18 November 2021

Are We Moving Closer to Anticipation by Equivalence?

The landmark decision in Actavis v Eli Lilly (Actavis) in July 2017 changed the United Kingdom’s approach to the scope of protection of patent claims and introduced equivalents when considering patent infringement. The law in this area continues to evolve and recent cases suggest that the approach to validity may now consider equivalence.

The most important decision in UK patent law in recent years was the Supreme Court’s decision in Actavis. Actavis was concerned with infringement by equivalents and subsequent cases made it clear that purposive claim construction remained the correct approach when considering novelty. However, nearly four years later, the UK courts are starting to consider the wider issues and what the so-called doctrine of equivalents may mean for assessments of novelty in the future. In this article we look at some of the recent decisions of the High Court and consider what this may mean for patentees going forward.

The Supreme Court’s decision in Actavis¹

The doctrine of equivalents is a legal principle established in Actavis, where the Supreme Court defined how the scope of protection should be assessed and this can mean it is widened beyond the normal interpretation of the claim when considering infringement by variants. In particular, instead of only purposively construing the claims, the Supreme Court considered infringement using a new two-part test:

(1) Does the variant infringe any of the claims as a matter of normal interpretation? If not,

(2) Does the variant nonetheless infringe because it varies from the invention in a way which is immaterial?

The second limb of the Supreme Court’s approach involves applying the reformulated Improver² questions. Of particular note is the notional addressee of the patent is now imbued with the knowledge that the variant does indeed work when considering whether it would have been obvious that it achieved the same result in the same way. Prior to this case and since the House of Lords’ judgment in Synthon³ , it was a settled legal principle of patent law in the UK that claims should be interpreted in the same way when considering either validity or infringement.

The UK courts start to consider the approach to validity

As Actavis only considered claim construction for the purposes of infringement, there has been much speculation as to how far the doctrine of equivalents would apply to novelty when validity is being assessed. In the months following Actavis, the High Court started to consider whether an equivalent, or variant, in the prior art would be enough to destroy novelty and overturn the patent in question. Some of these decisions are discussed briefly below.

In Mylan v Yeda⁴ (Mylan), the claimants sought revocation of the defendants’ patent by arguing that a piece of prior art disclosed an equivalent dosage regime that anticipated the claims and so destroyed novelty. The defendants’ position was that settled law meant that the claim would only lack novelty if the subject-matter disclosed by the prior art fell within the claim as purposively construed.

In his judgment, Arnold J. (as he then was) concluded that the Supreme Court had intended the first limb of the Actavis questions to still require the claim to be construed in order to determine what the person skilled in the art would have understood (i.e. purposive and not literal construction). When considering the second limb of the test, Arnold J. went on to say (albeit in obiter) that until the Supreme Court considers patent validity again, the doctrine of equivalents does not extend to the assessment of novelty and that purposive claim construction remained the correct approach.

In the later case of Fisher & Paykel v ResMed⁵ (Fisher), the claimants argued that the claims (relating to masks used to treat obstructive sleep apnoea) had a broad scope of protection and so were anticipated by the prior art, while the defendants argued for a narrower interpretation. In finding the defendants’ patent to be both anticipated by the prior art and obvious, Richard Meade QC (as he then was) sitting as Deputy High Court Judge, concluded that in the absence of a decision of a higher court, the approach taken by Arnold J. in Mylan was correct and that the “normal interpretation” required by the first limb of the test requires purposive construction.

In addressing the second limb and the reformulated Improver questions, the judge stated that in his view the Supreme Court had equated “literal meaning” with “normal meaning” for the purpose of the reformulated questions. Although the judge did not give a view on whether a claim can actually be anticipated by a variant, he stated that it was an arguable view which will need to be considered by a higher court in due course.

Optis v Apple

In the recent licensing dispute Optis v Apple, Mr. Justice Meade had to decide at the end of a technical trial whether Optis’ standard essential patent (SEP) was invalid for novelty. The SEP, relating to a mechanism for radio link control polling within Long Term Evolution networks, had previously been held valid by Mr. Justice Birss and later by the Court of Appeal in the Unwired Planet v Huawei dispute in 2015.

Although the SEP in question had been subject to earlier litigation, the Court had to consider the validity of the SEP afresh, in light of the new prior art before it. Apple argued, unsuccessfully, that the SEP was anticipated by the prior art, including an argument of anticipation by equivalence in the event that a piece of new prior art was not found to anticipate the SEP’s claims under ordinary construction. In effect, Apple argued that the disclosure of the prior art was an immaterial variation of the invention claimed by the SEP in dispute. Although on the facts the judge rejected Apple’s arguments on other grounds, he stated that a finding of anticipation by equivalence was not available in any event as Apple had not provided detailed legal argument and the position on equivalence had only been introduced at a late stage in proceedings by way of amendment. However, the judge considered how the doctrine of equivalents may apply to patent validity attacks in the future and stated that when an argument of anticipation by equivalence is advanced “it will need to be fully argued, including with reference to the law of other EPC jurisdictions and with how and whether people can be prevented practising the prior art, or if not, how and why not.

Although the judge was clear that anticipation by equivalence was not available, he nevertheless proceeded to answer the reformulated Improver questions to determine if the prior art would fall within the scope of the SEP’s claims, concluding that the anticipation by equivalence argument would have failed, even if it had been available. In relation to question 1, Mr. Justice Meade considered that the prior art did not achieve substantially the same result as the SEP because the SEP avoided the issue of “prior polling”. In relation to question 2, the judge stated that there was no issue as to whether the skilled person would understand the prior art. Finally, in considering question 3, the judge said that if he was wrong in relation to question 1, strict compliance with at least one of the disputed claim features was intended.


To date, only alleged infringers have attempted, albeit unsuccessfully, to take advantage of the change to the law brought about by the decision in Actavis when pursuing revocation actions and challenging novelty. Although the outcome in Optis v Apple, as well as in Mylan and Fisher, was not in the end materially affected by the decision in Actavis and the new law concerning equivalents, it is only a matter of time before a case presents where these issues prove critical and need to be fully addressed.

It is not certain that the law will evolve to consider equivalents in validity disputes though, because, as highlighted by Lord Justice Birss in the recent Facebook v Voxer case, the issues are complex. In that case, Birss LJ considered (obiter) the question of whether a Formstein defence (that an alleged equivalent lacks novelty or is obvious so that the claim scope must be confined to its normal construction in that respect) exists in English law. Had it been necessary, his Lordship would have held that such a defence does exist in English law and would have led to the conclusion that Voxer could not rely on the doctrine of equivalents in this case. The judge explained that if a patent is infringed under the doctrine of equivalents, then the scope of protection afforded by the patent could be confined to a normal interpretation if a broader interpretation under the doctrine of equivalents would render the patent invalid. In his reasoning, Lord Justice Birss said that it would be harsh to invalidate a claim using the doctrine of equivalents if the claim is valid on its normal construction. He was also concerned to promote certainty, which is always welcome. However, we expect these arguments to continue to be raised until fully addressed at the appellate level.

Foretelling how a claim may eventually be construed during any future litigation is an important consideration many years earlier during patent prosecution and at present, there is uncertainty on how far equivalents may adjust our law and thinking. These recent decisions of the High Court show us how things may evolve, but only the Court of Appeal or ultimately the Supreme Court can settle things. In the meantime, it is likely that claimants in patent revocation actions will continue to seize every opportunity to exploit the argument where it serves their interests.

1. Actavis UK Limited and others v Eli Lilly and Company [2017] UKSC 48
2. Improver Corporation v Remington Consumer Product Limited [1990] F.S.R. 181
3. Synthon BV v SmithKline Beecham plc [2005] UKHL 59
4. Generics (UK) Ltd (t/a Mylan) & Synthon v Yeda Research and Development Co Ltd & Teva Pharmaceutical Industries Ltd [2017] EWHC 2628 (Pat).
5. Fisher & Paykel Healthcare Ltd & Anor v ResMed Ltd & Anor [2017] EWHC 2748 (Ch).
6. Optis Cellular Technology LLC & others v Apple Retail UK Limited & others [2021] EWHC 1739 (Pat)
7. Facebook Ireland Limited v Voxer IP LLC [2021] EWHC 1377 (Pat)