Introduction
Prevalence of doctrine
Actavis test
Literal to normal to purposive meaning
What does this mean for patent holders and market entrants?
The 'doctrine of equivalents' (ie, the principle that a patent may be infringed by a product or process which is considered equivalent to that protected by the granted patent) was not historically adopted by the UK courts. Unlike the United States and certain European jurisdictions, the doctrine of equivalents arrived in UK patent law only following the landmark Supreme Court decision in Actavis UK v Eli Lilly(1) in 2017.
In Actavis, the Supreme Court significantly reformulated the test for patent infringement, moving from a wholly purposive interpretation of the claims to a two-limb approach: 'normal' interpretation of the claims and a doctrine of equivalents. Now, four years on from that decision, this article considers the post-Actavis development of the doctrine, recent trends and implications for litigants in the United Kingdom (for a discussion of the implications of the doctrine on the life sciences sector, please see "Doctrine of equivalents – how 'new normal' approach affects life sciences").
Over the past four years, there has been a clear increase in the number of patent disputes in which infringement by the doctrine of equivalents is pleaded. By 2019 the doctrine of equivalents was relied on more frequently and successfully. For instance, infringement on the basis of the doctrine of equivalents was found in Regen v Estar,(2) which was related to a blood plasma product, and Eli Lilly v Genentech,(3) which concerned a patent that covered a specific human antibody for the use in the treatment of rheumatoid arthritis and psoriasis (and where infringement was also found on the basis of a normal interpretation).
Importantly, by 2019 it became clear that the doctrine of equivalents was not limited to life sciences patent cases. Infringement on the basis of the doctrine of equivalents was also found in non-life sciences cases, including Marflow v Cassellie,(4) which concerned a method of installing shower fittings, Technetix v Teleste,(5) which was to do with a cable tap unit for modifying cable TV signal, and Mishan v Hozelock,(6) which related to expandable hoses (although the patent was held to be valid only in Marflow).
Further, the doctrine of equivalents was successfully deployed in the telecoms sector in Conversant v Huawei, a case that concerned standard essential patents and fair, reasonable and non-discriminatory terms.(7)
By 2020 the number of cases in which the doctrine of equivalents was deployed increased again, with infringement on this basis succeeding in the majority. Such cases include Evalve v Edwards,(8) which concerned a transcatheter valve repair device, Edwards v Meril,(9) which related to two patents for heart valve devices (although one patent was held to be invalid and the second patent was held to be partially invalid), and Freddy v Hugz,(10) which concerned women's jeans. The outlier is Akebia v Fibrogen,(11) which related to the use of enzyme inhibitors for the treatment or prevention of anaemia in which the infringement arguments failed.
The doctrine of equivalents is therefore now a dominant feature in most UK patent cases, further reinforced by 2021 decisions including the Court of Appeal's decision to uphold the High Court's finding that the patent in suit in the leading telecoms case IPCom v Vodafone(12) was infringed by the doctrine of equivalents (for further details please see "Crown use: a royal defence to patent infringement?"). Litigants will have to consider the wide-ranging implications that this will have on their strategy to protect their patent portfolio or clear the way for market entry. In particular:
- the scope of the patents may not be limited to the wording of the claims;
- equivalents may play a role in invalidity by providing a check against whether the invention was novel or inventive; and
- while claim construction is within the remit of the court, expert evidence may play an increased role.
In Actavis, the Supreme Court introduced its new two-stage test for infringement.
Stage 1 – 'normal' infringement
The first stage considers whether there is so-called 'normal' infringement – in other words, "does the variant infringe any of the claims as a matter of normal interpretation?".(13) There has been debate about the meaning of 'normal' infringement and questions of whether it meant literal infringement. Later cases set out that 'normal' means taking a so-called 'purposive' approach: what the person skilled in the art would have understood the patentee to be using the language of the claim to mean.(14) Where the answer to Stage 1 is 'no', Stage 2 is considered.
Stage 2 – infringement by equivalents
The second stage involves a consideration of whether "the variant nonetheless infringe[s] because it varies from the invention in a way or ways which is or are immaterial".(15) To answer this, the following three questions must be considered:
- Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention (ie, the inventive concept revealed by the patent)?
- Would it be obvious to the person skilled in the art, reading the patent at the priority date but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention?
- Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention?
These three questions are commonly referred to as the 'Actavis questions'. The answers to these questions must be 'yes', 'yes' and 'no', respectively, for a finding of infringement based on equivalents.
The interpretation of these questions has been subject to much commentary in the cases that followed Actavis.
Literal to normal to purposive meaning
In Icescape v Ice World,(16) the Court of Appeal recast the Actavis questions. Question 1 received the most judicial attention, with Lord Justice Kitchin holding that 'literal meaning' should be read to mean 'normal meaning'.
However, despite this change, the term 'literal meaning' remained part of Actavis Question 3. It was not until later, in Akebia, where Lord Justice Arnold pointed out that if Actavis Question 1 is talking about 'normal meaning', all of the Actavis questions should refer to 'normal meaning'. But what does 'normal' mean? Mylan v Yeda,(17) Illumina v MGI(18) and Icescape all established that 'normal meaning' means a 'purposive' interpretation.
Question 1: what is the inventive concept?
As Lord Justice Arnold explained in Akebia, Question 1 is:
partly a question of interpretation of the specification (what is the inventive concept revealed by (the relevant claim(s) of the patent?) and partly a question of fact (does the variant achieve substantially the same result in substantially the same way?(19)
It is the former part of this question which leads to the most difficulties. What is the inventive concept, if not confined to the wording of the claims? This begs the question of what should be considered when determining the inventive concept under Question 1?
Prosecution history estoppel
In the United States, which has a well-established doctrine of equivalents, the courts look to the specification but also to the prosecution history of the patent to determine whether the patentee has made any amendments or comments that would indicate the limits of the scope of the claim. In the United Kingdom, the Supreme Court in Actavis set out only limited circumstances in which the court may refer to the patent prosecution history in respect of equivalents.
The prosecution file history may be considered only where either the point of construction is truly unclear, and the contents of the prosecution file unambiguously resolve it, or it would be contrary to the public interest to ignore the contents of the file.
In reality, so far, the UK courts have been reluctant to consider the prosecution file history. In the aforementioned cases of Regen, Illumina and Icescape, although prosecution history was raised where there was a clear case of the patentee choosing to delete claims to avoid a problem raised by the examiner, it was decided that this was not sufficient to allow for the prosecution history to be taken into account.
The one exception is Akebia, in which the prosecution history was considered on the basis that it would be contrary to public interest for it to be ignored. The patentee had contended that if the patent were granted it would not seek to broaden the scope of the patent to other heterocyclic carboxamides beyond the confines of Formula (I) of the claim, which was precisely what it then intended to do in the UK infringement case. This was a fairly clear-cut case of the patentee reneging on its representations to the European Patent Office (EPO). In more nuanced cases, the court may revert to its primary position not to review the prosecution history.
Beyond the claims
The Supreme Court's reference to "inventive concept" in Actavis (also referred to as the "essence" or "core" of the invention in other cases) confirmed that the focus of the infringement analysis should no longer be on the claim language, but should be directed to the inventive concept of the claim when considering whether a variant would infringe. There is a distinction between the invention as a whole, which is claimed, and the inventive concept, and this distinction matters. As HHJ Hacon explained in Regen:
The invention is that which is claimed, see s.125(1) of the Patents Act 1977. I take the inventive concept or core of the invention to be the new technical insight conveyed by the invention – the clever bit – as would be perceived by the skilled person. This will be assessed by reference to the specification and the evidence.
This has fuelled the fire by suggesting that a patent protects more than the claimed invention; instead, it protects the "inventive concept". This is identified by the specification and "evidence". This begs the further question of what evidence is admissible? Possibly not the prosecution history. Perhaps, then, the state of the art must be considered.
Should prior art be considered?
The question arises whether the inventive concept is something which can be identified from reading the patent alone or whether it depends on what prior art is cited against it.
In Icescape, it was held that the correct approach is how the patent would be read with knowledge of the state of the art. This approach would suggest that in order to come to a view on infringement, validity must first be considered.
The inventive concept has traditionally been part of the obviousness consideration under the Pozzoli(20) approach. The question then arises with the Actavis questions as to whether the inventive concept for infringement purposes is the same as for validity purposes.
In the cases of Yeda and Fisher v Paykel,(21) the courts held that the doctrine of equivalents is not relevant to validity. However, in the more recent case of Liqwd Inc v L'Oreal,(22) Mr Justice Birss (as he then was) commented: "I will say only that I can see room for arguing that for validity purposes some account ought to be taken of the wider [Actavis claim] scope."
This question was again posed to Lord Justice Arnold recently in Akebia, but he did not need to answer it, given his other conclusions in the case. This therefore remains a live issue which has not been resolved in case law.
However, it appears that the door is open for alleged infringers to use squeezes between the inventive concept determined under the doctrine of equivalents and obviousness to advance their case.
Such tactics are not uncommon. Use of the so-called 'Gillette defence' (ie, that if a patent covers a product or process, it must also lack novelty or an inventive step over the prior art) is well established. It remains possible that parties may seek to use a Gillette defence in the context of equivalents (ie, if the patent covers the variant, it must also lack novelty or an inventive step over the prior art).
Patentees and alleged infringers may therefore now need to consider both elements prior to bringing or defending an infringement claim.
Practical consequences
Future litigation is likely to focus on the scope of the inventive concept. The early engagement of an expert in the field of technology of the patent is likely to be essential for parties seeking to establish the inventive concept of the patent. Such an expert will be able to provide insight not only into what the claims say, but also what the real essence or core invention is.
Patentees may seek to argue a broader inventive concept to capture infringements. However, patentees must be wary of overstretching or they may fall foul of potential invalidity arguments (either obviousness or insufficiency). Testing the veracity of the patent to stand up to the scrutiny of a validity challenge will be a key part of the assessment for determining the scope of the inventive concept, regardless of whether the court explicitly considers the two as synonymous.
At an earlier stage, patentees should also take care to clearly characterise and define the inventive concept of the patent in their application and avoid making explicit comments which exclude certain variants in prosecution that could be used against them in later litigation.
Question 2: does this question matter?
If the court has answered 'yes' to Question 1, it has determined that the variant achieves substantially the same result in substantially the same way. When moving to Question 2, with the knowledge that the variant achieves substantially the same result as the invention, in most cases it will be logical that the skilled person will think it is obvious that the variant does so in substantially the same way as the invention. As Lord Justice Arnold pointed out in Akebia: "[g]iven the way in which question (ii) has been formulated by the Supreme Court, there will rarely be scope for a negative answer [to question 2] if the answer to question (i) is 'yes'."
This question therefore seems largely redundant.
Question 3: checks and balances
Once the court has gone as far as deciding that the variant works in substantially the same way as the core invention (under Question 1), it may be difficult for the court to then say that strict compliance is intended, so that there is no infringement based on equivalents. This has been demonstrated in a number of cases, including Regen, Technetix, Marflow and Hozelock.
However, this question acts as a check on the first two, to consider whether there is anything that indicates that the patentee intended strict compliance.
The court indicated in Hugz that such evidence will likely involve an "item of prior art acknowledged by the patent, or a piece of common general knowledge, that the patentee would, in the view of the skilled person, wish to avoid". This again indicates the potential interaction between validity and the doctrine of equivalence.
It also raises the question of whether the prosecution history could feed into Question 3. In Regen, HHJ Hacon indicated that it could when he said in relation to Question 3 that "there remains the possibility that the prosecution history restricts Regen's room for manoeuvre in relation to the scope of the claim". However, neither requirement of Lord Neuberger in Actavis were fulfilled, so the prosecution history was said not to affect the scope of the claim.
What does this mean for patent holders and market entrants?
Over the past four years since the Actavis decision, the doctrine of equivalents has played a growing role in patent infringement proceedings in the United Kingdom. Immediately following Actavis, there was a slightly slow uptake of this principle, but by 2019 the number of cases where patentees were relying and succeeding on equivalents had increased.
The outcome of recent cases has been varied as the lower courts have interpreted the Actavis questions, applying them to wide-ranging cases in life sciences, but also other sectors. However, what it is clear is that the doctrine of equivalents is now firmly established as a feature of UK infringement proceedings. This means that parties will have to consider their position with the assistance of experts early on and, following Facebook v Voxer,(23) specifically plead it in their particulars of infringement.
Companies will also have to consider the impact of this new doctrine on patent drafting. They should be mindful not just of the claimed invention, but also of the core technical concept and how well this is outlined in the specification. Further, patent attorneys will have to take care of the potential implications of making concessions at the EPO, should the prosecution history be factored into infringement proceedings. While this has not been widely used, now that the doctrine is in play, there is potential for case law to develop in this area.
Finally, while there has been success in running equivalence arguments in main infringement proceedings, the UK courts have not yet granted an interim injunction on the basis of the doctrine of equivalents. There is no obvious reason why this would not be possible, but it remains to be seen what appetite the court will have to hear these more complex arguments in a preliminary injunction setting. Could it lead to the court issuing more preliminary injunctions to maintain the status quo until the infringement case has been heard in full, or would damages be seen as an adequate remedy? The specific facts of a case will be highly relevant, but the complexity of determining whether a variant is equivalent or not, without the assistance of expert evidence and cross-examination, is likely to weigh in the balance when the court makes its assessment.
For further information on this topic please contact Tracey Roberts, Sarah Taylor or Katie Lo at Pinsent Masons by telephone (+44 20 7418 8250) or email ([email protected], [email protected] or [email protected]). The Pinsent Masons website can be accessed at www.pinsentmasons.com.
Endnotes
