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UK Supreme Court grasps nettle of doctrine of equivalents

日期: 31 July 2017

By Hugh Dunlop and Dr. Janet Strath


Eli Lilly v Actavis UK Ltd [2017] UKSC 48 (12 July 2017).

The UK Supreme Court has overturned 35 years of English patent law by applying a doctrine of equivalents to find that Actavis's products directly infringe Eli Lilly's patent.

The Court has reformulated the "Improver" questions originally posed by Lord Hoffmann in Improver Corp v Remington Consumer Products Ltd [1990] FSR 181 (subsequently known as the "Protocol" questions). In doing so, the Supreme Court dealt with some important issues related to patent infringement, including the correct approach to the interpretation of patent claims (particularly in the light of the requirement under the EPC 2000 to take alleged equivalents into account) and also the extent to which it is permissible to make use of the prosecution history of a patent when determining its scope.


The interesting point about this decision is that a variant can now infringe when "it varies from the invention (as claimed) in a way or ways which is or are immaterial", which may leave patent lawyers feeling cast further adrift on a sea of interpretive uncertainty.


This decision is likely to make advising on patent infringement more difficult: practitioners will have to dust off earlier opinions and see if they need to be revised, and there may be a flurry of suits where companies thought they were safe and now find they may infringe.


Background to Lilly v Actavis


Eli Lilly and Company ("Lilly") have marketed pemetrexed disodium as a cancer treatment under the brand name Alimta since 2004, and own European Patent No. 1 313 508 ("the Patent") for the use of pemetrexed disodium in the manufacture of a medicament for use in combination with vitamin B12 (and, optionally, folic acid) for the treatment of cancer, due to expire in June 2021.


Pemetrexed, a member of a class of chemicals known as antifolates, contains two -CO2H units and, therefore, is an acid (hence it is also known as pemetrexed diacid):



Although known to have therapeutic effects on cancerous tumors, pemetrexed can often have seriously damaging (sometimes, even fatal) side-effects when used on its own. The essential disclosure of the Patent was that the damaging side-effects could largely be avoided if a compound called pemetrexed disodium was administered together with vitamin B12. Pemetrexed disodium is known as a salt: it has two -CO2Na units instead of two -CO2H units and, when dissolved in water, the two sodiums separate from the rest of the molecule as positively charged cations, and the rest of the molecule becomes a negatively charged pemetrexed anion.


Actavis intended to market a generic pemetrexed product for the treatment of cancer, and sought declarations of non-infringement on the basis that the active ingredient in their generic product was pemetrexed diacid, pemetrexed dipotassium or pemetrexed ditromethamine. In 2014, Mr Justice Arnold held that Actavis's products did not infringe the UK, French, Italian or Spanish designations of the Patent, either directly or indirectly (see Actavis UK Ltd v Eli Lilly & Company [2014] EWHC 1511 (Pat)). That decision was partially upheld on appeal by the Court of Appeal, which took the view that there would be indirect infringement, but not direct infringement (see Actavis UK Ltd v Eli Lilly & Company[2015] EWCA Civ 555). The court agreed with the judge's conclusion that the proper construction of the claim did not extend to pemetrexed diacid or any other pemetrexed salts other than disodium because the skilled reader of the patent would not have expected any of Actavis's pemetrexed salts to convert into pemetrexed solution when dissolved in an aqueous solution (Improver v Remington considered) and, on that basis, there could be no direct infringement by Actavis's dealing in the active ingredients of the generic product.


A solution made by dissolving pemetrexed dipotassium in plain water would not infringe because such a solution would contain only potassium ions and pemetrexed ions. However, Actavis's intended implementation was to dissolve and/or dilute each of the active ingredients in saline solution and, therefore, sodium ions would be present. The judge had dealt with this issue by accepting Actavis's submission that "at no point is pemetrexed disodium used in the manufacture of a medicament by anyone". However, as the Court of Appeal explained, the skilled team would have understood from the Patent that pemetrexed disodium was used to refer not only to the solid, but also to solutions containing sodium ions and pemetrexed ions with at least a 2:1 ratio. Further, the language of s 60(2) of the Patents Act 1977 did not require the supply of an element of the claim, but a means relating to an essential element. Consequently, the invention was put into effect when a pharmacist reconstituted or diluted the Actavis products in saline, because there was a stage in the course of that activity when pemetrexed disodium was present and used, which would amount to indirect infringement. Accordingly, the court disagreed with the judge on the issue of contributory infringement. It was common ground that there was no detectable difference in the laws of France, Italy and Spain on the approach to contributory infringement so it followed that the declarations of non-infringement should also be refused in those countries.


Lilly appealed to the Supreme Court on the issue of direct infringement, and Actavis cross-appealed against the rejection of their case that there would be no indirect infringement.




The Supreme Court unanimously allowed Lilly's appeal and dismissed Actavis's cross-appeal. Giving the lead judgment, Lord Neuberger said that as a matter of ordinary language, it was quite clear that the only type of pemetrexed compound to which the Patent's claims expressly extended was pemetrexed disodium. In those circumstances, the Protocol on the Interpretation of Article 69 of the European Patent Convention ("the Protocol") was crucial to Lilly's contention that the scope of protection afforded by the Patent extended to the Actavis products.


Lord Neuberger noted that "the drafting of the Protocol bears all the hallmarks of the product of a compromise agreement" which he said was unsurprising, given the "inevitable conflict between the desirability of giving an inventor an appropriate degree of protection in a particular case and the need for clarity of principle as to the extent of such protection generally". There was also "an unavoidable tension between the appropriateness of giving an inventor a monopoly and the public interest in maximising competition".


More specifically, it was clear from Article 1 of the Protocol that the scope of protection afforded to a patentee was not to be limited by the literal meaning of the claims. However, it was not at all clear how far a court was permitted to move away from the literal meaning. Secondly, it was apparent from Article 2 of the Protocol that there was potentially a difference between interpreting a claim and the extent of the protection afforded by a claim, and, when considering the extent of such protection, equivalents had to be taken into account, but no guidance was given as to precisely what constituted an "equivalent" or how equivalents were to be taken into account. As Lord Neuberger explained, three significant UK cases had considered the question of how far one could go outside the wording of a claim so as to enable the patentee to enjoy protection against products or processes which were not within the ambit of the actual language, construed in accordance with ordinary principles of interpretation.


The domestic case law


The Protocol called for patent claims to be interpreted so as to combine a fair protection for the patentee with a reasonable degree of certainty for third parties. The English courts had achieved that middle ground by applying a purposive construction, as set out in Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183 (even though that case related to a patent granted under the now-obsolete Patents Act 1949 and did not itself involve interpreting the Protocol).


A few years later, the judgment of Lord Diplock in Catnic was reduced to three questions by Hoffmann J (as he then was) in Improver v Remington, as shown in the flowchart below. Thereafter, for the next 15 years or so, this three-stage approach was almost routinely applied by judges in UK patent infringement cases, where the three "Improver questions" were subsequently renamed the three "Protocol questions" (see Wheatley v Drillsafe Ltd [2001] RPC 7 at [23]).




Lord Hoffmann (as he had by then become) addressed the issue again in his speech in Kirin-Amgen Inc v Hoechst Marion Roussel Ltd [2005] RPC 9, where he explained that the "doctrine of equivalents" as developed in the United States courts "allow[ed] the patentee to extend his monopoly beyond his claims" and seemed incompatible with Article 69 EPC 2000, which Lord Hoffmann said "firmly shuts the door on any doctrine which extends protection outside the claims". Lord Hoffmann expressed concern that "once the monopoly had been allowed to escape from the terms of the claims, it is not easy to know where its limits should be drawn". He concluded that, rather than adhering to literalism and adopting the doctrine, the solution was "to adopt a principle of construction which actually gave effect to what the person skilled in the art would have understood the patentee to be claiming", as Lord Diplock had done in Catnic. Furthermore, he said that the principle of purposive construction gave "effect to the requirements of the Protocol" and was "the bedrock of patent construction, universally applicable", whereas the Protocol or Improver questions were simply "guidelines for applying that principle to equivalents ... , more useful in some cases than in others".


The proper approach to infringement claims


In Lord Neuberger's view, the problem of infringement was best approached by considering two issues through the eyes of the person skilled in the relevant art. Those issues were:


  1. does the variant infringe any of the claims as a matter of normal interpretation; and, if not,
  2. 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 was "yes", there was an infringement; otherwise, there was not.


However, Lord Neuberger said, the second issue posed more difficulties of principle: what made a variation "immaterial"? In that connection, Lord Neuberger considered that the three questions in Improver provided helpful assistance, a view supported by the fact that similar but not identical tests have been adopted in other EPC jurisdictions, but that "each of the three questions requires some exegesis, and, particularly the second question, some reformulation". In doing so, Lord Neuberger emphasised, as Lord Hoffmann had done in Kirin-Amgen at [52], that those questions were guidelines, not strict rules (as indeed the Oberlandesgericht indicated in Case No 6 U 3039/16, when saying that it was "generally" true that "three requirements must be met"). Noting that the language of some or all of the questions might sometimes have to be adapted to apply more aptly to the specific facts of a particular case, Lord Neuberger reformulated the three Improver questions as follows:


  1. 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?
  2. 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?
  3. 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?


To establish infringement in a case where there was 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".


Provisional conclusion on direct infringement in the UK


There was no doubt that, according to normal principles of interpreting documents, the Actavis products did not infringe the Patent, as in no sensible way could pemetrexed free acid, pemetrexed ditromethamine, or pemetrexed dipotassium mean (i.e. be said to fall within the expression) "pemetrexed disodium", any more than a slotted rubber rod could be said to be within the expression "a helical metal spring" in the Improver patent.


However, applying the reformulated questions resulted in the conclusion that the Actavis products represented an immaterial variation on the claim and, therefore, infringed the Patent. So far as the first question was concerned, there could be no doubt that those products worked in the same way as the invention: they all ultimately involved a medicament containing the pemetrexed anion and vitamin B12. Thus, they achieved substantially the same result in substantially the same way as the invention. Indeed, as in the Court of Appeal, Actavis realistically accepted that the answer to the first question was "yes".


As to the second question, it seemed clear to Lord Neuberger that the notional addressee of the Patent would appreciate (and would have appreciated as at the priority date) that each of the Actavis products would work in precisely the same way as pemetrexed disodium when included in a medicament with vitamin B12. The reason why he differed from the Court of Appeal and Arnold J on this second question was that, in accordance with the second question as formulated in Improver, they considered that the notional addressee should not be treated as knowing that the Actavis products did in fact work at all, whereas Lord Neuberger said that involved too strict a test.


Turning to the third question, in Lord Neuberger's opinion, the Court of Appeal had adopted an approach which placed too much weight on the words of the claim and not enough weight on Article 2 of the Protocol (although he noted that, in doing so, they were, like Arnold J at first instance, following Lord Hoffmann's guidance in Kirin-Amgen). Such an approach, Lord Neuberger said, made "a nonsense of asking the three questions: if one cannot depart from the language of the claim when considering those questions, what is the point of the questions in the first place?" It seemed to him very unlikely that the notional addressee would have concluded that the patentee could have intended to exclude any pemetrexed salts other than pemetrexed disodium, or indeed pemetrexed free acid, from the scope of protection.


Accordingly, Lord Neuberger concluded that, subject to considering the prosecution history, the Actavis products infringed claim 1 of the Patent.


The effect of the prosecution history


Actavis contended that the prosecution history made it clear that the claims of the Patent should be interpreted as being limited to pemetrexed disodium. However, in Lord Neuberger's judgment, the contents of the prosecution file did not justify departing from the provisional conclusion that the patent had been directly infringed.


Further, Lord Neuberger said that he drew comfort from the fact that neither party was able to refer to a case where a French or Spanish Court had relied upon the patentee's response to a disclosure or added matter objection by the examining officer as being relevant to the scope of claim.


Direct infringement in France, Italy and Spain


Having concluded that the Actavis products directly infringed the Patent as a matter of UK law, Lord Neuberger considered whether the same result would be obtained under French, Italian and Spanish law. In his judgment, direct infringement was established in those jurisdictions as well.


Indirect infringement


Lord Neuberger upheld the Court of Appeal's determination that Actavis were liable to Lilly for indirect infringement in the UK with respect to their products if Actavis knew, or it was obvious in the circumstances, that ultimate users would dilute in saline – or at least Actavis would be liable for indirect infringement if they were not liable for direct infringement. The Court of Appeal said that this conclusion would apply equally to France, Italy, and Spain, and there was no challenge to that from Actavis.


Accordingly, Lilly's appeal was allowed and the court held that the Actavis products infringed the Patent in the United Kingdom, and also in France, Italy and Spain.




This judgment says it is time to "grasp the nettle" of not merely identifying what the words of a claim would mean in their context to the notional addressee, but also considering the extent if any to which the scope of protection afforded by the claim should extend beyond that meaning.


As discussed in the present case, recent UK case law had moved away from any doctrine of equivalents or similar interpretive tool; Lord Hoffmann in Kirin-Amgen was openly sceptical of the doctrine of equivalents in the US and the pith and marrow doctrine in the UK, remarking that both "were born of despair" and that "American patent litigants pay dearly for results which are no more just or predictable than could be achieved by simply reading the claims". After Catnic, the UK courts adopted a principle of construction, which actually gave effect to what the person skilled in the art would have understood the patentee to be claiming. However, with the advent of Article 2 of the Protocol, came the need to take "due account" of any element which was equivalent to an element specified in the claims and the key limitation of the purposive construction theory is that it cannot protect an equivalent or variant that lies beyond the language of the claims. Another drawback of purposive claim construction is that unforeseeable technology arising after the patent is drafted might not be encompassed by the claim, depending on the generality of the language of the claim. Under purposive construction, an unforeseeable (or foreseeable) equivalent that cannot be found within the meaning of the language of the claim cannot infringe, which arguably places too much expectation on drafters of patent claims in the absence of significantly more guidance on patent scope. As Lord Neuberger noted in the present case, it is worth mentioning that Lord Diplock himself in Beecham Group Ltd v Bristol Laboratories Ltd [1978] RPC 153, 200 rejected a submission that "[t]he increasing particularity with which claims are drafted ... has made the doctrine [of pith and marrow] obsolete", but said that the doctrine "still remains a part of patent law".


For questions about this matter or related issues, please contact our Partner Hugh Dunlop (hugh.dunlop@maucherjenkins.com).


Monday, July 31, 2017