Introduction

In its decision of July 12, 2017 in Actavis v. Eli Lilly, the Supreme Court of the United Kingdom for the first time formally adopted the concept of a doctrine of equivalents when considering what constituted an infringement under UK patent law.

The patent in question arose from a European Patent application which had been validated in several European countries. The action had commenced when Actavis sought judgment that its proposed sales did not infringe the UK, German, French, Italian or Spanish patents arising from that European application. The Supreme Court found that its judgment applied not only to the UK patent, but also to those in France, Italy and Spain.  The court did not consider the German patent in view of a separate action in Germany.

The court concluded that Actavis’ sales of pemetrexed compounds for use in conjunction with vitamin B12 infringed an Eli Lilly patent covering its product Alimta and claiming pemetrexed sodium in the manufacture of a medicament for use in combination with Vitamin B12 for treatment of cancer. Vitamin B12 is used in conjunction with pemetrexed sodium to reduce side effects.

Background

Long ago, English law recognized that a patent could be infringed by acts falling outside the scope of the claim if the infringer took what was referred to as the “pith and marrow” of the invention. As the nineteenth century wore on and legal philosophy moved in the direction of thinking that, at least in matters of economic law, it was more important to have precision than absolute fairness, the doctrine of pith and marrow became disfavored. Instead, UK courts adopted the view that if something did not fall within the four corners of the patent claim, it was not an infringement. Considerations of whether the alleged infringer used the same inventive concept that underlay the patent could be left to the Germans and their attempts to determine what was or was not use of an allgemeine Erfindungsgedanke (general inventive concept). This is not to say, however, that English courts were always absolutely literal in their interpretation of patent claims.  Some flexibility might be allowed occasionally, for example in Barking Brassware Co. Ltd v. Allied Ironfounders (1962), a claim requirement that elements should be “coaxial” was found to be met by an infringement in which one element was encompassed by another even though the axes were not identically located and in Catnic Components Ltd. V. Hill & Smith Ltd (1982), a claim requirement that something was “vertical” was found to be met by a support that was 6 degrees off the vertical. The House of Lords reached the latter decision by holding that patent claims should be construed in a “purposive” manner so that if it was clear that the draftsman was using a term in a general sense rather than in its strict meaning, the former construction should be applied when considering infringement. The situation became confused, however, when Justice Hoffman attempted to use this concept of “purposive construction” more broadly in the case of Improver Corporation v Remington Consumer Product Limited (1989) and set out the following considerations when deciding whether a variant falling outside the narrow meaning of a claim might nevertheless be an infringement:

1. Did the variant have a material effect upon the way the invention worked? If it did, then there was no infringement.
2. If the variant had no material effect upon the way the invention worked, would that have been obvious to the skilled addressee? If not, then there was no infringement.
3. Assuming an affirmative result under (1) and (2), did the specification make it obvious to the skilled addressee that the variant could not have been intended to be excluded from the ambit of the claim? If so, there would have been no infringement.

These came to be known as the “Improver questions” and were the standard test for determining infringement until their author, now in the House of Lords, reconsidered the issue in 2004 in Kirin-Amgen v Hoechst Marion Roussel. In that case, Lord Hoffman reiterated the importance of using a purposive construction to patent claims but characterized the Improver questions as guidelines rather than black letter law.

In the meantime, however, there had been a change in the applicable legislative framework.

The European Patent Convention was signed in 1973 and came into force in 1978. The UK Patent Act states that it is intended to have the same effect as the corresponding provisions of the European Patent Convention. The European Convention includes a Protocol on the scope of patent protection in Article 69, 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.

Article 69 is interpreted as defining a position which combines a fair protection for the patent proprietor with a reasonable degree of legal certainty for third parties.  English courts had found that both the purposive construction approach to interpretation of patent claims and use of the Improver questions complied with this requirement.

However, the Protocol was amended in 2001 to add a further provision to the Protocol which reads as follows:

• 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.

This amendment came into effect on December 13, 2007.

The Decision on What Constitutes Infringement Under English Law

As noted above, the patent claims in Actavis v. Eli Lilly specifically required use of the sodium salt of pemetrexed. The product in respect of which a declaration of non-infringement was sought used either the free acid or a different (ie, potassium) salt. Questions arose as to whether this constituted direct infringement under the purposive construction doctrine, the Improver questions or some other test and whether sale of the compounds for use in a saline solution where it was claimed the sodium salt would be formed would constitute indirect infringement.

At first instance, it was held that there was no direct or indirect infringement.

The English Court of Appeal found that there would be no direct infringement, but that there would be contributory (indirect) infringement.

In a judgment by Lord Neuberger (who had earlier in his career sat as a judge in the Patents Court), the Supreme Court unanimously held that Actavis’ activities would constitute direct infringement and that, had it been necessary to reach a decision on the point, it would also have found there to be indirect infringement as well.

Direct Infringement

After reviewing the history of English law on the question of non-literal infringement of patent claims discussed above and the law in other countries that are bound by the European Patent Convention and its Protocol, Lord Neuberger concluded that previous attempts to elide the questions of claim interpretation and what constituted an infringement had been mistaken.  He considered this to be the case, particularly in view of the amendment to the Protocol on Article 69 of the European Patent Convention. He further considered that the two issues should be addressed separately: First, the claim should be construed according to the normal principles of construction; and then, it should be determined whether an alleged infringement fell within either the normal meaning of the claim or was an equivalent thereof.

After noting that variation in the language might be necessary to accommodate specific circumstances, the opinion set out the following test to be used to determine what was an equivalent:

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?

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 went on to consider whether the prosecution history of the patent application should have any effect on a determination of infringement when applying this test. He concluded:

• In my judgment, it is appropriate for the UK courts to adopt a skeptical, 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 … 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 …. However, given that the contents of the file are publicly available … there will be occasions when justice may fairly be said to require reference to be made to the contents of the file. However…, 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.

In the present case, there was no need to do so.

Indirect Infringement

Lord Neuberger commented that, had it been necessary, he would have upheld the Court of Appeal’s determination that Actavis was liable to Lilly for indirect infringement in the United Kingdom with respect to its products if Actavis knew, or it is obvious under the circumstances, that ultimate users will dilute the products being sold in saline, which would result in formation of an aqueous solution of the sodium salt of pemetrexed.

Extraterritorial Applicability

As noted above, this finding of infringement was made not only with respect to the UK patent but also the corresponding French, Italian and Spanish patents.  The basis for this extraterritorial applicability is that since validity of the patent was not an issue in the context of a declaration of non-infringement, following the Supreme Court’s decision in Lucas Film Ltd v. Ainsworth,  the question of infringement of different patents having the same text in other countries with the same basic law was justiciable in the English courts. Before reaching this conclusion, the UK Supreme Court did consider expert testimony on the question of patent infringement in other European countries. Based on this testimony, it concluded:

• French law applies the doctrine of equivalents where the variant is “different in form but perform[s] the same function” as the invention, but only where “the function [claimed in the patent] is a new one”.
• Under Italian law, a variant would be held to infringe if (i) it reproduced the “inventive core” of the patent and (ii) it was an obvious variation, although (iii) the fact that the variant included some modifications which were not obvious and/or the fact that the variant does not include some of the elements of the patent claim does not necessarily prevent the variant from infringing.
• Spanish courts appear to have effectively adopted the approach embodied in the three questions suggested by Justice Hoffmann in Improver.

Based on these conclusions, Lord Neuberger was comfortable in holding that there was infringement in these countries as well as in the United Kingdom.