In Mylan v Yeda and Teva  EWHC 2629 (Pat) Arnold J has delivered the first substantive High Court judgment to apply the Supreme Court's decision in Actavis v Eli Lilly. Although relatively brief on these points, his treatment of “normal interpretation” and consideration of variants or equivalents makes for interesting reading.
Readers will recall that in Actavis the Supreme Court departed from the previous UK practice of approaching the scope of patent claims by reference to a single issue of interpretation, the latter to be performed using the principles of "purposive construction". This approach was understood to take account of equivalents, as mandated by article 2 of the Protocol to Article 69 EPC, by the use, where appropriate, of the so-called 'Protocol' or 'Improver' questions. In Actavis the Supreme Court held that any consideration of infringement should be approached in two parts, first by considering whether the claim was infringed as a matter of “normal interpretation”; second, by using a modified form of the 'Improver' questions to account for infringement by equivalents. The Supreme Court did not explain in detail how the first issue was to be approached, but cited its own case law on contractual interpretation.
In considering how to apply the Actavis principles, first the judge held at  that the exercise of “normal interpretation” was essentially the same as purposive construction. The judge suggested that the Supreme Court must have meant this, notwithstanding that they used a different phrase. The judge pointed to, in particular, the need to interpret in context (as required under the contractual case law) and the Supreme Court's acknowledgement that the exercise should be undertaken from the perspective of the person skilled in the art.
Second, the judge considered (at [157-167]) whether it was possible for a claim to be anticipated through the second part of the Supreme Court's test, i.e. by an equivalent. This is a crucial issue on which guidance from the courts is urgently required since it has long been understood that a patent's claims must have the same scope for infringement as for validity. Without this balance, a patentee will not be constrained by prior art, to the same degree as previously, in asserting infringement.
The issue arose because of a piece of prior art which disclosed a dosage regime that differed from that claimed, on a normal interpretation of the claim, but which the Claimant asserted was equivalent to the regime claimed.
Whilst observing that the Supreme Court would likely need to resolve this issue, the judge held that the Actavis case has broken the previous symmetry that existed between validity and infringement. This was so notwithstanding that the leading UK authority on anticipation, Synthon, is actually framed in terms of infringement: “the matter relied upon as prior art must disclose subject matter which, if performed, would necessarily result in an infringement of the patent”. Thus it would, perhaps, have been easy for the judge to hold that the Actavis approach to equivalents should be applied to anticipation.
The reasons why the judge did not do this are curious in some respects. The judge referred to the position taken at the European Patent Office in which there is consistent case law from the Technical Boards of Appeal in respect of anticipation by equivalents. The judge quoted at  part of the EPO Case Law book, which includes the following passages: “The case law of the boards of appeal is based on a narrow concept of novelty, i.e. the disclosure of a prior document does not include equivalents of the features which are explicitly or implicitly disclosed; equivalents can only be taken into account when it comes to considering inventive step … According to the case law of the boards of appeal the ‘whole contents’ of an earlier document did not also comprise features which were equivalents of features in the later document ”. With respect to the judge, it might be thought that notwithstanding the EPO case law the judge could have applied Actavis while preserving the symmetry between infringement and validity, not least because of Synthon. The EPO case law is considering one side of the equation only, assessing whether a piece of prior art may be considered to disclose something equivalent to what is expressly claimed. Looking at both sides, one can arguably consider instead whether the claim extends, by equivalence, to something expressly disclosed. The judge held the patent invalid in any event, partly on the basis that the prior art in question rendered the claim obvious. One might therefore view this point as an academic one; however, if the claim scope for infringement is no longer the same as that for validity, there are likely to be other consequences.
We must for present wait to see whether the decision is appealed or for decisions from other judges to see whether Arnold J's views on “normal interpretation” and claim scope for validity will be followed.