Actavis v Eli Lilly: The Impact On Patent Infringement Law In The UK Two Years On

It is now two years since the UK Supreme Court's judgment in Actavis v Eli Lilly [2017] UKSC 48 (12 July 2017) re-steered in a markedly different direction the law of patent infringement in the UK, stating that there is a doctrine of equivalents. How has English patent law developed its doctrine of equivalents since then, and how has the Supreme Court's judgment impacted other aspects of patent law? We thought this was a good moment to reflect on the activity in the courts since the ground-breaking judgment of 2017.

Background: what the UK Supreme Court said in Actavis v Eli Lilly and the questions arising

In Actavis v Eli Lilly, Lord Neuberger said ([54]):

"...a problem of 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 in suit, ie the person skilled in the relevant art. Those issues are: (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."

This gave rise to a two-limbed approach to the assessment of infringement in the UK, a departure from decades of practice under the "purposive approach", as explained in our 2017 article "UK Supreme Court introduces doctrine of equivalents in patent law in Actavis v Lilly".

The Supreme Court's judgment in Actavis v Eli Lilly, however, gave rise to a number of questions; both on the detail of the new approach to infringement and the implications of the ruling for other aspects of patent law. In the course of the last two years, the English courts have been grappling with these questions, as a result of which patent law in the UK has become better developed and settled.

Patent infringement under the "normal interpretation" (limb (i))

Immediately following the Supreme Court's judgment in Actavis v Lilly, questions arose as to what, exactly, was meant by infringement "as a matter of normal interpretation". How much of the former purposive approach remained intact?

Under the purposive approach (as laid down in Catnic [1982] RPC 183, Improver [1990] FSR 181 and Kirin-Amgen [2005] RPC 9), the reach of a patent claim for the purposes of assessing infringement was defined by giving effect to "what the skilled person in the art would have understood the patentee to be claiming". This was an objective interpretation of the language of the claim, through the eyes of the skilled addressee (who brought with them their common general knowledge) in light of the description and drawings of the patent. The purposive approach was a contextual interpretation, intended to be contrasted with "old English literalism" which had characterised the approach to the interpretation of commercial documents under English law until the 1970s. Such old English literalism did not permit consideration of the contextual background to the making of a commercial document when considering its objective interpretation, and so in that sense could be described as acontextual.1 The purposive approach was also to be contrasted with assigning meaning to claim language according only to the conventional rules for the use of language, such as one finds in a dictionary or the rules of grammar.2 In the interpretation of patent claims under the purposive approach, the employment of the person skilled in the art, imbued with their common general knowledge, imported contextuality, along with the necessary consideration of the description and drawings of the patent specification. Claim language could not be ignored if it did not appear to make any difference to the inventive concept.3

Further, under the purposive approach, it was permissible, when construing the claim language, to have regard to the alleged infringing product or process. The court could consider a series of questions (the Improver or "Protocol" questions) to assist in deciding whether the alleged infringing product or process fell within or outside the claim, albeit that the House of Lords had discouraged their use in Kirin-Amgen and they had seen less employment in patent judgments in the years preceding Actavis v Eli Lilly. Lord Neuberger said that this aspect of the purposive approach conflated the issues, was wrong in principle and therefore could lead to error. But Lord Neuberger did not expressly state how much of the purposive approach he intended to undo. In particular, did the principles described in the previous paragraph remain intact?

Two years on, the following can be said:

The former Improver/Protocol questions form no part of the assessment of the normal interpretation of the claim (Icescape v Ice-World [2018] EWCA Civ 2219 (Kitchin and Floyd LLJ), Regen v Estar [2019] EWHC 63 (HHJ Hacon); notable earlier commentary in Liqwd v L'Oréal [2018] EWHC 1394 (Birss J)). The "normal interpretation" is a purposive interpretation because it is the ascertaining of the objective meaning of the words of the claim in their context to the skilled addressee (Icescape v Ice-World [2018] EWCA Civ 2219 (Kitchin & Floyd LLJ), Regen v Estar [2019] EWHC 63 (HHJ Hacon); notable earlier commentary in Generics v Yeda [2017] EWHC 2629, Actavis v ICOS [2017] EWCA Civ 1671 (Kitchin LJ), Illumina v Premaitha [2017] EWHC 2930 and Liqwd v L'Oréal [2018] EWHC 1394). In other words, "normal interpretation" is the pre-Actavis v Eli Lilly purposive approach but without the Improver/Protocol questions. Accordingly, the principles of construction originally set out in Kirin-Amgen, then elaborated on by the Court of Appeal in Virgin v Premium [2009] EWCA Civ 1062 at 5 remain good law in respect of normal interpretation (Saab v Seaeye [2017] EWCA Civ 2175 at [19]). This now represents the minimum protection afforded by the patent (Icescape v Ice-World [2018] EWCA Civ 2219).

Patent infringement under the doctrine of equivalents (limb (ii))

The resolution of a question of infringement under the normal interpretation (Lord Neuberger's limb (i)) will only conclude the issue of infringement between the parties if a finding of infringement is reached under that limb (or if the patentee does not assert the doctrine of equivalents). If infringement is not established according to the normal interpretation, then following Actavis v Eli Lilly, the court will consider whether there is nevertheless infringement under the doctrine of equivalents (Lord Neuberger's limb (ii)).

In Actavis v Eli Lilly, Lord Neuberger described limb (ii) as addressing the following issue: "does the variant nonetheless infringe because it varies from the invention in a way or ways which is or are immaterial?"

In this context Lord Neuberger considered that the Improver/Protocol questions provided helpful assistance but needed some reformulation. He proceeded to undertake the reformulation, emphasising that the 'reformulated questions' remained only guidelines, not strict rules, and that they might sometimes have to be adapted to apply more aptly to the specific facts of a particular case. In Icescape v Ice-World, the Court of Appeal (Kitchin LJ) subtly re-stated the limb (ii) approach.

First, without acknowledging Lord Neuberger's comments about the reformulated questions being guidelines, not strict rules, and sometimes needing adaption, Kitchin LJ said that the limb (ii) question "is to be determined by asking these three questions".

By making this statement, Lord Kitchin indicated that the reformulated questions should be considered the mandatory approach to the assessment of limb (ii), moving the emphasis away from Lord Neuberger's phrasing "does the variant nonetheless infringe because it varies from the invention in a way or ways which is or are immaterial". While this is unlikely to make a difference in most cases, in the occasional case it will be worth remembering that there is a conceptual difference and Lord Neuberger's approach potentially permits more flexibility in the assessment of limb (ii). Lord Neuberger's judgment remains the authority on the point. Nevertheless Lord Kitchin is now the intellectual property specialist in the Supreme Court, so he may embody his elaboration at some future date.

Turning to the reformulated questions, Kitchin LJ's modification (shown in bold text below) of Lord Neuberger's language results in the following:

Notwithstanding that it is not within the literal (that is to say, I interpolate, normal) 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? 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? 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".

Kitchin LJ's interpolation of "normal" for "literal" in the first of the reformulated questions would introduce a change if Lord Neuberger had meant an acontextual (i.e. the dictionary meaning) literal construction of the wording in the claims. If this was the correct interpretation of Lord Neuberger's judgment, then the analysis of limb (ii) would involve first stepping back from the normal interpretation of the claim language to a stricter, less contextual one (if different), before then considering the issue of equivalents...