An improved Improver? UK Supreme Court moves towards a UK Doctrine of Equivalents in Lilly pemetrexed battle

It is here - the Supreme Court's decision in Eli Lilly v Actavis UK [2017] UKSC 48.  This is an important case about whether drugs manufactured by Actavis infringe a European patent of Lilly. The product in question is pemetrexed

which is an anti-cancer drug, damaging side-effects of which can be mitigated if it is given together with vitamin B12. The case reviews some fundamental aspects of patent law as applied in the UK and Europe including with regard to "equivalents", and the scope and applicability of "purposive construction" and the so-called Improver questions.

Eli Lilly has been marketing pemetrexed with vitamin B12,
 under the brand name Alimta, since 2004

The patent claims the use of the disodium salt of pemetrexed in the manufacture of a medicament for use in combination with vitamin B12 for the treatment of cancer. The dispute between the parties which came before the Supreme Court boiled down to whether a medicine containing a different salt of pemetrexed would infringe the patent, either directly or indirectly. The Patents Court (Arnold J. [2015] RPC 6) had decided that none of the Actavis products would directly or indirectly infringe the patent. The Court of Appeal ([2015] EWCA Civ 555 and 556) allowed Lilly’s appeal in part holding that there would be indirect infringement, but not direct infringement. Lilly therefore appealed to the Supreme Court on the issue of direct infringement, and Actavis cross-appealed on indirect infringement.

  

Last week on 7 July the Supreme Court announced that it had allowed Eli Lilly’s appeal and held that Actavis’s products directly infringe Eli Lilly’s patent, as previously reported in IPKat. Today the court handed down its reasons for those conclusions, the unanimous decision being given by its President, Lord Neuberger, and the other Supreme Court justices, Lords Mance, Clarke, Sumption and Hodge, agreeing with it. The case deals with some important issues relating to patent infringement - including how alleged “equivalents” should be dealt with, whether the prosecution history of a patent should be used when interpreting its claims, and the scope of the concept of contributory or indirect infringement.

The court summarised the issues on direct infringement like this. Lilly said that the Actavis products infringe the Patent because they consist of a pemetrexed salt or the free acid with vitamin B12, which represents the essence of the teaching and claim of the Patent. Actavis said that they don't infringe because Lilly's claims are limited to a specific pemetrexed salt, pemetrexed disodium, and the Actavis products contain either the free acid or different pemetrexed salts such as the dipotassium salt.

Lord Neuberger

In construing the claim, the court was satisfied that "as a matter of ordinary language" the claims only extended to the disodium salt; but that was not the end of the story. The Protocol on the Interpretation of Article 69 as amended in EPC 2000 had to be factored in. The definition of infringement in section 60(1) of the Patents Act 1977 is, according to section 130(7) of the same Act, deemed to be “so framed as to have, as nearly as practicable, the same effects in the United Kingdom as the corresponding provisions of the European Patent Convention ...". Accordingly, the court had to look at the matter by reference to the EPC, including the effect of its amendment by EPC 2000. The relevant bit of the Protocol to Art. 69 is the new Art. 2 added by EPC 2000 which says "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." That led the court to a consideration of prior English case law as well of that of other EPC member states. In doing so it acknowledged that the addition of Art. 2 had all the hallmarks of a compromise about it, and that “complete consistency of approach” between different national courts of the EPC states “is not a feasible or realistic possibility at the moment”, but nonetheless “it is sensible for national courts at least to learn from each other and to seek to move towards, rather than away from, each other’s approaches”, quoting from its own judgment in Schütz v Werit [2013] RPC 16.

In particular the court considered the evolution of the approach to equivalents in the UK, based on "purposive construction" of the claims, starting from from the decision of Lord Diplock in Catnic v Hill & Smith [1982] RPC 183 and moving through the questions originally posed by Lord Hoffmann in Improver v Remington [1990] FSR 181 which became known as the "Improver" or "Protocol" questions. Later, in Kirin-Amgen v Hoechst Marion Roussel [2005] RPC 9 Lord Hoffmann confirmed that purposive construction as in Catnic and Improver 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”.

Having gone through the case law in the UK and other EPC countries in some detail, the court went on to explain its own view, based on recognising that any patent system must strike a balance between the two competing factors referred to at the end of Article 1 of the Protocol, namely “a fair protection for the patent proprietor [and] a reasonable degree of legal certainty for third parties”. On that basis the court said that infringement is best approached by addressing two issues, each of which is to be considered through the eyes of the notional addressee of the patent, who is the person skilled in the 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. The court said that this approach complies with article 2 of the Protocol, as issue (ii) "squarely raises the principle of equivalents, but limits its ambit to those variants which contain immaterial variations from the invention". Considered in that way, the court considered that question (i) raises a question of interpretation, whereas question (ii) would normally have to be answered by reference to the facts and expert evidence. The court then criticised Lord Hoffmann's "conflating" of these two issues in Kirin-Amgen as "wrong in principle".

In the court's view, issue (ii) involves not merely identifying what the words of a claim mean, but whether the the scope of protection should extend beyond that meaning - quoting Sir Hugh Laddie in "Kirin-Amgen - The End of Equivalents in England?" (2009) 40 IIC 3, para 68, “[t]he Protocol is not concerned with the rules of construction of claims” but with “determining the scope of protection”.

Applying question (i), there was no doubt that the Actavis products do not infringe, because the free acid or other salts of pemetrexed do not to fall within the expression, “pemetrexed disodium” in claim 1 of the Patent, any more than a slotted rubber rod could be said to be within the expression “a helical metal spring” in the claim in the Improver patent. According to normal principles of interpreting documents, then, this would be the end of the matter.

In looking at question (ii) the court thought that the Improver questions could still provide helpful assistance, but the questions might require some reformulation. The court then proceeded to go over the Improver questions in ways which seem to this GuestKat rather reminiscent of a tutor marking an exam paper. The first Improver question was marked as "generally satisfactory". That question is posed like this:

(1) Does the variant have a material effect upon the way the invention works? If yes, the variant is outside the claim.

The second question however required some improvement. This question is only asked if the answer to question (1) is "no", i.e. the variant doesn't have a material effect. It was originally formulated like this:

(2) Would this (ie that the variant had no material effect) have been obvious at the date of publication of the patent to a reader skilled in the art?

In the court's view this question "imposes too high a burden on the patentee ... given that it requires the addressee to figure out for himself whether the variant would work". In the court's opinion, the second question would be better expressed "as asking whether, on being told what the variant does, the notional addressee would consider it obvious that it achieved substantially the same result in substantially the same way as the invention." Thus the second question should be asked "on the assumption that the notional addressee knows that the variant works to the extent that it actually does work."

The third Improver question was marked as "an acceptable test, provided that it is properly applied". This question is only asked if the answer to the second question is "yes", i.e. it would have been obvious that the variant had no material effect. The third question goes like this:

(3) Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention?

If the answer to that question "yes", the variant is outside the claim, and there is no infringement.

In relation to its comment about the need for question 3 to be "properly applied" the court made four points which it is worth setting out in full in order to try to grasp some of the subtleties of approach:

"First, although “the language of the claim” is important, consideration of the third question certainly does not exclude the specification of the patent and all the knowledge and expertise which the notional addressee is assumed to have. Secondly, the fact that the language of the claim does not on any sensible reading cover the variant is certainly not enough to justify holding that the patentee does not satisfy the third question. Hence, the fact that the rubber rod in Improver [1990] FSR 181 could not possibly be said to be “an approximation to a helical spring” ... was not the end of the infringement issue even in Hoffmann J’s view: ... it was because the rubber rod could not possibly be said to be a helical spring that the allegedly infringing product was a variant and the patentee needed to invoke the three Improver questions. Thirdly, when considering the third question, it is appropriate to ask whether the component at issue is an “essential” part of the invention, but that is not the same thing as asking if it is an “essential” part of the overall product or process of which the inventive concept is part. So, in Improver [1990] FSR 181, 197, Hoffmann J "may have been" ... wrong to reject the notion that “the spring could be regarded as an ‘inessential’”: while it was undoubtedly essential to the functioning of the “Epilady”, the correct question was whether the spring would have been regarded by the addressee as essential to the inventive concept, or inventive core, of the patent in suit. Fourthly, when one is considering a variant which would have been obvious at the date of infringement rather than at the priority date, it is ... necessary to imbue the notional addressee with rather more information than he might have had at the priority date."

In the circumstances, noting the weight that has been given by courts in the UK (and in some other jurisdictions) to the Improver questions, the court thought it right to express, in its own words, a reformulated version of those questions, whilst still emphasising, as Lord Hoffmann had said, that these questions are guidelines, not strict rules. The court's three reformulated questions are as follows:

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, ie 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”. In this case the court was satisfied that the application of the three questions results in the conclusion that the Actavis products infringe. They achieve substantially the same result in substantially the same way as the invention. As to the second question, the notional addressee of the patent would appreciate that each of the Actavis products would work in precisely the same way as pemetrexed disodium when included in a medicament with vitamin B12. Investigating whether the free acid or other salts would work would be a "purely routine exercise". The court explained the difference in its view from that of the Court of Appeal and Arnold J. on the second Improver question by saying that, in relation to that second question, the lower courts had considered that the notional addressee should not be treated as knowing that the Actavis products did in fact work at all, whereas, as explained above, that seemed to the court to involve too strict a test.

On the third question, the Supreme Court thought that the Court of Appeal had adopted an approach which put too much weight on the words of the claim and not enough weight on article 2 of the Protocol. In doing so, the Supreme Court acknowledged that they, and Arnold J. at first instance, were following Lord Hoffmann’s guidance in Kirin-Amgen. Thus Floyd LJ. in the Court of Appeal thought that there was “no obvious leeway as a matter of language for giving [the claim] a broad as opposed to a narrow construction”. The Supreme Court saw that as a product of treating the issue raised by the third question as being one of normal interpretation, or, in the language of Sir Hugh Laddie, wrongly conflating the issue of interpretation with the issue of scope of protection. To take this approach, such that no departure from the language of the claim was permitted, would remove the point of asking the questions in the first place.

Thus, the Court of Appeal considered that the notional addressee “would understand that the patent was clearly limited to the disodium salt, and did not extend to the diacid or the dipotassium or ditromethamine salts”. In the view of the Supreme Court, the addressee of the Patent would understand that the reason why the claims were limited to the disodium salt was because that was the only pemetrexed salt on which the experiments described in the specification had been carried out. But it did not follow that the patentee did not intend any other pemetrexed salts to infringe. The court said that would confuse the disclosure of the specification of a patent with the scope of protection afforded by its claims. The court thought it 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. Therefore the Court concluded that, subject to considering the prosecution history, the Actavis products would infringe claim 1 of the Patent.

This GuestKat finds that conclusion a little surprising and is still digesting it. In view of the length already of this post, there will be a part 2 dealing with prosecution history and indirect infringement, and any other comments. At the moment, a pause for breath seems appropriate, before reaching any conclusions as to the effect of what seems to be a significant reboot of the approach to patent infringement in the UK courts.