-21, 28, 59, 69, 75, 132-139.)

However, public use of a product is not considered to be "publicly available," and the activity in question will not be considered in either an anticipation or obviousness inquiry, when it can be proven that the public use was of an experimental nature (Bayer Inc. v Apotex Inc., 2014 FC 436 at paras 119-120; Bombardier v Arctic Cat, 2017 FC 207, rev'd in part on other grounds 2018 FCA 172 at paras 491­492 (Bombardier); Conway v Ottawa Electric Railway (1904), 8 Ex CR 432 (Can Ex C), at 442; Martin v Ford Motor Co of Canada Ltd, [1967] 2 Ex CR 279 (Can Ex Ct) at para 49).

To assess whether a use of a product was experimental, courts examine whether the user of the product believed their use was experimental, not whether the product owner considered the use experimental (Wenzel Downhole Tools Ltd v National-Oilwell Canada Ltd, 2011 FC 1323 at paras 90 and 141, aff'd on this point 2012 FCA 333 at para 23; Packers Plus Energy Services Inc. v Essential Energy Services Ltd, 2017 FC 1111 at paras 110-123).

Despite these exceptions, a prior art activity based on an invention's publicly available prior use or sale may constitute an anticipatory disclosure if the disclosure of the claimed invention occurred as a result of its use or sale. The courts have provided numerous observations to assist in determining whether a prior use or sale can constitute an anticipatory disclosure, including:

• Sale to the public or use by the public alone is insufficient to prove anticipation. Disclosure of the invention is required.
• For a prior sale or use to anticipate an invention, it must provide an "enabling disclosure."

For a prior sale or use to constitute an enabling disclosure to the public, the invention must be discoverable through analysis or reverse engineering. If reverse engineering or analysis is required, that process must be completed without inventive skill and is limited to the analytical techniques and processes known at the time. It is not necessary to demonstrate this reverse engineering or analysis was actually completed. In addition, the product subject to the analysis need not be exactly replicable. Instead, the question is whether the subject matter of the claims can be ascertained through the analysis. This includes a single embodiment of the claims. (See Wenzel, at paras 132-139.)

Ultimately, any publicly available oral communications, uses, or sales of a product will make that product part of the state of the art only so far as that oral communication, use, or sale makes available the information necessary to disclose and enable the claimed invention (Wenzel at para 134). The degree to which information necessary to disclose the claimed invention became available to the public can turn on the facts of a particular situation and may indeed depend on the extent to which a product became available to the public to view and interact with. For example, a product displayed in such a way that the public can only view the product from afar may result in limited information about the product being made publicly available, while a product the public can interact with may result in more information being made publicly available (see for example Wenzel, at paras 74-75).

Novelty and the Anticipation Test

Claimed Invention

In Canada, it is the claim, or claims, of a patent that determine the scope of the patent's monopoly, the fences that stake out the patentee's property (Free World Trust v Électro Santé Inc., 2000 SCC 66 at paras 14, 31, and 35 (Free World Trust)).

The scope of the claim(s) is in turn determined by construing the claims, a process known as claim construction. Only one construction is completed for each claim in a patent. That one construction is then equally applied to any infringement or validity analyses concerning that claim. This includes the analyses into both novelty (that is, whether the claimed invention is anticipated) and obviousness (that is, whether the claimed invention is inventive) (Free World Trust, at para 31). The process of construing the claims is therefore antecedent to and occurs before any analysis into either infringement or validity (Whirlpool Corp. v Camco Inc., 2000 SCC 67 at para 43 (Whirlpool)).

Claims in Canada are construed in an informed and purposive manner as of the date the patent application was published or laid open to public inspection (Free World Trust, at para 31). They are not construed "in an overly technical or literal way" (Whirlpool, at para 48; Free World Trust, at paras 28-67; Bombardier at paras 293, ­294, 299). Nor can the scope of the claim be expanded based on "vague notions" like the "spirit of the invention" (Whirlpool, at paras 42-50; Free World Trust, at para 31). Purposive construction aims to distinguish between the essential and non-essential elements of each claim.

To be construed in an informed way, a claim must be constructed in light of the common general knowledge shared by the person skilled in the art (PSA) (Free World Trust, at para 44; Pharmascience Inc. v Teva Canada Innovation, 2022 FCA 2 at paras 5-6). The Supreme Court of Canada has described the PSA as a "hypothetical person possessing the ordinary skill and knowledge of the particular art to which the invention relates" (Free World Trust, at para 44) (see Level of Ordinary Skill). When constructing claims, the PSA is assumed to read the patent and its claims with "a mind willing to understand [the] specification that is addressed to [them]" (Free World Trust, at para 44), rather than "a mind desirous of misunderstanding" (Whirlpool, at para 49).

To be construed in a purposive way, the language of the claim(s) must be analyzed through the lens of the PSA both to:

• Give the words and phrases of the claim meaning.
• Distinguish between the essential and non-essential elements of the claimed invention.

(Free World Trust, at para 31.)

This requires analyzing the words of the claim(s) in the context of the patent specification as a whole (Biogen Canada Inc. v Pharmascience Inc., 2022 FCA 143 at paras 71-73 (Biogen); Monsanto Canada Inc. v Schmeiser, 2004 SCC 34 at para 18 (Schmeiser)). The patent's disclosure is therefore always considered when construing a claim (Biogen, at para 71). Despite this, care must be taken to avoid using information obtained from outside of the claim language itself to either expand or narrow the scope of the claims (Free World Trust, at para 51).

Besides the patent specification, and common general knowledge of the PSA, few other pieces of extrinsic evidence can be admitted to aid in the claim construction exercise. Evidence such as inventors' notebooks, prior art, or contemporary documents are generally not admissible for construing the claims (Schmeiser, at para 18; Whirlpool, at para 49). A statutory exception to this prohibition exists under the Patent Act. Section 53.1(1) expressly allows for written communications between the patent applicant (patentee) and the Canadian Patent Office to be admitted as evidence to rebut any representation made by the patentee with respect to claims construction (section 53.1(1), Patent Act; Western Oilfield Equipment Rentals Ltd v M-I LLC, 2021 FCA 24 at para 19; Bauer Hockey Ltd v Sport Maska Inc. (CCM Hockey), 2021 FCA 166 at para 33).

When assessing the essential elements of a claim, there is a presumption that all elements specified in a claim are essential (Allergan Inc. v Sandoz Canada Inc., 2020 FC 1189 at para 46). That presumption can be overturned depending on the answers to questions such as the inventor's intention, as seen in the patent specification, in identifying a claim element as essential or non-essential as well as the PSA's understanding of the invention and how it worked (Whirlpool, at para 45; Free World Trust, at para 55). The Canadian Patent Office has similarly described non-essential elements of a claim as those that are superfluous to the proposed solution the patent gives to a disclosed problem (Manual of Patent Office Practice, at s 12.02.02e, "Determine which elements of the claim solve the identified problem" (MOPOP)).

Once the claims are construed in a purposive and informed way, the scope of the claim is ascertained and the inquiry into whether the claim is patentable over the prior art can begin.

For more information on claim construction, see Practice Note, Patent Scope of Protection: Claim Construction.

Anticipation Analysis

A valid patent claim in Canada must not be anticipated. It must recite novel subject-matter.

The doctrine of novelty (that is, whether a claimed invention is anticipated) in Canada is governed by the Patent Act. Section 2 of the Patent Act states that an invention "means any new and useful art, process, machine, manufacture or composition of matter, or any new and useful improvement in any art, process, machine, manufacture or composition of matter" (emphasis added).

The specific requirements to establish that a claimed invention is new, or novel, is governed by subsection 28.2(1) of the Patent Act, which specifies that the subject matter of a claim must not have been previously disclosed before the prior art's applicable disclosure deadline. If the subject matter of the claim has been previously disclosed before the applicable disclosure deadline, that claim is anticipated and therefore invalid.

The disclosure deadline applicable to an anticipation analysis varies depending on the type of disclosure in issue since Canada is not a complete absolute novelty jurisdiction (see Dates for Prior Art Determinations).

Anticipation in Canada is difficult to prove. To render a patent non-novel the anticipatory disclosure needs to, through the eyes of the PSA, be provided in a single prior art reference or activity and can only be supplemented by the PSA's common general knowledge (Apotex Inc. v Sanofi-Synthelabo Canada Inc., 2008 SCC 61 para 37 (Apotex v Sanofi); Aux Sable Liquid Products LP v JL Energy Transportation Inc., 2019 FC 581 para 114 (Aux Sable); Hoffmann-La Roche Limited v Sandoz Canada Inc., 2021 FC 384 at para 146).

The Supreme Court of Canada decision of Apotex v Sanofi established Canada's approach to the test for anticipation, with reference to UK jurisprudence. To be anticipatory, a single prior art reference or activity needs to both:

• Disclose the claimed subject matter (see Disclosure Requirement).
• Enable the claimed subject matter (see Enabling Disclosure).

(Apotex v Sanofi, at paras 24-30; Aux Sable, at para 90.)

This test:

• Applies equally to all types of patents (Apotex Inc. v Shire LLC, 2021 FCA 52 at para 32 (Shire))
• Is the same regardless of the field(s) (whether the same or different) of endeavor of the patent and prior art involved in the analysis.

Disclosure Requirement

To meet the disclosure requirement, a single prior art reference or activity must disclose the essential elements of a claim (Hospira Healthcare Corporation v Kennedy Trust for Rheumatology Research, 2020 FCA 30 at para 71 (Hospira); Shire at para 36). This does not require the prior art to include "an 'exact description' of the claimed invention" (Abbott Laboratories v Canada (Minister of Health), 2008 FC 1359 at paras 74-75 (Abbott)). Instead, to disclose the essential elements of a claim, the prior art must, if performed, necessarily result in the infringement of all the essential elements of the patent claim (Apotex v Sanofi, at paras 25-28; Shire, at paras 37-38 and 40; Hospira, at para 66).

In accordance with this test, the Canadian Patent Office has acknowledged that the potential prior art need not explicitly disclose all the essential elements of a claim. Inherent disclosure is also possible. This occurs when old and known subject matter is not rendered novel simply by disclosing and claiming a feature which is inherently found (necessarily present) in the prior art (MOPOP at s 18.01.04, "Implicit or Inherent Disclosure"). Provided the disclosure, when performed, would necessarily result in the infringement of the patent claim, that claim is anticipated (Shire, at para 37). This may be done without a person even recognizing what is present or what is happening (Abbott, at paras 74-75).

Similarly, a generic disclosure that discloses a genus will not anticipate a later selection, or specific, claim unless the performance of that generic disclosure would necessarily result in the infringement of the specific claim at issue (see for example Shire, at paras 45-46). One example of this is where the generic, or genus, disclosure includes an illustrative example that is the subject of the later specific, or selection, claim (Swist v MEG Energy Corp., 2021 FC 10 starting at para 140, aff'd 2022 FCA 118). By contrast, a specific, or selection, disclosure will anticipate a later more general claim if performing the specific disclosure would necessarily infringe the later general claim (see for example Valence Technology Inc v Phostech Lithium Inc., 2011 FC 174 at paras 228-230, aff'd 2011 FCA 237; Aux Sable, at para 98).

Enabling Disclosure

To meet the enablement requirement, the "reference in the prior art must be sufficiently detailed as to enable a PSA to perform the claimed invention without the exercise of inventive ingenuity or undue experimentation" or burden (Shire, at para 39; Apotex v Sanofi, at para 37). When doing so, the PSA may rely on their common general knowledge. Obvious errors or omissions in the prior art reference will not prevent enablement as long as reasonable skill and knowledge in the art could readily correct the error or find what was omitted (Apotex v Sanofi, at para 37).

To determine whether the claimed invention can be performed without undue burden, the nature of the invention must also be considered.

For example, if the invention takes place in a field of technology in which trials and experiments are generally carried out, the threshold for undue burden will tend to be higher than in circumstances in which less effort is normal.

(Apotex v Sanofi, at subpara 37(3).)

Routine trials are generally not considered undue. Despite this, prolonged and/or arduous experimentation or trial and error would be considered an undue burden. (Sanofi v Apotex, at subpara 37(3)).

Obviousness Analysis

Level of Ordinary Skill in the Art

The PSA and their common general knowledge are relevant to both construe the claims of a patent document and determine whether a prior disclosure is anticipatory of the patent document's claims. Identifying the PSA and their common general knowledge is also relevant to determining whether the claims are non-obvious above the prior art (Apotex v Sanofi, at para 67).

The PSA is a notional worker, or workers in a team, who has an ordinary level of competence, skill, and knowledge incidental to the field or trade to which the patent document relates and a mind willing to understand the specification.

When identifying the PSA, the court must take a fair and generous view as to the sort of person (or team) the PSA is. They are neither the most exceptional and skilled nor are they the least qualified or slowest witted (Janssen-Ortho Inc. et al. v Novopharm Limited, 2006 FC 1234 at para 90 (Janssen-Ortho Inc.), aff'd 2007 FCA 217 (Janssen-Ortho Inc FCA); Allergan Inc v Sandoz Canada Inc, 2020 FC 1189 at para 57 (Allergan)).

Although a PSA is deemed to be reasonably diligent at keeping up with advances in their field, they are "unimaginative and uninventive" (Valeant Canada LP/ Valeant Canada SEC v Generic Partners Canada Inc., 2019 FC 253 at para 44). Importantly, the PSA must be sufficiently versed in the art to which the patent relates so that they are capable, on a technical level, to appreciate and understand the nature and description of the invention, including the entirety of the patent (Whirlpool, at para 53; Janssen Inc v Teva Canada Ltd, 2020 FC 593 at para 98; Janssen Inc. v Teva Canada Ltd, 2015 FC 184 at para 40; Allergan, at para 56; Angelcare Canada Inc et al v Munchkin, Inc et al, 2022 FC 507 at para 80). The level of knowledge of the PSA will therefore vary based on the subject matter of the patent. For example, "[r]ocket science patents may only be comprehensible to rocket scientists" (Whirlpool, at para 71; Janssen-Ortho Inc., at para 90).

The common general knowledge of the PSA does not include all information available in the public domain, or even the information available to the inventor(s) (Whirlpool, at paras 70-71; Pfizer Canada Inc. v. Canada (Minister of Health), 2005 FC 1725 at paras 262-264). Instead, it only includes the information generally known at the relevant time (that is, the claim date) by PSAs in the field (or fields) to which the patent relates (Apotex v Sanofi, at para 37; Western Oilfield Equipment Rentals Ltd et al v. M-I LLC, 2021 FCA 24 at para 190 (Western Oilfield Equipment Rentals Ltd)). This includes information that the PSA may reasonably be expected to know or is able to find out (Janssen-Ortho Inc FCA, at subpara 25(3)). While it is therefore possible for the common general knowledge of the PSA to include some patents or prior art, it does not include all patents or all prior art disclosed to the public (Eurocopter c Bell Helicopter Textron Canada Ltée, 2013 FCA 219 at para 64 (Eurocopter); Janssen-Ortho Inc. FCA, at subpara 25(3)).

The source of information that is contained in the common general knowledge of the PSA need not be in a published format. Information that is otherwise passed among people in the field, for example through discussions, can also form part of the common general knowledge of the PSA (Janssen-Ortho Inc FCA, at subpara 25(3)).

Finally, the common general knowledge of the PSA not only includes the information the PSA would be expected to know, but also their attitudes, trends, and expectations (Janssen-Ortho Inc FCA, at subpara 25(4)).

Obviousness Analysis

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 relates (section 28.3, Patent Act).

Similar to the provisions of the Patent Act governing the test for anticipation (see Dates for Prior Art Determinations and Determining Whether a Claimed Invention is Anticipated), in an obviousness inquiry the disclosure deadlines applicable to the prior art vary depending on the type of disclosure(s) in issue.

Obviousness in Canada is assessed on a claim-by-claim basis (Astrazeneca Canada Inc. v Apotex Inc., 2017 SCC 36 at para 54; Shire, at paras 26-27; Hospira, at para 71). A patent claim is invalid for obviousness if, based on the information that was available to the public before the applicable disclosure deadline(s), the subject matter of that claim would have been obvious to the PSA. There is no concept of prima facie obviousness in Canada, unlike in the United States.

To assess whether a specific claim would have been obvious to the PSA, each claim is evaluated against what is known as the Sanofi test (from the Supreme Court of Canada decision of Apotex v Sanofi). Although articulated by the Supreme Court of Canada, the Sanofi test is itself based on the approach taken by the UK Court of Appeal in Windsurfing International Inc. v. Tabur Marine (Great Britain) Ltd., [1985] R.P.C. 59 (C.A.) and later refined in Pozzoli SPA v. BDMO SA, [2007] EWCA Civ 588. The four steps of the Sanofi test are:

• Identify the notional PSA and the relevant common general knowledge of that person (see PSA and Common General Knowledge).
• Identify the inventive concept of the claim in question or if that cannot readily be done, construe it (see Identity of the Inventive Concept).
• 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 (see Differences Between Inventive Concept and the State of the Art).
• Viewed without any knowledge of the alleged invention as claimed, determine whether those differences constitute steps which would have been obvious to the person skilled in the art or whether they require any degree of invention (see Inventiveness Determination).

(Apotex v Sanofi, at para 67.)

For more information on inventive step in the UK, see Practice Note, Patentability: Inventive Step: UK Four-Step Approach to Assessing Obviousness.

PSA and Common General Knowledge

From a practical perspective, the first stage of the Sanofi test is usually completed prior to claims construction. As noted above:

• The PSA is a notional worker that has an ordinary level of competence, skill, and knowledge incidental to the field or trade to which the patent relates and a mind willing to understand the specification.
• The common general knowledge of the PSA includes all information that the notional worker would be expected to know.

(See Level of Ordinary Skill in the Art.)

Identity of the Inventive Concept

At the second stage of the Sanofi test, the inventive concept of the claim is determined in order to ascertain what, if anything, makes the construed claim inventive (Shire at para 76). There is no statutory definition of the term "inventive concept," and the term does not appear in the Patent Act. However, the Federal Court of Appeal has in the past specified that the term inventive concept is not materially different from the idea of the "solution taught by the patent" (Shire, at paras 76 and 78; Bristol-Myers Squibb Canada Co v Teva Canada Ltd, 2017 FCA 76 at para 74).

At times, identification of the inventive concept of a claim may be "readily apparent." This is particularly the case where the parties agree on it. Where identification of an inventive concept is not "readily apparent," the inventive concept of each claim must be construed (Shire, at para 67). Although similar to the claim construction exercise, construing the inventive concept is its own discreet inquiry (Shire, at paras 68 and 75; Mylan Pharmaceuticals ULC v Eli Lilly Canada Inc., 2016 FCA 119 at paras 40-41 ("Mylan")).

Construing the inventive concept involves first an examination of the previously completed claims construction exercise to determine if the inventive concept can be determined from that alone. If the inventive concept is not apparent after the examination of the construed claims, recourse to the specification is allowed to determine if the specification provides any insight or clarification into the inventive concept of that claim (Shire, at para 67). The ability to consider the specification to aid in construing the inventive concept of a claim is particularly important in the case of bare chemical formula claims because what makes the chemical inventive is not necessarily its chemical structure but its inherent properties (Shire, at paras 72-73 and 76).

However, similar to claim construction, when recourse to the specification is required to construe the inventive concept of a claim, care must be taken to avoid using the specification to construe the inventive concept of the claim more narrowly or widely than the text will allow (Shire, at para 67). For example, it may generally be improper to read into an independent claim a limitation explicitly stated to be optional in the specification and further included in a dependent claim (Shire, at paras 92-94; Tetra Tech EBA Inc. v Georgetown Rail Equipment Company, 2019 FCA 203 at paras 113-115).

Note that while obviousness is determined on a claim-by-claim basis, and each claim will have its own inventive concept:

• One inventive concept will flow through all the claims of a patent.
• Overlap between each claim's inventive concept is expected.

(Shire, at paras 77, 87-88; Pharmascience Inc. v Bristol-Myers Squibb Canada Co., 2022 FCA 142 at paras 57-59.)

Provided the inventive concept that flows through all the claims is determined to be non-obvious, further explicit consideration of the inventive concepts of the other claims is not typically necessary (Shire, at para 87). However, where the inventive concept that flows through the claims is determined to be obvious, each claim should be separately reviewed to determine if the inventive concept of each claim is non-obvious.

Differences Between Inventive Concept and the State of the Art

At the third stage of the Sanofi test, the differences between the inventive concept and the matter which forms the state of the art are compared. In Canada, it is possible to combine multiple references and activities to form the basis of an obviousness objection. Indeed, all public disclosures whose applicable disclosure deadlines have passed are considered prior art and can become part of the "mosaic" that forms the state of the art. This includes potential prior art that:

• Is in other languages.
• Is from other technological fields (or non-analogous art).
• Would be difficult to find.

(Hospira, at para 86; Allergan Inc v Apotex Inc, 2022 FC 260 at paras 630-634 (Allergan v Apotex)).

The "mosaic" of the prior art is then compared to the inventive concept of the claim to determine the differences between the two. However, even in instances where the "mosaic" encompasses all aspects of the inventive concept, a court or examiner must still proceed to the fourth stage of the analysis. At that time, the question becomes whether, given the obscure nature of one or more of the pieces of prior art, would the PSA have thought to combine the prior art to arrive at the invention (Google LLC v Sonos, Inc, 2022 FC 1116 at paras 96-98).

Inventiveness Determination

At the fourth stage of the Sanofi test, it must be determined whether the differences between the state of the art and the inventive concept of the claim are either obvious or the result of inventive ingenuity. In other words, would the PSA come directly and without difficulty to the particular combination of elements of the invention (Bridgeview Manufacturing Inc. v 931409 Alberta Ltd (Central Alberta Hay Centre), 2010 FCA 188 at para 52 (Bridgeview)). As phrased by the Canadian Patent Office, the question is "[d]o the differences constitute an inventive step?" (MOPOP at s 18.02.02e "Do the differences constitute an inventive step? (Step 4)").

This inquiry is conducted through the lens of the PSA:

• With their common general knowledge and views of the state of the art.
• Without any knowledge of the alleged invention as claimed.

(Apotex v Sanofi, at para 67.)

When viewing the state of the art, care must be taken to avoid hindsight bias (Bridgeview, at paras 50 and 51; Tensar Technologies, Limited v Enviro-Pro Geosynthetics Ltd, 2019 FC 277 at para 128 (Tensar)).

The question at stage four of the Sanofi test must be assessed objectively and purposively, having regard to the problem addressed by the patent (Shire, at para 103). However, at this stage of the inquiry there is no one test to apply, as the circumstances of each case may vary (MOPOP at s 18.02.02; Apotex v Sanofi, at paras 61-64; Janssen-Ortho Inc FCA, at para 25). For example, inventive ingenuity may be found in:

• Coming up with the underlying idea or problem to be solved.
• Putting the idea into practice.
• The combination of known parts. In this case, the question becomes whether the combination of the disclosures to form the "mosaic" was obvious.

(Allergan v Apotex, at para 556; Bridgeview, at para 51.)

Therefore, the question at stage four is answered in view of:

• The specific facts of the case.
• Any expert opinion presented.
• Any other factors that are presented for consideration.

Both examiners at the Canadian Patent Office and the court may consider factors such as:

• The climate in the relevant field at the time the claimed invention was made, including not only knowledge and information available but also attitudes, trends, prejudices, and expectations that would define the PSA.
• Any motivation in existence at the time of the claimed invention to solve a recognized problem in the field of the invention.
• The time and effort involved in creating the claimed invention.
• The likelihood that a PSA would have found the various disclosures.
• Whether there were other possible pathways to the claimed solution in the state of the art that pointed away from the solution of the claimed invention.
• Any motivation there may have been to combine the various disclosures. Motivation is relevant in determining whether the skilled person has a good reason to pursue "predictable" solutions. The degree of motivation cannot transform a possible solution into an obvious one.
• The likelihood that the PSA would have actually combined the various disclosures. Where the disclosures in question lie outside the field of claimed invention, there may be less of a likelihood that the PSA would have combined them.

(MOPOP at s 18.02.02e "Do the differences constitute an inventive step? (Step 4)"; Janssen-Ortho Inc, at para 113, aff'd Janssen-Ortho Inc FCA, at para 25; Sanofi-Aventis Canada Inc v Ratiopharm Inc., 2010 FC 230 at paras 83-87; Hospira, at para 86; Tensar, at para 154; Pfizer Canada Inc. v Apotex Inc., 2009 FCA 8 at paras 42-45.)

Additionally, if an invention relates to an area "of endeavour where advances are often won by experimentation," courts and examiners may consider it appropriate to use an "obvious to try" test, that is, whether the claimed invention was obvious because it was more or less self-evident to try to obtain the claimed invention (Apotex v Sanofi, at paras 66 and 68; Wenzel, at paras 91 to 108, especially para 95). When considering whether the claimed invention would have been obvious to try, the following factors may be considered:

• Is it more or less self-evident that what is being tried ought to work? Are there a finite number of identified predictable solutions known to persons skilled in the art?
• What is the extent, nature, and amount of effort required to achieve the invention? Are routine trials carried out or is the experimentation prolonged and arduous, such that the trials would not be considered routine?
• Is there a motive provided in the prior art to find the solution the patent addresses?

(Apotex v Sanofi, at para 69; Hospira, at paras 89-90.)

The actual history of the claimed invention, and the inventor's conduct that ultimately led to it, may also be relevant to the obvious-to-try inquiry (Apotex v Sanofi, at para 70). For example, whether:

• The claimed invention was reached quickly, easily, or inexpensively.
• Other approaches were explored before the one that resulted in the claimed invention.

While these more contextual factors may not be, on their own, determinative, they can be considered and weighed before concluding whether the claimed invention was obvious (Shire, at para 107; MOPOP at s 18.02 "Obviousness – June 2016" and 18.02.02e "Do the differences constitute an inventive step? (Step 4)").

In addition to the above factors, other, secondary, factors may also be considered in the fourth stage of the Sanofi test.

Secondary Considerations

The inquiry into whether a claim was obvious in light of the prior art in Canada is not intended to be rigid. Courts and examiners are to take an "expansive and flexible approach," and the obviousness analysis at the fourth stage of the Sanofi test can include an examination of "any secondary considerations that [will] prove instructive" to the analysis (Apotex Inc. v Pfizer Canada Inc., 2019 FCA 16 at para 32; Apotex v Sanofi, at para 63).

While these secondary considerations are not necessarily determinative on their own, they can include:

• The conduct of other industry participants, including any failed attempts made by others.
• The presence, or lack, of any industry motivation or long-felt need.
• Conventional wisdom at the time the claimed invention was created.
• The commercial success of the claimed invention.
• The novelty or superiority of the claimed invention over what was previously available.
• The reaction of the community after the publication of the claimed invention.
• Any meritorious awards received for the claimed invention.
• The degree of use of the claimed invention.
• Whether the claimed invention was preferred over its alternatives.
• The degree of imitation of the claimed invention since its introduction.

(Bauer Hockey Ltd v Sport Maska Inc. (CCM Hockey) , 2020 FC 624 at paras 145–151, aff'd 2021 FCA 166; Apotex v Sanofi, at para 63; Wessel v Energy Rentals Inc, 2004 FC 791 at para 91; Apotex v Sanofi, at paras 70-71; Guest Tek Interactive Entertainment Ltd v Nomadix, Inc., 2021 FC 276 at para 69; Pfizer Canada Inc. v Apotex Inc., 2009 FCA 8 at para 31; Janssen-Ortho Inc FCA, at para 25)

In particular, the commercial success of the claimed invention is a factor relevant to an analysis of obviousness as "commercial success may reflect the fact that many persons were motivated to fill the commercial market, which in turn may suggest inventive ingenuity" (Tearlab Corporation v I-MED Pharma Inc., 2019 FCA 179 at para 68). Similarly, "the mere fact that [a] competitor took steps to copy the [invention] is indicative of [its] inventiveness." Beyond the behavior of competitors, the reaction of the community may also give clues as to the invention's inventiveness, for example, "[w]as there amazement expressed by the community at its first publication?" (Bombardier, at subpara 91(2).)

To argue one or more of these secondary considerations, an applicant or patent owner must provide evidence to support its position. When considering certain secondary considerations such as the commercial success of the invention, the evidence of commercial success should relate to the invention and its inventive concept (Pollard Banknote Ltd v BABN Technologies Corp, 2016 FC 883 at para 227). Commercial success attributable to advantages that are not claimed in the patent cannot be relied upon to prove non-obviousness (Kramer v Lindsay Specialty Products Ltd, 8 CIPR 84 (Fed TD), 1986 CarswellNat 603 at paras 41-43).

Although the evidence available may vary depending on the situation, the evidence submitted can include:

• Financial or sales information.
• Evidence of awards or reviews.
• Evidence of competitor action.

The strength of the evidence is assessed on a case-by-case basis as to its appropriate weight in determining whether the claimed invention was obvious.

However, unlike in a full proceeding before a Canadian court, the Canadian Patent Office does not have the ability to implement confidentiality orders to protect sensitive commercial information from becoming public knowledge. As such, care must be taken when filing evidence in the original prosecution of a patent application where the evidence may be of a commercially sensitive nature.

Practical Considerations

Practically, from a technical or scientific perspective, considerations of prior art are not often substantially different between Canada and the United States. When beginning a search to identify potential prior art, it is therefore recommended to use a good commercial search tool to look for prior art around the world. The advantage to these commercial search tools over free search tools is their enhanced power and searching capabilities.

In addition to searching for prior art using key words, it is also recommended to search for the patent holdings and other publications of key competitors in a given area. As some publications, patents, and patent applications use different key words to identify the same things, searching in this way allows for potentially broader and more thorough results.

Once potential patent documents of interest have been identified, watches can be placed on them to see how they progress through their various patent offices.

If an examiner does issue an objection for a Canadian patent application based on the prior art, it is important to consider whether the examiner used the current applicable legal standards in making their assessment. In the context of an obviousness objection, although many examiners complete their assessment intuitively and automatically, an applicant can nevertheless challenge the basis of that objection by arguing the examiner did not properly follow and apply the four-step Sanofi test. Applicants may also wish to consider whether to amend the claims to assist in overcoming the cited prior art.

When considering whether to challenge the validity of an issued Canadian patent, note that Canada does not allow for an opposition procedure like the one that exists in the United States and or other countries. Instead, patent validity can be challenged through the courts. However, when drafting pleadings for the court, all prior art intended to be relied upon must be expressly included and pleaded. If new prior art is later discovered, the pleadings must be amended to add it.