Introduction
Illustrative claim set
Multiply-dependent claims
Amendments to the Canadian Patent Rules introducing excess claim fees will come into force soon and will apply to any application in which examination has not been requested before 3 October 2022 (for further details, see "New rules: request examination of Canadian patent applications before 3 October 2022").
This article is part of a series of articles discussing options and best practices for minimising claim fees under the new rules.(1) There are three possible approaches for minimising the number of claims and associated excess claim fees:
- cancelling claims;
- making use of multiply-dependent claims; and
- consolidating the subject matter of separate claims as alternatives within a single claim.
This article focuses on multiply-dependent claims.
The following illustrative claim set will be used throughout the remainder of this article to illustrate claim fee calculations and matters of claim interpretation and validity:
- claim one – a pharmaceutical composition comprising compound A and a pharmaceutically acceptable excipient;
- claim two – a pharmaceutical composition comprising compound B and a pharmaceutically acceptable excipient;
- claim three – a pharmaceutical composition comprising compound C and a pharmaceutically acceptable excipient;
- claim four – the pharmaceutical composition according to any one of claims one to three, in the form of a tablet;
- claim five – the pharmaceutical composition according to any one of claims one to three, in the form of a capsule;
- claim six – the pharmaceutical composition according to any one of claims one to five, wherein said pharmaceutically acceptable excipient comprises:
- a flavouring agent;
- a disintegrant;
- a colourant;
- a glidant; or
- a preservative;
- claim seven – the pharmaceutical composition according to any one of claims one to six, comprising, as a non-nutritive sweetener, a sugar alcohol selected from the group consisting of:
- xylitol;
- maltitol;
- sorbitol;
- mannitol; and
- erythritol; and
- butylated hydroxyanisole;
- butylated hydroxytoluene;
- sodium metabisulfite; or
- propyl gallate.
- claim eight – the pharmaceutical composition according to any one of claims one to seven, comprising, as a preservative, an antioxidant that is:
Multiply-dependent claims (claims four to eight in the illustrative claim set) are permitted, and a multiply-dependent claim may depend on another multiply-dependent claim (claims six to eight in the illustrative claim set). In contrast to US practice, in Canada, a multiply-dependent claim counts only as a single claim for the purposes of calculating claim fees, the relevant provisions of the rules providing:
A claim that defines the subject-matter of an invention in the alternative, including a dependent claim within the meaning of section 63 that refers to more than one preceding claim, counts as a single claim for the purposes of [claim fee calculations].(2)
The illustrative claim set, therefore, contains only eight claims for fee calculation purposes. Claim fees would accrue quickly if the multiply-dependent claims were rewritten with only single dependencies. For instance:
- each of claims four and five could be written as three singly-dependent claims;
- claim six could be written as nine singly-dependent claims;
- claim seven could be written as 18 singly-dependent claims; and
- claim eight could be written as 36 singly-dependent claims.
Thus, to obtain the same coverage without the use of multiple claim dependencies, the illustrative claim set would have to contain 72 rather than eight claims for fee calculation purposes.
Pursuant to section 58 of the Patent Act, invalid claims in a patent do not affect valid claims:
When, in any action or proceeding respecting a patent that contains two or more claims, one or more of those claims is or are held to be valid but another or others is or are held to be invalid or void, effect shall be given to the patent as if it contained only the valid claim or claims.
In contrast to the new fee calculation provisions, the Patent Rules describe each claim dependency within a multiply-dependent claim as a separate claim.
Subsection 63(3) of the Patent Rules provides that: "A dependent claim that refers to more than one claim must refer to those claims in the alternative only."
Subsection 63(4) of the Patent Rules provides that:
A dependent claim is considered to include all the limitations contained in the claim to which it refers or, if the dependent claim refers to more than one claim, any particular alternative of the dependent claim is considered to include all the limitations contained in the particular claim in respect of which it is considered.
Moreover, in Consolboard,(3) without referencing any particular provision of the Patent Act or Patent Rules,(4) the Supreme Court of Canada held that dependent claim 10 of Canadian Patent No. 565,618 directed to "[a] consolidated structure as claimed in claim 7, 8 or 9, in which the tapered ends of the wafers are ragged", was valid "in so far as claim 10 includes claim 7". Each of claims seven, eight and nine were independent claims to a "consolidated structure" – namely, a wafer board composed of woody wafers and a thermosetting resinous binder. Independent claim seven was found to be valid but claims eight and nine invalid. Multiply-dependent claim 10 was valid when dependent on claim seven. The Consolboard approach, as it applies to multiply-dependent claims, was followed by the Federal Court in GD Searle.(5) Multiply-dependent claims have thus been found to constitute separate claims for the assessment of validity.
There are other dependent claim formats that might be employed to reduce claim fees and that have not been specifically considered by the courts or that are simply uncommon.
A claim in the form "16. A compound according to any one of claims 1-5, a pharmaceutical composition according to any one of claims 6-10, or a kit according to any one of claims 11-15, wherein R1 is -OH" has not routinely been used in Canada but could in principle be employed to minimise claim fees. Even though the preamble of the claim refers to preceding claims in different categories, reference is made to each claim separately and the claim meets all the formal requirements for a dependent claim set out in section 63 of the Patent Rules. Consistent with the finding of the Supreme Court in Consolboard, it appears claim 16 should be considered separately with respect to each of its dependencies. For instance, if claim five to a compound were invalid but claim 12 to a kit valid, claim 16 could be valid in so far as it depends from, and further limits, claim 12 directed to a kit.
A commonly used claim format is "17. Use of a compound according to any one of claims 1-5 for the treatment of diabetes".
This claim differs from previous examples in that the claim is directed to use and refers to preceding claims directed to compounds. The claims are thus in different "categories", in contrast to the claims in the illustrative claim set above.
Referencing somewhat different examples, the Manual of Patent Office Practice (MOPOP) states that claims of one category referring to claims of another category may be permitted, but are not dependent claims:(6)
Claims are also permitted to refer to other claims or parts of claims of the same or of another category, in order to avoid repeating lengthy definitions already given and to simplify claiming, provided they do not become ambiguous as a result of such dependency, thereby contravening section 27(4) of the Patent Act. Such claims however are not dependent claims and section 63 of the Patent Rules does not apply. The patentability of the claim referred to does not necessarily imply the patentability of the dependent claim containing the reference. (Emphasis added.)
However, the MOPOP is not a binding legal authority, and no authority is cited for this proposition. Indeed, exemplary claim 17 appears to meet all the requirements of a dependent claim set forth in subsections 63(1)-(3) of the Patent Rules:
- It "includes all the features of one or more other claims" in that it does not cover the use of any compounds not encompassed by the compound claims to which it refers.
- It refers "by number" to the other claim or claims.
- It states "the additional features claimed". In this regard, the additional feature is the limitation to the use of the compound for treating diabetes. The preceding claims are infringed by the use of the compound for any purpose, whereas claim 17 is limited in scope to use in the treatment of diabetes.
- It refers only to "a preceding claim or claims".
- It refers to claims 1-5 "in the alternative only".
As it seems to meet the prescribed formal requirements, it appears that exemplary claim 17 reasonably should be construed as a dependent claim pursuant to subsection 63(4) of the Patent Rules and therefore be:
considered to include all the limitations contained in the claim to which it refers or, if the dependent claim refers to more than one claim, any particular alternative of the dependent claim is considered to include all the limitations contained in the particular claim in respect of which it is considered.
Nevertheless, for the avoidance of any doubt, the most cautious course is to include a separate claim for subject-matter of particular importance, even if excess claim fees may be incurred.
For further information on this topic please contact David Schwartz at Smart & Biggar by telephone (+1 613 232 2486) or email ([email protected]). The Smart & Biggar website can be accessed at www.smartbiggar.ca.
Endnotes
(1) For the first article in the series, see "Canada's new patent claim fee rules: alternative embodiments within a single claim – part one".
(2) This language is found in both subsection 80(1.1) (excess claim fees when requesting examination) and subsection 87(1.1) (excess claim fees payable with final fee) of the Patent Rules.
(3) Consolboard Inc v MacMillan Bloedel (Sask) Ltd, [1981] 1 SCR 504 at pp 537-538.
(4) Including section 60 of the Patent Act, RSC 1970, chapter P-4, the previous counterpart to current section 58.
(5) GD Searle & Co v Novopharm Limited, 2007 FC 81 (celecoxib) at para [26]-[32].
(6) MOPOP at section 16.06. Notably, the MOPOP is not a binding legal authority. As stated in section 1.01:
This manual is a guide only and should not be considered legally binding. If there are inconsistencies between the information in this manual and the applicable legislation, the legislation must be followed. The information provided is for information purposes only and should not be relied upon for legal purposes or business decisions.