BREAKING: Kymab caught the mouse as sufficiency strengthened by UK Supreme Court in Regeneron battle ([2020] UKSC 27)

The UK Supreme Court today found Regeneron's valuable antibody platform technology patents invalid for insufficiency. In doing so, the UK Supreme Court overturned the Court of Appeal decision and confirms the strong sufficiency requirement in the UK. The Supreme Court decision places emphasis on the principle of sufficiency that a patent claim should be enabled across its whole scope. As summarised by the UK Supreme Court itself, the Court of Appeal reasoning was seen as increasing the rewards obtainable by inventors in a complex, rapidly developing field like genetic engineering. The Supreme Court found in a majority ruling that the Court of Appeal swayed the balance too much in favour of patentees in a way that was not warranted by UK or EPO law. The full UK Supreme Court judgment can be read here.

Case Background

The Regeneron patents in question (EP2264163 and EP1360287) related to mice genetically modified to possess human antibody genes. Historically, the development of therapeutic antibodies relied on the cloning of specific human antibody genes into a mouse. The Regeneron mice (VelocImmune) produce human antibodies that respond naturally to antigenic challenge and thus mirror the normal immune reaction. This allows production of a diverse spectrum of antibodies against the same target within a single mouse.

Regeneron brought proceedings against the Cambridge-based biotech company Kymab for infringement of the VelocImmune patents. Kymab counterclaimed that the patents were invalid for insufficiency. In the High Court, the late Mr Justice Heney Carr agreed with Kymab that the claims were insufficient. The High Court decision was based on evidence that the one example in the patent of how to make the claimed mouse would not have worked. Particularly, the method required the insertion and deletion of large sections of DNA. Such a method was not possible at the priority date. The High Court thus concluded that the patent did not enable mice falling under the claims to be made.

Kymab appealed to the Court of Appeal. The Court of Appeal disagreed with the High Court, and found the patents sufficiently disclosed. Lord Justice Kitchin (as then was) agreed with the High Court that the example provided in the patent would not have worked.  However, Lord Justice Kitchin (as then was) found that a skilled person was not bound to follow the examples provided in the patent. Instead, the skilled person could use common general knowledge to make obvious changes to the method. This would allow a skilled person to make a mouse falling under the scope of the claims. A skilled person would not be able to make all types of mice falling under the scope of the claims. However, the ability of the skilled person to make at least one type of mouse according to the invention amounted to sufficiency of disclosure, given that the invention related to a broad general principle.

The Court of Appeal reasoned that if the patented invention related to a general principle of usefulness across a range of potential product types, it is not necessary for the patent to enable production of all of these product types. If the patentee was limited to a monopoly over only the products that could be immediately made, this would deprive the patentee of any reward for the broader applicability of their invention. Importantly, the types of mice that now represent the most valuable commercial embodiment of the invention could not have been made at the priority date, and required further inventions to be realised. However, for Lord Justice Kitchin, the broad general contribution represented by the patent should none-the-less be rewarded.

UK Supreme Court Decision

In a majority judgment, the UK Supreme Court found the Court of Appeal's reasoning logically sound, but ultimately considered it to be inconsistent with the UK and EPO law on insufficiency.  In particular, the UK Supreme Court understood the principle that a patent should enable substantially all products within the scope of a claim at the priority date to be part of the bedrock of both UK and EPO law. In the words of Lord Briggs, who led the majority judgment, "[t]o water down that requirement would tilt the careful balance thereby established in favour of patentees and against the public in a way which is not warranted by the EPC, and which would exceed by a wide margin the scope for the development of the law by judicial decision-making in a particular Convention state".

The Supreme Court thus did not think the patent bargain was satisfied if the benefits of an invention could only be realised after the priority date, if and when all embodiments within the range could be made. Kymab's appeal was therefore upheld, and the Regeneron patents found invalid for insufficiency.

In a dissenting view, Lady Black first noted agreement between the Court of Appeal and Supreme Court on the legal principles. For Lady Black, the two courts disagreed in the application of these principles to the case in question. Contrary to the Supreme Court majority, Lady Black agreed with the Court of Appeal that the invention related to a broad general principle, that this principle was employed in all mice across the range of the claim, and that the patent should be rewarded by a commensurate broad scope of protection.

So are the UK and EPO Boards of Appeal currently aligned on sufficiency? The answer to this question is not straightforward, and the IPKat will provide some further thoughts in coming days.
BREAKING: Kymab caught the mouse as sufficiency strengthened by UK Supreme Court in Regeneron battle ([2020] UKSC 27) BREAKING: Kymab caught the mouse as sufficiency strengthened by UK Supreme Court in Regeneron battle ([2020] UKSC 27) Reviewed by Rose Hughes on Wednesday, June 24, 2020 Rating: 5


  1. Making a fundamental invention and then loosing the patent for insufficiency of the claimed invention smells like a fundamental error in the process. Maybe product claims were the wrong category for the contribution of the invention. A process claim with the benefits of Article 64(2) EPC may have done the trick. In any case, an instructive ruling.

  2. That's a good comment from NFH. Was the patent owner unwilling to come down to a narrower claim for fear of letting the infringer escape?

    In the meantime though, the pemetrexid (di-sodium) case might point the way forward: claim relatively focussed, and let the DoE do the rest.

  3. To NFH: Kymab were using a different process. So a method claim or a product claim directed to Regeneron's actual mouse would not have helped.

    Whatever the specifics of the case, the argument "your patent wouldn't enable the production of my product due to this new and improved feature, therefore your patent is insufficient" will presumably become more common.

  4. Justice was done. The patentee should not have sued a party whose product clearly indicated lack of enablement of the patent. The Supreme Court I am sure was shocked by the fact that the patentee was suing based on a claim that had an enablement hole exactly where the infringement was. That was asking for trouble, and it paid the price

  5. As far as the two patents are concerned, the following can be said:
    EP1360287 has been maintained in amended form after the remaining opponent has failed to file grounds of appeal following the maintenance in amended form after a first appeal. In a first decision the OD had revoked the patent.
    EP2264163 is based on a divisional of EP1360287. The opposition has been rejected and appeal proceedings are pending. Since February 2019 nothing has happened in appeal….. It is to be hoped that the board will now look into the matter as at least a decision on sufficiency has been given by the UK Supreme Court.

    Sufficiency and infringement by equivalents are two different topics which should not be mixed.

    In the Kymab case, it was clear that the only one example given in the patent was not working. In this respect the present case cannot be compared with the pemetrexed disodium case, as in the latter there was one working example disclosed.

    A broad general contribution does not have to be rewarded if there is not at least one way disclosed how to implement that general contribution. Allowing this kind of patent would actually stifle research. It appears more to be then a scientific theory which is as such not patentable. Patents cannot be granted on more theoretical considerations.

    The UK Supreme Court was right in stating that the patent bargain was not satisfied if the benefits of an invention could only be realised after the priority date, if and when all embodiments within the range could be made.

    In T 875/11 it was held that an example was not necessary in order to enable an invention, but here it was about a device and the strength of a hoisting cable had to be exceeding 2000N/mm2. The open range was not a bar to sufficiency. In T 2146/09, one example was given, but the OD was held to be too restrictive in its interpretation of Art 83 in the case of a CII.

    Those cases are quite different from the present one which is in a totally different field in which sufficiency plays a much bigger role.

    I would therefore not say that the UK and the EPO Boards of Appeal are not aligned on sufficiency.

    As said, pemetrexed disodium is not a case which can point the way forward in matters of sufficiency. Sufficiency was never at stake in this case. There was one clear way, but only one, to carry out the invention, that is pemetrexed disodium.

    That decision of the UK court is actually a premium for slap dash and quick drafting. The examiner in charge was right to request the limitation to pemetrexed disodium as it was the only example given in the whole application. He should however have insisted to bring the description in accordance with what was actually claimed. By leaving in the description a lot of gobbledygook it allowed the applicant/proprietor to later claim much more than it had actually contributed to the art.

    After pemetrexed disodium how will it possible to draft a reliable FTO study? It is nice to refer to the DoE, the problem is that nowhere, not even in the protocol on interpretation of Art 69, a definition of what an equivalent should be can be found. If it was an attempt to overcome the disastrous “Improve” decision, a better case than pemetrexed disodium should have been chosen by the UK Supreme Court.

  6. How was it, that for four of the Supreme Court Five, the argument "protection commensurate with the contribution" failed?

    The answer is at para. 54, where Exxon and Biogen are accorded the status of holy writ. For Lord Briggs, in patent law, an inventive concept is either i) a product or ii) a process. Nothing else is conceivable. So, given the thoroughly established, indeed unassailable, law of sufficiency of a "product claim", it was "end of story" as soon as the claim in front of his nose is agreed to be (as in Biogen) a "product claim".

    When a Supreme Court is obliged to choose between a desirable objective "commensurate with the contribution" and a public policy imperative "enabled over the full scope" it has, in reality, no choice but to uphold the imperative. Otherwise, the results will be unhelpful and immediately problematic.

    I'm left a bit disappointed at the paucity of enquiry and analysis of the situation when an "inventive and ground-breaking general principle" is claimed as a "product". Given that the inventor of every little improvement to any old household article of commerce gets a full 20 years, it seems a bit poor to deprive those who disclose a game-changing ground-breaking general principle of any protection just because they chose to express their inventive concept in the form of a "product claim".

    But I don't practise in this field. Perhaps those that do can reassure me that they still can secure a scope of protection commensurate with their contribution to the art.

  7. The question raised by Max Drei is whether the applicant was correctly advised in his patenting effort. In view of the result doubts can be expressed.

    Bringing in an application about an apparently ground-braking technique an example which does not work does not appear very responsible.

    Another question to be asked is whether the invention was ripe enough to be subject-matter of a patent application with all the requirements which go on a par. It seems that the rush to apply for a patent was detrimental to a valuable application.

    When looking at case law in the biotech area, lack of sufficiency is one of the major reason for refusal or revocation. It should thus not come as a surprise when such a patent is revoked for this ground.

  8. In my haste to stimulate an enjoyable thread I missed the point that there was only one Example in the patent, and it did not work. (Thanks Attentive). No wonder then, that the judge at first instance baulked at upholding the patent.

    Nevertheless, I'm still intrigued by the challenge of how to deliver commensurate scope of protection when the claimed subject matter really does correspond to a "ground-breaking" principle. Only after the virgin ground has been "broken" does it emerge how to cultivate that fresh ground. It seems to be (still) a bit harsh to stipulate that the inventor who, shall we say, discovers a hitherto unrecognised scientific principle can obtain protection commensurate with the contribution that makes to technical progress only by teaching in the patent application how to "work" the principle all over its potential scope.

    But perhaps I'm worrying unnecessarily. After all, like the pemetrexed case, this case was also one in which unfortunate drafting made it very special. Will such Supreme Court cases remind those who set budgets for patent departments a bit more aware that the drafting stage is the first step in any patent litigation, and therefore should be adequately funded? I do hope so.

  9. Dear Max Drei,

    Thanks for your further comment. From all my contacts with the profession I can draw a strong conclusion: saving at the drafting stage backfires, sometimes very badly.

    What you missed originally cannot be saved later, as especially the problem of added is always in the background.

    A good way to discriminate between Art 83 and Art 84, is that when there is a true problem of sufficiency, it can in general only be overcome with adding matter. So you are left to choose between two evils, both lethal for your application/patent.

    When it is a problem of support under Art 84, it can be overcome if the claims is limited to what has actually been disclosed. The broader the claim, the better it is to give some examples in the original disclosure and not just at the beginning of a claimed range. The better it will also be possible to justify inventive step. Further data is only allowable when it is at least plausible that what is claimed works as it is claimed.

    It is also a problem of timing. Filing an application with only sketchy or unreliable data is also not advisable. But the competition is never sleeping. And we do not have what is called a continuation or a continuation in part on this side of the Atlantic.

    The job of patent representative can give a lot of satisfaction and rewards, but he will always be dependent on the information he gets from his client. This should also not be forgotten.

  10. Attentive Observer, having been faced with the decision on countless occasions, I would say it is often impossible to say exactly when a complex biotech case should be filed, i.e. how much data is needed? Inventive step problems due to the prior art continues to be the major issue on biotech cases, and so the best rule seems to be to file as soon as possible, and take risks on sufficiency. Probably here also the decision on when to file was correct because they are deemed inventive.


All comments must be moderated by a member of the IPKat team before they appear on the blog. Comments will not be allowed if the contravene the IPKat policy that readers' comments should not be obscene or defamatory; they should not consist of ad hominem attacks on members of the blog team or other comment-posters and they should make a constructive contribution to the discussion of the post on which they purport to comment.

It is also the IPKat policy that comments should not be made completely anonymously, and users should use a consistent name or pseudonym (which should not itself be defamatory or obscene, or that of another real person), either in the "identity" field, or at the beginning of the comment. Current practice is to, however, allow a limited number of comments that contravene this policy, provided that the comment has a high degree of relevance and the comment chain does not become too difficult to follow.

Learn more here:

Powered by Blogger.