Patents: claim interpretation

By Audrey Horton



The High Court has held that a patent for treatment of multiple sclerosis was invalid for obviousness, and considered the impact on claim interpretation of a recent restatement of the law by the Supreme Court.


The scope of patent claims is determined in accordance with Article 69 of the European Patent Convention and the Protocol on the Interpretation of Article 6, which aim to provide a balance between fairness to the patentee and giving the public a reasonable degree of certainty as to what those claims cover. 

In Actavis UK Ltd and others v Eli Lilly, the Supreme Court held that a claim could be infringed under a doctrine of equivalents even though the allegedly infringing act did not fall within the claim on its proper interpretation ( Validity was not considered in Actavis

Before Actavis, the House of Lords held that when interpreting patent claims, the key question was what the person skilled in the art would have understood the patentee to have used the language of the claim to mean (Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183 (HL) and Kirin-Amgen Inc v Hoechst Marion Roussell [2004] UKHL 46). This involved giving the claim a purposive construction: interpreting it having regard to the fact that the patentee's purpose was to describe and claim an invention.

Before Actavis, it was settled law that patent claims ought to be interpreted in the same manner, and had the same scope, for the purposes of considering both novelty and infringement. In Synthon BV v SmithKline Beecham plc, the House of Lords held that two requirements were necessary to establish that a claim lacked novelty over a prior publication (whether written, oral or by use), the prior publication must: 

  • Disclose subject matter which, if performed, would necessarily result in an infringement of the patent (prior disclosure). 
  • Enable the skilled person to perform the claimed invention using his common general knowledge (enablement) (

In Arrow Generics Ltd v Merck & Co Inc, the High Court held that it had a discretionary power to grant a declaration (an Arrow declaration) that a generic pharmaceutical was obvious at the priority date of divisional patent ([2007] EWHC 1900 (Pat)). This was confirmed by the Court of Appeal in Fujifilm Kyowa Kirin Biologics Co, Ltd v AbbVie Biotechnology Ltd & Another [2017].


S and M applied to revoke a patent owned by Y and exclusively licensed to T on the grounds of lack of novelty, lack of inventive step and insufficiency. They also sought an Arrow declaration. Y and T counterclaimed for threatened infringement of the patent.


The court held that the patent was invalid for being obvious in relation to one item of cited prior art. 

In Actavis, the Supreme Court departed from Catnic and Kirin-Amgen with respect to the correct approach to equivalents to elements specified in the claims for the purposes of determining the scope of protection of patents in the context of infringement. The question was whether, in the light of this new law, patent claims ought still to be given a purposive construction. 

The court considered that, before coming to any question of equivalents, it remained the law that patent claims should be given a purposive construction. Patents differed from commercial contracts in two ways. A contract was a bilateral statement agreed between contracting parties, whereas a patent was a unilateral statement made by the patentee and addressed to the person skilled in the art. A contract contained promises by the contracting parties to each other; a patent described and claimed an invention for the purpose of creating a legal monopoly. Patents must be interpreted through the eyes of the person skilled in the art, interpreting the words of the claim in context. The context had to include the very purpose for which the document existed, namely to describe and claim an invention.

Another question which arose in the light of Actavis was what effect, if any, the finding that a claim could be infringed under a doctrine of equivalents, even though the allegedly infringing act did not fall within the claim on its proper interpretation, had on the law of novelty. The question was whether it remained the law that a claim lacked novelty if the prior publication disclosed subject-matter which, if performed, would necessarily infringe the claim. The court's view was that the claim would only lack novelty if the prior publication disclosed subject-matter which fell within the claim on its proper interpretation. It was not sufficient for lack of novelty that the subject-matter would infringe the claim applying the doctrine of equivalents. 

The claims as interpreted were not anticipated by the cited prior art, but were obvious. The court noted that if, contrary to its view, the law was that a claim lacked novelty if the prior publication disclosed subject-matter which if performed would necessarily infringe under the doctrine of equivalents, then the claims would not have been novel over the prior art.  As this issue was not addressed in Actavis it would require another Supreme Court decision.

The existence of pending divisional applications was a necessary but not sufficient basis to justify the making of an Arrow declaration. Y and T had not sought to shield the subject-matter of the patent from scrutiny by the courts and had vigorously defended the validity of the patent at trial. An Arrow declaration would not provide S and M with greater certainty than a reasoned judgment. In the circumstances S and M were not entitled to an Arrow declaration.


This is the first High Court case to consider the effect of the controversial Supreme Court decision in Actavis. The court did not accept that the Supreme Court intended to abolish the long-established approach to claim interpretation, purposive construction. On the other hand, the court noted, obiter, that the previous symmetry between validity and infringement that existed before Actavis had changed so that the doctrine of equivalents did not apply to the part of the novelty test that requires consideration of whether the prior art if performed would necessarily result in infringement. As this decision is likely to be appealed, it will be interesting to see how the Court of Appeal will apply Actavis.

Case: Generics (UK) Ltd (t/a Mylan) and another v Yeda Research and Development Company Ltd and another [2017] EWHC 2629 (Pat).

First published in the December 2017 issue of PLC Magazine and reproduced with the kind permission of the publishers.  Subscription enquiries 020 7202 1200.