In July this year, the UK’s Supreme Court introduced a doctrine of equivalents into the patent infringement test (Actavis v Eli Lilly as reported here). The ruling raised many questions, particularly as to whether the doctrine of equivalents has a role in the assessment of novelty. The first decision applying the Supreme Court’s decision has recently issued from the UK’s High Court (Generics (U.K.) Limited and others v Yeda Research and Development Company Limited and others [2017] EWHC 2629 (Pat)), suggesting that the doctrine of equivalents does not apply to novelty. This judgement signals a radical departure from the previous position in the UK that a claim should be interpreted in the same manner, and has the same scope, for the purposes of considering both novelty and infringement

As explained in our previous post, the Supreme Court ruled that a proper construction of a claim for the purpose of assessing infringement must take account of equivalents. However, the Supreme Court judgement is silent on whether the doctrine of equivalents has any impact on the assessment of novelty. This issue has now been tackled by Mr Justice Arnold in the above-mentioned High Court ruling, albeit only briefly.

The High Court heard arguments on the impact of the Supreme Court’s decision on claim interpretation with regard to novelty.  The Claimant’s position was that it remained the law that a claim lacked novelty if a prior publication disclosed subject-matter which, if performed, would necessarily infringe the claim. Moreover, even if the prior art subject-matter would not fall within the claim on its proper interpretation, it was sufficient that the subject-matter would infringe the claim under the doctrine of equivalents. Otherwise, a claim could be infringed by a person who did exactly what the prior publication taught, yet the claim would be novel over that prior publication.

However, Arnold J did not find this argument to be persuasive. Instead, he agreed with the Defendant, who submitted that a claim would only lack novelty if the prior publication disclosed subject-matter which fell within the claim on its proper interpretation. Thus, when assessing novelty it is not sufficient that the subject-matter would infringe the claim applying the doctrine of equivalents.

Arnold J concluded that the doctrine of equivalents has no application in the law of novelty. He declined to consider this issue in great detail, because he found the patent to be invalid for lack of an inventive step. However, his judgement highlights the importance of this issue, because he explained that if the doctrine of equivalents were applied to the assessment of novelty, the patent claims would have been anticipated. He also acknowledged that ultimately, guidance from the Supreme Court on this issue will be needed.

For now, it seems that the UK is left with the somewhat paradoxical situation where the scope of protection for infringement goes beyond the meaning of the claim, but the test for novelty uses only the meaning of the claim without the extra scope provided for infringement. Therefore, a granted patent may cover more than what it had to overcome in order to be granted.  This is commonly referred to as the “angora cat paradox”, which potentially allows a patentee to argue for a broad claim scope for the purpose of infringement (a fluffy dry cat), but to argue for a narrower claim interpretation for the purpose of assessing novelty (a wet cat).

Whilst this situation may seem to favour patentees, it also poses interesting challenges for patent applicants wishing to distinguish their claims from prior art, particularly prior art under Article 54(3) of the European Patent Convention (an earlier-filed, but later-published patent application) which is citable for the purpose of assessing novelty, but not inventive step.

It remains to be seen to what extent alleged infringers may be able to rely on the so-called “Gilette” defence under which anything that was known from the prior art either anticipates (and therefore invalidates) a claim, or does not infringe it. A variant of this defence, the so-called “Formstein defence”, is established practice in Germany.  Under the Formstein defence, claims are precluded from extending under the doctrine of equivalents to embodiments which are invalid for lack of novelty or inventiveness.  Perhaps UK practice will develop to align the Gillette defence more closely with the Formstein defence.


“Another question which arises in the light of the Supreme Court’s decision is what effect, if any, this has on the law of novelty. This issue is not addressed in the judgment of Lord Neuberger, and he makes no reference to Synthon v SKB. It will require another decision of the Supreme Court to supply a definitive answer to the question.”