Home: Maucher Jenkins

Intellectual Property


Patents | Trade Marks | Designs

News & Commentary

Regeneron v Kymab - Supreme Court reverses Court of Appeal Decision on what constitutes sufficient disclosure

Date: 9 July 2020


The Supreme Court has now issued its decision in the case of Regeneron v Kymab [2020] UKSC 27.


Please click here for the full judgement: Regeneron v Kymab 


Background to the Case


We reported the decision of the Court of Appeal here in May 2018: Welcome guidance from Court of Appeal on sufficient disclosure 


This case relates to the sufficiency of disclosure of Regeneron patents (European Patent (UK) No 1360287 and its divisional European Patent (UK) No 2264163). The invention in these patents relates to a new way of producing a "reverse chimeric locus" to express antibodies containing a murine constant region and human variable region.


Kymab argued at the Court of Appeal that the patents lacked sufficiency of disclosure. This was because the claims covered an embodiment of the invention at the priority date, specifically the embodiment in Example 3 in which a deletion and replacement of a large segment of DNA was described. Kymab therefore argued that the skilled person at the priority date would not have been able to carry out the invention exactly as contemplated in the example.


The Court of Appeal was of the opinion however that the claims of these patents were sufficiently disclosed because "the invention for which protection was claimed amounted to an inventive, indeed ground-breaking, general principle, such that every type of mouse with the specified characteristics would display the particular benefits which the invention was designed to achieve, benefits which would not be displayed by any types of mouse outside the specified range".


The case before the Supreme Court


The question before the Supreme Court when assessing the decision of the Court of Appeal was "whether a product patent, the teaching of which enables the skilled person only to make some, but not all, of the types of product within the scope of the claim, passes the sufficiency test where the invention would contribute to the utility of all the products in the range, if and when they could be made."


In order to assess the principles of sufficiency of disclosure, the Supreme Court set out the following example:


"Suppose that five types of product (types A to E) were all claimed to be more efficient or useful than their predecessors by the application to their manufacture of the same new invention. The patentee made separate claims in relation to each type, all supported by the same disclosure. Each claim would be subjected to the sufficiency test: could a product of that type be made by use of the teaching in the patent, coupled with the existing common general knowledge? Suppose that types A and B could but C, D and E could not. Then claims A and B would be valid, and the remainder invalid. But now suppose that all five types were covered by the more compendious wording of a single claim. Would this enable the patentee also to obtain a monopoly for the making of types C, D and E? Surely not."


The Supreme Court did not doubt that the Court of Appeal accepted this analysis as a general rule, but that the Court of Appeal had concluded that the reward given to the patentee should be commensurate with the contribution which the invention makes to the art. In light of this the Court of Appeal were minded to believe that the scope of protection for an invention which consists of a new generally applicable principle therefore may encompass not only in products which can currently be made, but equally in products which will only be capable of being made in the future, after further inventive research and development.


In order to assess this, many of the key decisions from the UK courts and the EPO Board of Appeal regarding sufficiency of disclosure were considered in the context of this case. The decision outlines two different line of case law:


1) Exxon/Fuel Oils (T 409/91) in which the Board of Appeal stated "in order to fulfil the requirement of article 83 EPC, the application as filed must contain sufficient information to allow a person skilled in the art, using his common general knowledge, to carry out the invention within the whole area that is claimed". They also used Unilever/Detergents (T 435/91) in which the Board of Appeal stated "the requirement of sufficient disclosure can only mean that the whole subject matter that is defined in the claims, and not only a part of it, must be capable of being carried out by the skilled person without the burden of an undue amount of experimentation or the application of inventive ingenuity;



2) Genentech I/Polypeptide expression (T 292/85) in which the Board of Appeal held that "unless variants of components are also embraced in the claims, which are, now or later on, equally suitable to achieve the same effect in a manner which could not have been envisaged without the invention, the protection provided by the patent would be ineffectual."


The Supreme Court however did not see a divergence between these two lines of case law because:


"the Polypeptide line of cases did disclose a sufficient general principle which, without any further inventive step, would enable the skilled person to work the relevant invention by using, as input elements, examples of those components described generally in the claims, which were unavailable as at the priority date, in order to make products across the scope of the claim. The fact that the claim permitted alternative examples of input elements, as yet unavailable at the priority date, is the exception to the requirement for enablement across the whole scope of the claim".


This was not the case with the Detergents/Exxon line of case law and it is into this line of case law that the Supreme Court believed that the claims of the patents in question belonged because "the inventive shortfall at the priority date lay not in the range of possible inputs to which the invention could be applied, but in the inability to create a Reverse Chimeric Locus involving the whole (or anything more than a very small part of) the human variable region." To put it another way, an inventive step was required in order to be able to make the large deletion and replacement set out in example 3 and put the invention into practice across its entire scope of protection.


The Supreme Court set out a set of principles based on the European and UK authorities summarised as follows:


i) The requirement of sufficiency exists to ensure that the extent of the monopoly conferred by the patent corresponds with the extent of the contribution which it makes to the art.


ii) In the case of a product claim, the contribution to the art is the ability of the skilled person to make the product itself, rather than (if different) the invention.


iii) Patentees are free to choose how widely to frame the range of products for which they claim protection. But they need to ensure that they make no broader claim than is enabled by their disclosure.


iv) The disclosure required of the patentee is such as will, coupled with the common general knowledge existing as at the priority date, be sufficient to enable the skilled person to make substantially all the types or embodiments of products within the scope of the claim.


v) A claim which seeks to protect products which cannot be made by the skilled person using the disclosure in the patent will be bound to exceed the contribution to the art made by the patent.


vi) This does not mean that the patentee has to demonstrate in the disclosure that every embodiment within the scope of the claim has been tried, tested and proved to have been enabled to be made. Patentees may rely upon a principle of general application if it would appear reasonably likely to enable the whole range of products within the scope of the claim to be made. This may however pose a risk if challenged at trial.


vii) Nor will a claim which in substance passes the sufficiency test be defeated by dividing the product claim into a range denominated by some wholly irrelevant factor. The requirement to show enablement across the whole scope of the claim applies only across a relevant range.


viii) Enablement across the scope of a product claim is not established merely by showing that all products within the relevant range will, if and when they can be made, deliver the same general benefit intended to be generated by the invention, regardless how valuable and ground-breaking that invention may prove to be.


The Decision


In light of the above assessment the Supreme Court determined that the claims of the Regeneron patents did not meet the requirements for sufficiency because they could not be enabled at the priority date without the application of inventive reasoning. The Supreme Court rejected the approach of the Court of Appeal because it has misapplied the law and its approach could not be regarded as a legitimate development of the law. In the opinion of the Supreme Court the approach taken by the Court of Appeal would be "to water down that requirement" and "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 concluded:


"What matters is that it is settled law, in relation to a product claim, that sufficiency requires substantially the whole of the range of products within the scope of the claim to be enabled to be made by means of the disclosure in the patent, and this both reflects and applies the principle that the contribution to the art is to be measured by the products which can thereby be made as at the priority date, not by the contribution which the invention may make to the value and utility of products, the ability to make which, if at all, lies in the future."


It is perhaps interesting to note that this was a majority decision with Lady Black writing a dissenting opinion in favour of the approach of the Court of Appeal.


Practical consideration


This will be a disappointing outcome for many patent proprietors in this and many other fields of technology and it appears to introduce a very high bar regarding sufficiency of disclosure.


While the Supreme Court did state that an applicant for a patent application is not required to demonstrate that each variant of a product was made and described in the disclosure of a patent application in order to be sufficiently disclosed, this is certainly the impression that many will take from this judgement. This was not lost on the Supreme Court, but they were also not inclined to provide much comfort to patent applicants and acknowledged that "the consequence of confining the patentee with a ground-breaking invention to protection only over a range of products which the invention currently enables to be made at the priority date will give the patentee scant and short-lived reward for their efforts and ingenuity, viewed in particular with the benefit of hindsight."


It does however provide a clear warning to applicants regarding the importance of providing evidence that a product or process has a technical effect in the ranges set out in a patent application and that this is supported by experimental evidence. While a broad claim to the general principle will always be more desirable than being confined to a specific range, dependent claims that define a scope of protection for which sufficiency of disclosure can be is readily demonstrated may prove invaluable to maintaining validity of a patent during post grant proceedings.


For further information on our team and services in this area, please follow the links below:


Life Sciences & Chemistry




Click here for Deutsch