“Consisting essentially of” in Canadian Claim Construction


Due to the flexible nature of the law of claims construction in Canada, the construction of the commonly used transitional phrase, “consisting essentially of,” may surprise those not familiar with Canadian patent practice. As such, when preparing patent applications for filing in Canada, the term should be used with caution.

The use of the phrase “consisting essentially of” in claims is common in other jurisdictions, particularly in the United States. Thus, practitioners often assume that this term has the same meaning in Canada as in the United States. In the United States, the phrase limits the scope of a claim to the specified materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention.1 In Europe, the phrase is held to mean that “specific further components can be present, namely those not materially affecting the essential characteristics” of the specified materials or steps. However, this phrase does not necessarily have a similar meaning in Canada.

In section 11.01 of the Canadian Patent Office Manual of Patent Office Practice; “consisting essentially of” is listed with “consisting of,” which appears to suggest that “consisting essentially of” has the same meaning, or close to the same meaning, as “consisting of,”: a term that is well established to limit the scope of a claim to the specified materials or steps.2 However, the Patent Appeal Board has variously interpreted “consisting essentially of” to mean “comprising,”3,4 to exclude materials or steps not specified in the claim5, or to have a meaning similar to that in the US or Europe.6

Courts in Canada have also flexibly interpreted the term “consisting essentially of”. The Federal Court has rejected the US interpretation.7 In a recent decision, the Federal Court interpreted “consisting essentially of” to exclude materials and steps not specified in the claim.8 In another decision, the Federal Court construed a claim directed to “[a]n abridged … composition” in view of the description, another dependent claim, and “abridged” in the preamble of the claim to determine that “consisting essentially of” included other materials and steps not specified in the claim.9 On the other hand, both decisions state that in line with the Supreme Court of Canada’s decision in Free World Trust,10 the claims should be purposively construed and the whole disclosure must be considered.

Thus, the phrase “consisting essentially of” is not likely to have the established meanings as it does in the United States and Europe. Rather, the term will be interpreted in view of the whole disclosure of the particular specification. English is a widely used and adaptable language but those using it would do well to keep in mind that Canadians, Americans and the English themselves adapt it and interpret it according to their own needs.

Authors: Lei GaoAndrew Kaikai

This article is for information purposes only and does not constitute legal or professional advice.

1 In re Herz, 537 F.2d 549, 551-52, 190 USPQ 461, 463 (CCPA 1976) (emphasis in original), citing In re Janakirama-Rao, 317 F.2d 951 (CCPA 1963).
2 ECLI:EP:BA:2012:T075910.20120322 at page 15 (emphasis in original) (European Boards of Appeal of The European Patent Office 2012).
3 RE APPLICATION FOR PATENT BY GENERAL ELECTRIC CO. (NOW PATENT NO. 1,116,775), 66 C.P.R. (2d) 261 at paras 5, 6 (Patent Appeal Board 1980).
4 Geron Corp., Re, 93 C.P.R. (4th) 384 at paras 33, 37, and 80 (Patent Appeal Board 2011).
5 Union Carbide Chemicals & Plastics Technology LLC, Re, 2010 CarswellNat 5815 at para 24 (Patent Appeal Board 2010).
6 Rhodia Electronics and Catalysis, Re, 2014 CarswellNat 3625, 128 C.P.R. (4th) 237 at para 47 (Patent Appeal Board 2014).
7 Abbott Laboratories v. Canada (Minister of Health), 2006 FC 69 at para 68, aff’d 2007 FCA 83
8 Eli Lilly Canada Inc. v. Mylan Pharmaceuticals ULC, 2015 FC 178 at para 103.
9 Abbott Laboratories, supra at paras 56, 57.
10 Free World Trust c. Électro Santé Inc., 2000 SCC 66