Claim construction and infringement

This article is part of the latest edition of our Patents: Review of the Year publication.

Construction

To what extent must a feature relied upon for technical effect or technical contribution be written into the language of the claim? Readers may recall HHJ Hacon’s decision last year in Teva v Novartis⁵, in which Novartis’ patent for a film-coated tablet formulation of deferasirox was lost because the advantageous features of improved bioavailability and reduced food effect were not spelt out in the claims and so were held not to be part of the inventive concept for the purpose of the Pozzoli approach. As such, the claim was held to cover any sort of tablet and was therefore bad for obviousness.

Fast forward 12 months and contrast that with Mellor J’s decision in Astellas v Teva and Sandoz⁶, also a pharmaceutical formulation case concerning the benefit of avoiding the food effect. The question was whether the claim required the modified release mirabegron formulation to possess a particular pharmacokinetic profile (a reduction in either Cmax or Cmax and AUC) which would lead to a reduced food effect, or whether the effect of the modified release was only relevant when considering the technical benefit of the claimed formulation. Mellor J held that the term “a pharmaceutical composition for modified release” had a special meaning in the claim because of definitions contained in the description, and therefore included the beneficial impact on the pharmacokinetic profile. As such, successful enforcement required a demonstration of this feature compared to conventional mirabegron formulations. While one defendant, Teva, had admitted infringement for their existing product (with a declaration of non-infringement (DNI) for a design-around product potentially to be heard at a later date), Sandoz had given no such admission and Astellas failed to meet their burden of proof at trial.

In principle, there is nothing to stop a party pursuing a claim construction on appeal different from that advanced at first instance, provided that no procedural unfairness results (e.g. if the other side were prejudiced by being deprived of the opportunity to adduce evidence they might otherwise have relied upon). There was a dispute about whether InterDigital had changed its position on appeal in the Trial B litigation between InterDigital and Lenovo⁷. However, Arnold LJ was not fazed: the correct interpretation of the claims of a patent is an issue of law for the court to determine and the court is not bound to accept either party's construction, either at first instance or upon appeal. As matters unfolded in the appeal, Arnold LJ took a slightly different construction to that adopted by Mellor J, below. Whilst this did not matter for essentiality/infringement, it was material to the consideration of novelty and had the effect of reversing Mellor J’s finding that the patent was anticipated by a marked-up version of a technical standard (3GPP TS 25.309 v6.2.0) called Filiatrault. As a result, InterDigital’s appeal was allowed.

More than twenty years ago, the Court of Appeal decided in Coflexip⁸ that when interpreting the wording of a product claim, the word “for” meant “suitable for”, such that an accused product would infringe whether or not it was actually performing the ascribed purpose, otherwise the clear intention of the patentee to have a product claim would be defeated. The Court of Appeal in Optis v Apple⁹ was fully cognisant of Coflexip when it decided the appeal in the context of Optis’ patents for a physical uplink control channel. The claim at issue was a product claim – a mobile phone – which required the device both to spread and transmit signals, but not both at once. “Spreading” took place in accordance with a code multiplexing structure (CMS). Birss LJ noted that “Coflexip is illustrative but cannot be taken too far. That is because in the end the issue is always and only a matter for the true construction of the patent in question.” However, given the nature of the claim, he followed Coflexip by upholding Meade J’s decision below¹⁰ that the mobile device must be capable of operating with the relevant CMS when required to do so but is not limited to a situation in which that CMS is in fact in use. Thus oriented, Birss LJ also upheld Meade J’s findings on infringement and validity, thereby dismissing Apple’s appeal completely.

Claim construction was the “most difficult issue to decide” when Charlotte May KC sat as a Deputy High Court Judge in Ensygnia v Shell¹¹. The Deputy Judge’s consideration of the issue began with deciding an apparently novel point of law: whether the description of embodiments said to be excluded from the scope of the claim should be excised from the specification when considering the meaning of the claim language, or whether the claims should be read in light of the whole description. The Deputy Judge preferred the latter approach, notwithstanding the lack of any helpful authority provided by the parties. Proceeding to interpret the claim language, the Deputy Judge referred to the three key considerations identified by Arnold LJ earlier in the year in InterDigital v Lenovo¹²: (i) the wording of the relevant integer of the claim, (ii) the context provided by the specification and (iii) the inventor’s purpose.

The main point in dispute was whether the printed QR codes affixed to petrol pumps on Shell’s forecourts fulfilled the claim integer “wherein the display is a sign”. The other words of the claim made it clear that the display was part of the computing apparatus. However, the only passage of the patent’s description which dealt with the meaning of “sign” said that electronic displays were outside the scope of the claim, notwithstanding that the claim’s features related to an electronic display. This conflicting teaching led the Deputy Judge to express her conclusion “after anxious consideration and with some hesitation” that a printed sign was within the claim, bearing in mind the inventor’s purpose. Ultimately, the result of this finding was that the patent was invalid: the amendments which limited the meaning of “sign” to a non-electronic sign were not clearly and unambiguously disclosed in the application as filed and in addition for being bad for added matter under s. 72(1)(d), the claim also failed for having an extended scope of protection under s. 72(1)(e) of the Act.

In Vernacare Limited v Moulded Fibre Products Limited¹³ in the Court of Appeal, Sir Christopher Floyd held that the Judge below had erred when determining the inventive concept of one of the claims by introducing an additional purpose-based element into the claim, with the result that the construction wrongly excluded a detergent resistant washbowl that was made for reasons other than achieving detergent resistance. When the inventive concept was properly formulated as a washbowl made from paper pulp containing a fluorocarbon (rather than a detergent-resistant washbowl so made), the claim was obvious over the cited prior art and an independent claim was also invalid in light of the expert evidence.

Infringement under the doctrine of equivalents

Where does purposive construction end and infringement by equivalents begin? As readers will remember, the original Improver¹⁴ questions, designed to be a framework for purposive construction, included consideration of whether the variant has a material effect on the way the invention works (Improver question 1). Actavis¹⁵ took that concept of “immaterial variants” and turned it into a series of three separate questions, thereby creating the doctrine of equivalents. So should the courts still consider the material effect of a variant under purposive construction?

If they do, perhaps unsurprisingly, there will be cases where the outcome of the application of purposive construction and the doctrine of equivalents is the same. In Heraeus v First Light Lamps¹⁶, a case concerned with a sealing method for glass tubes, Zacaroli J considered that one of the factors used to construe the claim purposively included whether the variant would have a material effect on the way in which the invention worked. Indeed, the Judge noted that “the parties were agreed that although the question raised by a case on infringement by equivalents is logically distinct from that raised when purposively construing a patent (Actavis, above, at §56), on the facts of this case there is no material difference.”

More often, infringement cases based on a normal construction and on the doctrine of equivalents will be entirely distinct. By way of example, in Philip Morris Products v Nicoventures¹⁷, Nicoventures (BAT) had conceded that Philip Morris’ IQOS ILUMA product did not infringe the patent in suit on a normal construction so the case turned on the application of the doctrine of equivalents.

The decision on equivalents turned on the third Actavis question and in particular whether an embodiment disclosed but seemingly incompatible with the claim language meant not only that such an embodiment was outside the normal meaning of the claims but also that there was no infringement by equivalents. Here, HHJ Hacon found the inventive concept of BAT’s patent to be “An HNB [heat not burn] system in which (i) an article containing smokeable material is inserted into the heating zone of a heating apparatus, (ii) the smokable material is heated by inductive heating and (iii) the maximum temperature of the heater in the apparatus is exclusively determined by a Curie point of the heating material”. He construed “exclusively determined” to mean that there must at all times be a fixed relationship between a Curie point of the heater material and the maximum temperature of the heater.

The PMI product differed from the inventive concept in that (a) the heater is in the consumable and (b) the maximum temperature of the heater is not at all times fixed by reference to a Curie point of the heating material because it depends in part on whether the system is calibrating. The Judge considered these two differences collectively in determining whether PMI’s product infringed as an equivalent (the approach he endorsed in Regen v Estar¹⁸) and had little difficulty in answering the first and second Actavis question in the affirmative: the way the Curie point is used in the IQOS ILUMA and the fact that its heater is in the consumable meant the same result was achieved in the same way as the inventive concept.

On the third question, the specification of BAT’s patent disclosed and illustrated an HNB system in which the heater is in the consumable (as in the IQOS ILUMA). Applying the “disclosed but not claimed” principle, HHJ Hacon found that “Without exception, the method, apparatus and system claims require the heater to be in the apparatus, not in the consumable.” As a matter of policy, he held that embodiments disclosed but not claimed must be available to the public to use freely: “Where … the patentee says in the description that the technical effect identified can be achieved either by means A or B but goes on to claim only means B, this is a clear indication from the patentee that means A does not fall within the scope of the claims, whether as a matter of normal construction or equivalence. Any other approach to construction would sanction patents likely seriously to mislead the public.” The answer to the third Actavis question was therefore yes and there was no infringement by equivalents.

The Formstein defence - where infringement arguments that are based on equivalents cannot succeed because a piece of prior art would also infringe under the same analysis – is now established in English law. Having been mentioned in 2019 by HHJ Hacon in Technetix v Teleste¹⁹, and blessed as a principle in 2021 by Birss LJ in Facebook v Voxer²⁰, it was applied for the first time as a successful defence in 2022 by Mr Nicholas Caddick KC, sitting as Deputy High Court Judge in Vernacare Limited v Moulded Fibre Products Limited²¹. The Formstein defence was one of the bases on which the Judge found one of two patents in suit valid and not infringed. Infringement of the second patent (also held valid) was admitted. 

Unfortunately for practitioners interested in the Formstein defence, Nicholas Caddick KC’s findings on the first patent were not appealed when Vernacare came before the Court of Appeal²². However, as mentioned above, Sir Christopher Floyd reversed the Judge’s findings on the second patent, having taken a different view on claim construction.

Notwithstanding that it wasn’t part of the appeal in Vernacare, the Formstein defence did get an outing in 2023, being held by Bacon J to be available to PCI-Pal in defending an infringement case brought by Sycurio in relation to its patent concerned with the processing of telephone calls within a call centre²³. However, in this case, because the workings of PCI-Pal’s system were considered confidential (and therefore redacted from the judgment) it is not clear exactly how the Formstein defence was dealt with.

De minimis

More often mentioned in limericks concerning a young lawyer called Rex than in patents court cases, the defence of de minimis non curat lex made a brief appearance in 2023 when it was argued that one example of an infringing item which fell outside the specified target manufacturing tolerances was sufficient evidence to justify a finding of infringement. This was put forward in Heraeus v First Light Lamps²⁴, Heraeus arguing that the number of infringing items was relevant only to the quantum of damages. Zacaroli J applied Napp v Dr Reddy's²⁵ and held that, even if the item had been infringing (which was not made out on the evidence), the patentee had failed to establish that infringement occurred on more than a de minimis number of occasions. It was not enough to suggest that “mistakes do happen” without providing any statistical basis for how often they might happen in practice.

Continue reading the other sections in publication:

1. Claim construction and infringement
2. Validity
3. FRAND
4. Supplementary protection certificates (“SPCs”)
5. Procedural issues
6. Unitary Patent/Unified Patent Court

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