Supreme Court firmly establishes UK doctrine of equivalents

Significant changes in the way we determine claim scope in the UK.

In its decision in Actavis UK Limited & Others v Eli Lilly and Company [2017] UKSC 48 issued earlier this year, the UK Supreme Court made a significant move from the established principals of claim construction and introduced a doctrine of equivalents into UK patent law.  Here we review the details of the case and what the change means for patentees and those seeking to work around third party rights.

Key takeaways:

  1. We now have a doctrine of equivalents that must be considered when assessing claim scope.
  2. Claims may generally be considered to encompass unclaimed variants that differ immaterially from and work in the same way as what is claimed.
  3. Acts that didn’t infringe a patent before this decision might now infringe. Any conclusions drawn on freedom to operate in the United Kingdom prior to this judgement should be reconsidered.

What happened?

The case concerned Eli Lilly’s European patent number 1313508 (“the Patent”), claims 1 and 12 of which define:

“1. Use of pemetrexed disodium in the manufacture of a medicament for use in combination therapy for inhibiting tumor growth in mammals wherein said medicament is to be administered in combination with vitamin B12 or a pharmaceutical derivative thereof, said pharmaceutical derivative of vitamin B12 being hydroxocobalamin, cyano-10-chlorocobalamin, aquocobalamin perchlorate, aquo-10-chlorocobalamin perchlorate, azidocobalamin, chlorocobalamin or cobalamin.”


“12. A product containing pemetrexed disodium, vitamin B 12 or a pharmaceutical derivative thereof said pharmaceutical derivative of vitamin B12 being hydroxocobalamin, cyano-10-chlorocobalamin, aquocobalamin perchlorate, aquo-10-chlorocobalamin perchlorate, azidocobalamin, chlorocobalamin or cobalamin, and, optionally, a folic binding protein binding agent selected from the group consisting of folic acid, (6R)-5-methyl-5,6,7,8-tetrahydrofolic acid and (6R)-5-formyl-5,6,7,8-tetrahydrofolic acid, or a physiologically available salt or ester thereof, as a combined preparation for the simultaneous, separate or sequential use in inhibiting tumor growth.”

Actavis’ proposed products included pemetrexed compounds in combination with vitamin B12.  The products were for use in the treatment of cancer.  The key difference between the Actavis products and the medicaments defined in Eli Lilly’s claim 1 was the use of pemetrexed, pemetrexed ditromethamine, or pemetrexed dipotassium, instead of pemetrexed disodium.

The positions of each party were summed up by Lord Neuberger in the judgement, stating:

“In a nutshell, the rival contentions are these. Lilly argues that the Actavis products infringe the Patent because they are medicaments to be used as a treatment for cancer consisting of pemetrexed diacid, or a pemetrexed salt, with vitamin B12, which represents the essence of the teaching and claim of the Patent. By contrast, Actavis argues that their products do not infringe because the claims of the Patent are limited to a specific pemetrexed salt, namely pemetrexed disodium, and the Actavis products contain either pemetrexed diacid or different pemetrexed salts.”

Put simply, the question to be answered was whether pemetrexed disodium as claimed should be construed to cover pemetrexed itself or other salts thereof, or whether it should be interpreted as meaning pemetrexed disodium, specifically.

Claim construction

Prior to this judgement, the law on patent infringement in the UK had been shaped by three key decisions: Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183 (“Catnic”), Improver Corporation v Remington Consumer Products Ltd [1990] FSR 181 (“Improver”) and Kirin-Amgen Inc v Hoechst Marion Roussel Ltd [2005] RPC 9 (“Kirin-Amgen”).  Those decisions established that, when assessing infringement, a “purposive” construction should be applied to the claims, considering what a skilled person would have understood the patentee to be using the words to mean.

Rather than simply applying purposive construction in this case, though, the Supreme Court returned to first principles to decide how the claims should be construed.  The law on claim interpretation in the UK is based on Article 69(1) European Patent Convention, which states:

“The extent of the protection conferred by a European patent or a European patent application shall be determined by the claims. Nevertheless, the description and drawings shall be used to interpret the claims.”

If one simply applies the literal meaning of claims 1 and 12, the scope of protection would appear to be quite clearly limited to pemetrexed disodium.  Articles 1 and 2 of the Protocol on the Interpretation of the EPC explains that it isn’t enough to just apply the literal meaning, though.

Article 1

General principles

Article 69 should not be interpreted as meaning that the extent of the protection conferred by a European patent is to be understood as that defined by the strict, literal meaning of the wording used in the claims, the description and drawings being employed only for the purpose of resolving an ambiguity found in the claims. Nor should it be taken to mean that the claims serve only as a guideline and that the actual protection conferred may extend to what, from a consideration of the description and drawings by a person skilled in the art, the patent proprietor has contemplated. On the contrary, it is to be interpreted as defining a position between these extremes which combines a fair protection for the patent proprietor with a reasonable degree of legal certainty for third parties.

Article 2


For the purpose of determining the extent of protection conferred by a European patent, due account shall be taken of any element which is equivalent to an element specified in the claims.”[1]

Lord Neuberger explained that Articles 1 and 2 of the Protocol mean that the scope of protection is not to be limited by the literal meaning of the claims and that there is, potentially, a difference in interpreting a claim and the extent of protection afforded by a claim. In assessing the extent of protection afforded, equivalents must be considered.

Having reviewed the case law in the UK (Catnic, Improver and Kirin-Amgen) as well as the approach taken in other EU jurisdictions, Lord Neuberger concluded that the problem of variants is best approached by considering two questions, through the eyes of the person skilled in the relevant art:

“(i) does the variant infringe any of the claims as a matter of normal interpretation; and, if not,

(ii) does the variant nonetheless infringe because it varies from the invention in a way or ways which is or are immaterial?

If the answer to either issue is “yes”, there is an infringement; otherwise, there is not.”

He explained that question 1 is a matter of interpretation, and can be achieved using the standard process for interpreting documents.  Applying that question to the current case, he concluded:

“In the present case, there is no doubt that, according to normal principles of interpreting documents, the Actavis products do not infringe the Patent, as in no sensible way can pemetrexed free acid, pemetrexed ditromethamine, or pemetrexed dipotassium mean, ie be said to fall within the expression, “pemetrexed disodium” in claim 1 of the Patent…”

Turning to the second question, Lord Neuberger returned to the three questions provided by Hoffman J (as was) in Improver.  Whilst he found these helpful, he reformulated the questions, noting, though, that they should be used as guidelines, rather than strict rules.  The reformulated questions are:

 “i) 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, i.e. the inventive concept revealed by the patent?

ii) 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?

iii) 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?

In order to establish infringement in a case where there is no literal infringement, a patentee would have to establish that the answer to the first two questions was “yes” and that the answer to the third question was “no”.”

Lord Neuberger applied the questions to the Actavis products, coming to an interim conclusion of direct infringement.  He stated that the products work in the same way as the invention and that it would have been clear to the notional addressee, once informed that the variants do indeed work, that the variant products would work in the same way.  On the third question, he concluded that the notional addressee would understand that the reason the claims were limited to pemetrexed disodium was that it was the only salt on which the experiments described in the specification had been carried out, rather than to exclude other salts from the scope of protection.

What about the file history?

The question of whether the prosecution history of the file should be considered was raised, Actavis contending that the prosecution history made it clear that the Patent claims should be interpreted as being limited to pemetrexed disodium.  Lord Neuberger addressed this matter, stating:

“In my judgment, it is appropriate for the UK courts to adopt a sceptical, but not absolutist, attitude to a suggestion that the contents of the prosecution file of a patent should be referred to when considering a question of interpretation or infringement, along substantially the same lines as the German and Dutch courts. It is tempting to exclude the file on the basis that anyone concerned about, or affected by, a patent should be entitled to rely on its contents without searching other records such as the prosecution file, as a matter of both principle and practicality. However, given that the contents of the file are publicly available (by virtue of article 128 EPC 2000) and (at least according to what we were told) are unlikely to be extensive, there will be occasions when justice may fairly be said to require reference to be made to the contents of the file. However, not least in the light of the wording of article 69 EPC 2000 [which is discussed above] the circumstances in which a court can rely on the prosecution history to determine the extent of protection or scope of a patent must be limited.

While it would be arrogant to exclude the existence of any other circumstances, my current view is that reference to the file would only be appropriate where (i) the point at issue is truly unclear if one confines oneself to the specification and claims of the patent, and the contents of the file unambiguously resolve the point, or (ii) it would be contrary to the public interest for the contents of the file to be ignored. The first type of circumstance is, I hope, self-explanatory; the second would be exemplified by a case where the patentee had made it clear to the EPO that he was not seeking to contend that his patent, if granted, would extend its scope to the sort of variant which he now claims infringes.”

He also confirmed that the contents of the prosecution file would not cause him to change his mind on infringement of the Patent.

The judgement

Actavis’ products were found to directly infringe the Patent.  Lord Neuberger also considered the issue of indirect infringement, concluding that if the products didn’t directly infringe the Patent, they would indirectly infringe.  He further considered whether the French, Spanish and Italian designations of the patent were directly infringed, again concluding that they were.

What does this mean in practice?

The (re)introduction of a doctrine of equivalents is one of the most significant steps in UK law in recent years and it will take some time to see just how it is applied.  One positive outcome is that the law appears to be more closely aligned with the law of infringement in Germany. This might lower the chances of inconsistency between cases in the UK and other European jurisdictions and between different courts when the UPC comes into effect.

On first glance, the doctrine of equivalents appears to be particularly helpful to patentees, potentially allowing the scope of protection afforded by a claim to be stretched to include variants that would not be covered by a literal interpretation.  Given the EPO’s preference for limiting claims to the scope for which experimental evidence is provided, even though the limitation may not be required for novelty or inventiveness, this may prove useful.  Even though Lord Neuberger indicated that the prosecution history should only be taken into consideration in very specific cases, it would be worth being especially careful in the comments and arguments filed, particularly when limiting claim scope or deleting variants from a claim.  We would encourage patentees to not rely on the doctrine of equivalents, and avoid unnecessarily limiting claims – ideally an infringement should be captured by the literal interpretation of a claim to avoid any doubt.

There is some comment on the effect of the specification on the meaning of the claims in the judgement, but it is insufficient to allow us to draw detailed conclusions on how the doctrine will affect the drafting of specifications.  We would still advise that, where possible, generic definitions are included for each claimed element, along with any known equivalents. Further, we would recommend keeping the doctrine of equivalents in mind when defining claim elements, to avoid causing any equivalents to be accidentally excluded, because they are unnecessarily intimated to be material to the invention or because the specification makes it clear that a narrow interpretation is intended.  It also continues to be beneficial to include more than one exemplified example for each element of the invention, so as to avoid having to limit the claims unnecessarily.

More urgently, it may be necessary to reconsider any conclusions made on freedom to operate, based on the old law.  It is quite possible that acts that previously wouldn’t have infringed might now fall within the scope of a claim if the doctrine of equivalents is applied.

If you would like further information on this, please get in touch with  Rachel Wallis or your usual GB contact.


[1] The Protocol had been amended to include Article 2 after Kirin-Amgen.