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Following the highly anticipated decisions in Warner-Lambert v Generics Ltd with regards to plausibility and Actavis v Lilly in relation to infringement, the UK High Court has now considered both tests in present case.


Genentech is the proprietor of European patent (UK) No. 1 641 822 entitled “Il-17A/F heterologous peptides and therapeutic uses thereof”. Genentech does not at present have a product covered by the patent but Lilly market an antibody under the trade mark “Taltz” as a treatment for moderate to severe plaque psoriasis and psoriatic arthritis in adults. Taltz is an antibody to IL-17A which also binds to IL-17A/F.

Lilly filed a revocation action with respect to Genentech’s European patent, alleging that all of the claims are invalid on grounds of lack of novelty, obviousness and insufficiency. They also sought a declaration that dealings in Taltz do not infringe Genentech’s European patent. Genentech counterclaimed for infringement.

Although Genentech’s European patent as granted contained claims directed to treatment of any immune-related disorder, Genentech applied to amend the patent such that only claims directed to rheumatoid arthritis and psoriasis were maintained. Thus, the amended claim set included product claims to anti-IL-17A/F antibodies per se, first medical use claims and second medical use claims to use of the anti-IL-17A/F antibody in the treatment of rheumatoid arthritis or psoriasis.

Novelty and Obviousness

The judgement is extremely lengthy in this regard, but the conclusion reached was that the product claims and first medical use claims were obvious. Arnold J also held the second medical use claims obvious in so far as they related to rheumatoid arthritis.

The novelty argument was dismissed, with Arnold J holding that working the prior art would not inevitably produce the claimed antibodies.


With regards to the second medical use claims in so far as they related to psoriasis, Arnold J decided to analyse sufficiency first, likely because he knew the claims would fail the plausibility benchmark as confirmed in Warner-Lambert.

Arnold J started his analysis of sufficiency by reiterating the law on plausibility as confirmed by Lord Sumption in Warner-Lambert, with particular emphasis on the seven propositions made by Lord Sumption in relation to the plausibility test:

  1. The proposition that a product is efficacious for the treatment of a given condition must be plausible.
  2. It is not made plausible by a bare assertion to that effect, and the disclosure of a mere possibility that it will work is no better than a bare assertion.
  3. The claimed therapeutic effect may well be rendered plausible by a specification showing that something was worth trying for a reason, i.e. not just because there was an abstract possibility that it would work but because reasonable scientific grounds were disclosed for expecting that it might well work. The disclosure of those grounds marks the difference between a speculation and a contribution to the art.
  4. Although the disclosure need not definitively prove the assertion that the product works for the designated purpose, there must be something that would cause the skilled person to think that there was a reasonable prospect that the assertion would prove to be true.
  5. That reasonable prospect must be based on a direct effect on a metabolic mechanism specifically involved in the disease, this mechanism being either known from the prior art or demonstrated in the patent per se.
  6. The effect on the disease process need not necessarily be demonstrated by experimental data. It can be demonstrated by a priori reasoning. For example, and it is no more than an example, the specification may point to some property of the product which would lead the skilled person to expect that it might well produce the claimed therapeutic effect; or to some unifying principle that relates the product or the proposed use to something else which would suggest as much to the skilled person.
  7. Sufficiency is a characteristic of the disclosure, and these matters must appear from the patent. The disclosure may be supplemented or explained by the common general knowledge of the skilled person. But it is not enough that the patentee can prove that the product can reasonably be expected to work in the designated use, if the skilled person would not derive this from the teaching of the patent.

After consideration of the evidence before him, and with a strong focus on mind of the person skilled in the art at the filing date of Genentech’s patent, Arnold J came to the conclusion that the skilled person would not have regarded it plausible that an anti-IL-17A/F antibody would have a discernible therapeutic effect on psoriasis. Arnold then gave five reasons for his decision:

  1. The absence from the Patent of any experimental data concerning the role or effect of IL-17A/F, let alone an anti-IL-17A/F antibody, in psoriasis.
  2. The absence of any discussion of the role or effect of IL-17A/F in psoriasis.
  3. The limited support for IL-17A/A (let alone IL-17A/F) having a pathogenic role in psoriasis provided by the papers cited in the Patent, particularly given the common general knowledge as to all the other cytokines which were implicated in psoriasis.
  4. The fact that the Patent shows that IL-17A/F is an order of magnitude less potent than IL-17A/A.
  5. The fact that the specification claims efficacy against a broad list of conditions which it is wholly implausible that an anti-IL-17A/F antibody (or any form of IL-17A/F therapy) would be effective against.


Having concluded that all claims of the patent were invalid, Arnold J moved on to the consideration of infringement.

After concluding that the phrase “which specifically binds to” is not limiting, Arnold J found in Genentech’s favour, namely that on a normal interpretation of the claims, dealings in Taltz would amount to infringement.

Although the issue of equivalence was not directly relevant because of Arnold’s conclusion with respect to the normal interpretation of the claims, it was nevertheless considered.

Answering the three questions set out by Lord Neuberger in Actavis v Lilly Yes, Yes, No, Arnold J found the claims to also be infringed under the doctrine of equivalents.

Thus, in conclusion the patent was found invalid but infringed.

On the same day that the present decision was issued, Arnold J also handed down a second judgement in relation to Genentech’s Supplementary Protection Certificate (SPC) application for anti-17A/F antibodies which relied on Genentech’s European patent (UK) No. 1 641 822 but Lilly’s Marketing Authorisation for Taltz – read article here.

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 Our news articles are for general information only. They should not be considered specific legal advice, which is available on request.


Our articles are for general information only. They should not be considered specific legal advice, which is available upon request. All information in our articles is considered to be accurate at the date of publishing.


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