Caution in Following UK Caselaw Regarding Added Matter

Western Oilfield Equipment Rentals Ltd v M-I LLC 2021 FCA 24 Locke JA: Gleason, Mactavish JJA affg 2019 FC 1606 O'Reilly J

            2,664,173 / Shaker and Degasser Combination

Previous posts have provided some background on this case and addressed reasonable compensation, the Gillette defence and the “best mode” requirement. This post turns to Locke JA’s comments regarding added matter.

Section 38.2(2) of the Act provides that an application cannot be amended to add matter “that cannot reasonably be inferred” from the specification as it was on its filing date. This provision broadly corresponds to Art 123(2) of the EPC, which provides that the application or patent may not be amended to add matter “which extends beyond the content of the application as filed.” As previously noted, the claims that were infringed had been introduced during prosecution, after the patentee became aware of the appellants’ product. The appellants argued that these claims were invalid for added matter [138]. There is little Canadian caselaw dealing with our provision, and the appellants had therefore relied on UK caselaw as support for a “strict” test that “subject matter should be considered to have been added unless such matter is clearly and unambiguously disclosed in the original application either explicitly or implicitly” [140]. (See here for my discussion of O’Reilly J’s decision on this point.)

Locke JA remarked that we should be “wary” of following the UK approach, for three reasons. First, “it presumes that matter has been improperly added, and places the burden on the respondent to establish otherwise,” whereas in Canadian law a patent is presumed to be valid (s 43(2)) and accordingly the burden is on the party attacking the patent. Second, the text of the provision is different, and in particular the EPC provision* does not have any kind of “reasonableness” language: [142]. Third, the UK provision provides explicitly for patent revocation, while s 38.2 does not [143]. Accordingly, Locke JA simply applied the statutory “cannot reasonably be inferred” test and held that the feature in question was “at least reasonably inferable” from the original specification [147].

I agree with Locke JA we should not adopt the UK approach uncritically, for all the reasons he gives. On the other hand, comparative law can potentially be very useful, particularly when, as in this case, there little Canadian caselaw and a great deal of UK caselaw; the foreign caselaw can help illustrate the kinds of problems that may arise and that need to be taken into consideration, even if we do not adopt the same solutions as foreign law. For example, the problem of “intermediate generalization” arises when the specification provides a number of specific examples and the patentee seeks to claim a broader class which is said to be exemplified by those examples. This has caused considerable difficulty and has been addressed in a number of EPO Board decisions and UK cases: see eg Nokia v IPCom [2013] RPC 5 [56]ff. While the problem does not arise in this case, the European jurisprudence is likely to be useful in illuminating the issues when it does arise, even if the Canadian courts choose not to adopt the European solution.

In my view, Phelan J struck exactly the right note in Amazon.com 2010 FC 1011 [32] when he observed that it can be useful to look to other regimes when faced with a question that is novel in Canadian law, but this must be done “mindfully” [32].

A “mindful” consideration of foreign law means that we should not simply pluck a test from foreign jurisprudence. It is important to get the foreign law right before we decide whether to adapt it to the Canadian context. In the UK approach, added matter is permisible if it can be “implicitly” inferred from the original specification, and this may soften the apparently strict nature of the test. So, another articulation provided by Jacob LJ in Vector Corp [2007] EWCA Civ 805 [4] is that:

[T]he test of added matter is whether a skilled man would, upon looking at the amended specification, learn anything about the invention which he could not learn from the unamended specification.

Given that a skilled person approaches the specification with “a mind willing to understand,” it may be that the test is not so strict after all. On the one hand this suggests that UK law may provide some helpful guidance despite the differences in the text; but on the other hand, the need to understand the subtleties of foreign law is another reason to be “wary” of it.

Another point is that it may be helpful to look to the purposive considerations adverted to in foreign law. To the extent the purpose of the Canadian and UK provisions are different, that is additional reason to be wary of the same test, but to the extent the purpose is the same, that is a reason to consider the foreign test more closely, always subject to the text of the provision.

This is perhaps most relevant to Locke JA’s third point, that the UK Act provides explicitly for patent revocation while s 38.2 does not [143]. This raises the question of whether added matter contrary to s 38.2 is a basis for invalidating a claim in a granted patent, or whether it is only ground for refusing an amendment during prosecution. Some of the purposive considerations discussed by Jacob LJ in Vector Corp are potentially relevant to this issue:

[5] The reason for the rule was explained by the Enlarged Board of Appeal of the EPO in G1/93 ADVANCED SEMICONDUCTOR PRODUCTS/Limiting feature [1995] EPOR 97 at [Reasons 9]:

"With regard to Article 123(2) EPC, the underlying idea is clearly that an applicant shall not be allowed to improve his position by adding subject-matter not disclosed in the application as filed, which would give him an unwarranted advantage and could be damaging to the legal security of third parties relying upon the content of the original application."

[6] Mr Richard Arnold QC provided a clear articulation as to how the legal security of third parties would be affected if this were not the rule:

The applicant or patentee could gain an unwarranted advantage in two ways if subject-matter could be added: first, he could circumvent the "first-to-file" rule, namely that the first person to apply to patent an invention is entitled to the resulting patent; and secondly, he could gain a different monopoly to that which the originally filed subject-matter justified.

These considerations seems to me to also be relevant in the interpretation of the Canadian provision, always subject to the text.

*Note that the UK courts rely directly on Art 123(2) rather than on the somewhat differently worded s 76(3) of the Patent Act 1977, which was a “cack-handed” implementation of the EPC provision: Napp Pharma [2009] EWCA Civ 252 [69].