Equivalents Unchained
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The Actavis v Eli Lilly decision of the UK Supreme Court has been described by some commentators as being a minor gloss on the law of patent infringement and claim scope. This is, however, to underestimate its implications. The Supreme Court has left open the question of whether claim scope is the same for validity purposes as for infringement and has ensured that UK law now includes a doctrine of equivalents which is unfettered by a parallel doctrine of file history estoppel.
Lord Neuberger fundamentally disagreed with and set aside Lord Hoffmann's 2004 ruling in Kirin Amgen v TKT1 that claim scope was to be decided purely as a matter of construction. In a far-reaching decision, Lord Neuberger has held that patent claim scope is rather a two-part test, only the first of which is claim construction with the second being a new doctrine of equivalents.
The 2004 House of Lords decision in Kirin-Amgen was a pivotal one. Lord Hoffmann held that claim scope should be assessed solely on the basis of a purposive construction. The so-called Protocol Questions, which had been devised as an aid to deciding claim scope, were stated to be useful in many cases but not a substitute for trying to understand what the person skilled in the art would have understood the patentee to mean by the language of the claims. This, he said, was the only compulsory question which was set by Article 69 and its Protocol on Interpretation.
Although in the aftermath of the Kirin-Amgen decision, practitioners did initially complain about being, as Lord Hoffmann predicted they might, "cast adrift on a sea of interpretative uncertainty" the sea did calm down over time. It became clear that ascertaining what a skilled person would understand from the language of the claim was something that could be divined from discussions with suitably qualified technical experts in the art. Consequently, it became possible for practitioners to advise on claim scope, patent infringement and freedom to operate and be on relatively firm ground when so doing. It is safe to say that UK practitioners had become comfortable with applying Kirin-Amgen. Significantly, patent courts in other jurisdictions had also commented favourably upon the test with some even adopting the Protocol questions in their own jurisprudence.
Lord Neuberger's new two-part test for assessing whether an alleged infringing article is within the claim scope involves fully opening the door to equivalents which fell outside the traditional purposive construction of the claim. Lord Neuberger is therefore indicating a radical departure from Lord Hoffmann's earlier decision. The claim scope would extend to obviously immaterial variants which would previously, under the law according to Kirin-Amgen, have fallen outside the claim scope. The sea of interpretative uncertainty has whipped up a storm once again.
Right to depart from Kirin-Amgen Decision?
In the Actavis decision Lord Neuberger states "In the absence of good reason to the contrary, it would be wrong to depart from what was said by the House of Lords [in Kirin-Amgen]"2. The context of this comment is within a discussion of the reliance which could be placed on the contents of the patent office file. But the irony is that Lord Neuberger's comment might have been applied more generally in the Actavis case.
Under the common law rules of precedent, the Supreme Court's previous decisions are normally binding on itself and may only be departed from "where it appears right to do so"3,. This has generally been interpreted to cover only those cases where the previous decision is wrong or where it has caused injustice or uncertainty or where it has hindered the development of the law. In light of this, the Supreme Court has generally been quite reluctant to depart from its own previous decisions. In a 1982 case4 it was held that, before departing from its own decision, the House of Lords should be sure that continued adherence to precedent involved the risk of injustice and departure should facilitate the safe and appropriate way of remedying that injustice. In a 2016 decision5 it was stated that "at a time when the cost of litigating can be very substantial, certainty and consistency are very precious commodities in the law". The Supreme Court held that it was well established that the Court should not refuse to follow an earlier decision merely because they would have decided it differently but there had, in the instant case, been a material change in the relevant legal landscape since the earlier decisions which now gave rise to an overwhelming case for changing the law.
If the Kirin-Amgen case had produced injustices or hindered the development of the law in the 13 years since its handing down, one might have expected there to have been a vocal lobby calling for its overturn. It is unfortunate that the Supreme Court saw fit to depart from such a long-standing tenet of patent law as purposive construction without a detailed analysis of the rationale for such departure.
Return of the Angora Cat?
One of the other key tenets of UK patent law is "that the construction of a claim is the same whether validity or infringement is to be considered; no patentee is entitled to the luxury of an “elastic” claim which has a narrow meaning in the former case but a wide meaning in the latter6.
In the Supreme Court it is fair to say that the impact upon the validity of the patent claim of an extremely generous scope which encompassed equivalents, received minimal examination. The court appears to have proceeded on the basis of a fallacy; that a patentee always wants the broadest scope of protection possible. However, in the process of claim formulation and refinement, during the dialogue with the patent office, the patentee actually has a number of competing considerations in mind. These include formulating the claim so that it is new and inventive, (i.e., avoids the prior art), ensuring that it is sufficient, (i.e., properly enabled), ensuring that the patent gives practical protection against likely infringements and perhaps most importantly, formulating the claim so that it is formally acceptable to the examining authority.
These various factors are ever-present in the minds of patentees, patent attorneys, litigators and others steeped in the vagaries of patent law. Practical considerations inevitably come into play: a patentee may know that a certain form of claim would be immediately acceptable to the office and so be granted quickly, while another, broader form might be granted but only more slowly and after some resistance. If there is a practical need to begin infringement proceedings, patentees often opt for the narrower claim in such circumstances. It is…
