05 March 2019 | Audrey Horton Professional Support Lawyer

The High Court has held that a patent was invalid as anticipated by a prior disclosure by the patent owner and obvious over an item of cited prior art.


In Actavis, the Supreme Court considered the scope of protection of a patent claim when assessing infringement, and reformulated the law (the Improver questions) relating to infringement by immaterial variants ([2017] UKSC 48).

In Improver v Remington, the High Court set out a three-step test for determining whether variation from the exact claim language falls within the scope of the claim (the Improver questions) ([1989] 5 WLUK 162).


R owns a European patent claiming a method for the preparation of platelet rich blood plasma.

R sued E for patent infringement by the supply of kits in the UK used to prepare plasma according to the method claimed in the patent. E counterclaimed for revocation of the patent on the grounds of lack of novelty, lack of inventive step and insufficiency.

R made a conditional application to amend the patent, which E opposed. After the trial, E applied to reopen the trial on the basis of the discovery of new evidence.


The court held that the patent, even if amended, was anticipated by a prior disclosure and was obvious over one item of prior art, but was not insufficient. If valid, the patent as construed in line with Actavis would be infringed by equivalence.

The court refused E's application to introduce new evidence. It held that the outcome of a further hearing on prior use could make no difference to the outcome of the trial as a whole.

In determining invalidity for anticipation or obviousness, the state of the art consists of items of information. The skilled person did not understand this in isolation but in the light of their collective common general knowledge. In the UK, common general knowledge was territorial in scope, requiring sufficient dissemination in the UK. The court noted that the common general knowledge contemplated by the European Patent Office was, in principle, different to the common general knowledge of the skilled person in each European Patent Convention state. The attributes of the skilled person in national proceedings, including territorial issues, were determined by national courts. Adoption of a similar approach would be desirable, but there had been no discussion of this by non-UK courts.

In principle, the law relating to combining documents for the purpose of obviousness was no different in the context of a website. A website might not invariably be treated as a single document. If a single page was cited as prior art, it did not follow that the skilled person could be taken to have read every part of the website from which it came.

Also, an argument based on the combined teaching of two or more pages from a website could not ignore other pages that the skilled person would have read. There should be no inappropriate selection. Assuming the evidence established that the skilled person's browsing would have extended widely, all the browsed website pages must be taken into account, including those containing inconvenient details of the kind found in documentary disclosures, such as misleading directions or distracting context.

Three issues relating to infringement by equivalence were raised:

The first was whether multiple differences between the alleged infringement and the claim on a normal construction should be assessed separately, or whether the correct assessment is in relation to a single variant product or process with all differences taken together Only the latter result was relevant. The question was whether the accused product or process was a variant falling within the scope of the claim taking all equivalents into account. It would often be convenient to consider equivalents one by one, but there had to be a single overall answer in relation to each accused product or process.

Secondly, it was incorrect that Actavis meant the doctrine of equivalence could not apply to a numerical limit in a claim. The approach to claims containing one or more numerical limits (numerical claims) was no different from that applicable to any other claim and Actavis had not changed that. The reasons for reaching the conclusion that, on the normal construction of a numerical claim, the accused product or process fell outside the claim, did not necessarily drive the skilled person to the view that the patentee intended that strict compliance with the relevant numerals was an essential requirement of the inventive concept. If this were so it would put numerical claims into a special class to which the doctrine of equivalence did not apply. Also, the normal construction of a claim might be narrower than the purposive construction according to the previous law, so the effect of Actavis could be to narrow the scope of numerical claims, contrary to the Supreme Court's intention. In principle it was possible to conclude that as a matter of normal construction a numerical limit could not be stretched to cover the accused product or process, but that the variant had a numerical value sufficiently equivalent to that defined in the claim such that the variant fell within its scope.

Thirdly, according to previous law, an integer could not be disregarded if it did not appear to make any difference to the inventive concept. The revisions to the Improver questions made in Actavis, whether the skilled reader would have thought that strict compliance with the integers of the patent claim was an essential requirement of the invention, revealed a significant change: the focus was now on the inventive concept. Therefore, the distinction between the invention as a whole and the inventive concept mattered. The invention was that which was claimed, while the inventive concept was the new technical insight conveyed by the invention, the clever bit, as would be perceived by the skilled person, assessed by reference to the specification and the evidence.

Now, as before Actavis, an integer of a claim could not be disregarded without further reasoning. However, the principle was that the scope of a claim was the same as its limits on a single construction. The third Improver question had required the court to consider whether the relevant integer, that corresponding to the alleged equivalent, would have been regarded by the skilled person as an essential part of the inventive concept. Having done so, it was possible for the court to reach a view that, even though the language of the claim did not cover the variant, this did not of itself justify answering yes to the third question.


This decision shows first instance courts continuing to review established principles of construction in the light of Actavis. It is likely that the court's decision on the resulting change to the third Improver question will go to the Court of Appeal and possibly the Supreme Court, to determine whether the presence of a precise numerical limit in a claim should normally be a strong indication that the patentee intended strict compliance with that limit and equivalents have therefore been excluded by the patentee.

Case: Regen Lab SA v Estar Medical Ltd and others [2019] EWHC 63 (Pat).

First published in the March 2019 issue of PLC Magazine and reproduced with the kind permission of the publishers.  Subscription enquiries 020 7202 1200.

About the Author

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Audrey Horton
Professional Support Lawyer
As the knowledge and development lawyer in our Intellectual Property Group based in London, I play a key part keeping the IP team up to date with legal developments and case law, scanning the horizon to ensure we are at the forefront of new trends.

Direct: +44 (0)20 7415 6000

[email protected]

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