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Regeneron v Kymab – Principles capable of general application

13th Jul 2020

In his recent article, Robin Ellis summarised the key take-home messages from the UK Supreme Court judgement in Regeneron v Kymab.

In this article Andrew Carridge takes a more in-depth look into the concept of a ‘principle capable of general application’, exploring when broad claims may be justified and when claims may legitimately cover as yet undiscovered embodiments.

In exploring this concept, the Supreme Court made a distinction between two lines of case law which they termed: the ‘Detergents/Exxon’ line and the ‘Polypeptide’ line.


Brief recap

Regeneron developed a hybrid chimeric antibody gene structure which included human parts (V(D)J segments, forming the variable regions of antibodies) and mouse parts (forming the constant regions of antibodies), known as a “reverse chimeric locus”. This overcame issues associated with human rejection of mouse antibodies and “immunological sickness” in mice.

Claim 1 of the patent was as follows:

A transgenic mouse that produces hybrid antibodies containing human variable regions and mouse constant regions, wherein said mouse comprises an in situ replacement of mouse VDJ regions with human VDJ regions at a murine chromosomal immunoglobulin heavy chain locus and an in situ replacement of mouse VJ regions with human VJ regions at a murine chromosomal immunoglobulin light chain locus.

At first instance, in the High Court, the patent was held invalid for lack of sufficiency. In the Judge’s view the invention did not work across the scope of the claim, because the claims covered the deletion of a large stretch of mouse sequences in the mouse genome as well as the insertion of large human sequences. A person of skill in the art would not have been able to produce a hybrid gene structure in which the whole of the human variable region was combined with the mouse constant region. Expert evidence showed that swapping sequences that are of a large size were far beyond the capabilities of the skilled person at the priority date.

The Court of Appeal found that the person of skill in the art could work the invention but only for a reverse chimeric locus which included very small amounts of human parts. Nevertheless, the Court of Appeal considered that the invention should be regarded as sufficiently enabled across the scope of the claims if it can be seen that it will in due course benefit all products in the range, provided that, as at the priority date, the teaching in the patent enables at least one type to be made immediately. Since the reverse chimeric locus would be likely to deal with murine immunological sickness in mice whose genomes were fitted with “all or any” amount of the human variable segments, up to and including the whole of the human variable region, its invention was one of those principles of general application which should be regarded as enabled across the whole range contemplated by Claim 1. A monopoly over the making and exploitation of the whole range would correspond with the contribution made by the reverse chimeric locus to the art. The focus by the Court of Appeal was on the effect of the reverse chimeric locus across the scope of the claims rather than the ability to make the reverse chimeric locus across the scope of the claim.

The Supreme Court, as we now know, overturned the Court of Appeal ruling stressing, inter alia, the following concepts.

  • 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. That is what, in the context of a product claim, enablement means.
  • A claim which seeks to protect products which cannot be made by the skilled person using the disclosure in the patent will, subject to de minimis or wholly irrelevant exceptions, be bound to exceed the contribution to the art made by the patent, measured as it must be at the priority date.
  • 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.

In reaching their decision, the Supreme Court  made numerous references to EPO (European Patent Office) Board of Appeal case law. This is not surprising given the Supreme Court was keen to stress that “[T]he interpretative objective is to strive for consistency between European and UK patent law”


Detergents/Exxon line

T 409/92 was one of the key EPO decisions relied on by the Supreme Court. In T 409/92,  it was discussed how at certain temperatures, wax crystals suspended in diesel fuel tend to clog fuel filters in diesel engines. Exxon claimed a monopoly over fuel oils which, within specified temperatures, had wax crystals having an average particle size of less than 4,000 nm. This was challenged on the basis that the claimed range was from 1 nm to 3,999 nm, but the teaching in the patent did not enable fuel oil to be produced (by the insertion of additives) with a wax crystal size below 1,000 nm. This was a relevant range because the smaller the crystal the more easily it would pass through a filter. Exxon sought to defend the claim by asserting that the invention embodied a general principle, applicable across the whole claimed range, that small crystals do not clog filters. However, in T 409/92, the following was held:

“In other words, in the present case there is absolutely no doubt that all these claims must be so construed as to relate to fuel oils containing wax crystals smaller than 1,000 nanometres. The appellant has admitted that no way of obtaining such fuel oils was disclosed or could be found in the body of relevant common general knowledge. However, in the Board’s judgment, 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.”

Even if there was a principle capable of general application, the Board held that this was irrelevant:

“regardless of whether or not the alleged ‘principle’ to avoid the so-called ‘cold filter plugging’ (or clogging) by reducing the size of the wax crystals would be novel and inventive.”

The Supreme Court relied on T 435/91 for the requirement that enablement across the scope of the claim is generally applicable to all inventions.

“In the Board’s judgment the criteria for determining the sufficiency of the disclosure are the same for all inventions, irrespective of the way in which they are defined, be it by way of structural terms of their technical features or by their function. In both cases 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.”


Polypeptide line

  • T 292/85 (Genentech I/Polypeptide expression)

This case concerned a patent claiming processes and resulting products which produced a uniform stream of specified polypeptides. The claims referred to “bacterium”, “regulon”, or “plasmid” – terms wide enough to embrace types which had yet to be made available under the then state of the art. The Examining Division had refused the application on the grounds that it lacked sufficiency because all embodiments within the claims must have been capable of being carried out by the skilled person at the priority date and in a repeatable manner without practicing inventive skill. In the Examining Division’s view, no claims should rely on constituents which represent further inventions. In addition to the impossibility of providing such embodiments at the present, the later patentability of such constituent variants might be adversely affected. The Examining Division was of the view that claims should, in effect, at least be limited to what is available at the priority date, i.e. known bacteria, plasmids and DNA relating to known polypeptides.

The Board of Appeal disagreed with the Examining Division.

“3.1.2 There is, however, in the opinion of the Board, no such requirement in the European Patent Convention, nor is such principle established in normal patent practice within the Contracting States. The suggested features in the claims are essentially functional terms in this particular context, in spite of structural connotations, and may cover an unlimited number of possibilities. It follows that the features may generically embrace the use of unknown or not yet envisaged possibilities, including specific variants which might be provided or invented in the future.

3.1.3 What is also important in the present case is the irrelevancy of the particular choice of a variant within the functional terms ‘bacteria’, ‘regulon’ or ‘plasmid’. It is not just that some result within the range of polypeptides is obtained in each case but it is the same polypeptide which is expressed, independent of the choice of these means …

3.1.5 … 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. Thus it is the view of the Board that an invention is sufficiently disclosed if at least one way is clearly indicated enabling the skilled person to carry out the invention.”

A claim to protect a means of preparing fructose was challenged for sufficiency on the ground that a certain type of input element (a certain strain of fungi) falling within the claim only became available to persons skilled in the art after the priority date. The challenge was rejected in part because the description contained sufficient teaching to enable the invention to be used with that new input element, once available.

So what are the main concepts that distinguish these two lines of case law?


Detergents/Exxon line vs. Polypeptide line

In the Polypeptide line, even if the claim encompasses embodiments unavailable at the priority date, a sufficient general principle is established which, without any further inventive step, would enable the skilled person to work the invention across the scope of the claims and apply the general principle to such embodiments when they are discovered.

By contrast, in the Detergent/Exxon line there is no general technical principle by which the skilled person could achieve the desired result across the whole range of the claimed embodiments. So, although the claims encompass embodiments that have not yet been developed, there is not enough teaching to indicate how, without using inventive skill, such embodiments could conceivably be made at the priority date.

In the Regeneron v Kymab judgement, the Supreme Court considered how these two concepts could be applied to the case at hand.

“It is convenient at this point to explain why the present case falls on the Detergents/Exxon side of this line. The reason why Claim 1 fails to enable the skilled person to make mice with Reverse Chimeric Loci across the whole range of the human variable regions of the hybrid antibody gene structure is not because any of the V, D and J segments had yet to be discovered or “mapped” by the priority date, or even because any of them could not be inserted into mice. The whole of the human variable region gene locus had already been mapped. It could be (and had been) inserted into mice, but only when attached to the human constant region genes, thereby causing murine immunological sickness. The problem facing those skilled in the art at the priority date was that there was no known way, even using the teaching in the patents, to combine more than a very small part of the human variable region gene locus with the endogenous murine constant region gene locus, in the same hybrid gene structure. It took several years, and significant further inventive steps, before methods were developed sophisticated enough to accommodate the whole of the human variable and murine constant region genes in a single hybrid gene structure. Thus 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.”

Based on this, one may consider a hypothetical situation in which the patent had taught how to make a reverse chimeric locus containing large portions of the human variable region and the mouse constant region, but that not all of the human V, D and J segments had been discovered, or had been mapped. Given these hypothetical facts, and based on the Supreme Court’s comments, it would seem that the patent’s broad claim, which would cover the yet undiscovered human V, D and J segments, would fall with the Polypeptide line of cases and would have been sufficient. Once the V, D and J gene segments had been discovered, it would seem to take no inventive skill to incorporate them into the reverse chimeric locus.

In Robin’s article he applied the analogy of teleportation to Regeneron v Kymab. In his analogy scientists had found a way to teleport an iron nail over a distance of 5 micrometres.  The scientists filed a patent, explaining exactly how they teleported the iron nail and claiming “a method for teleporting an object from a first location (A) to a second location (B)”. Based on Regeneron v Kymab, the patent would not be sufficient because it only enables the teleportation of a non-complex, inanimate object, over a very short distance yet it claims a monopoly which includes teleportation of any object including, for example, complex organic matter, over thousands of miles. Because teleporting complex organic matter over thousands of miles is likely to require further development and multiple “inventive steps” before it works, the patent is insufficient with respect to the broad inventive principle it is trying to protect. This example would appear to fall squarely on the Detergent/Exxon line of cases.

Assume, however, that the scientists had been able to demonstrate teleportation of a wide range of objects over a wide range of distances, including, for example, how to teleport a dog a distance of 10 kilometres. Based on this, it seems as though the scientists may have found a general concept that could feasibly be used to teleport anything over any distance. However, if they filed a patent that claimed “a method for teleporting an object from a first location (A) to a second location (B)”, the patent claim is broad enough to cover as yet untested objects or undiscovered objects. However, given the apparent general applicability of the concept, it would appear to require no inventive skill to apply the same concept to teleport an object that is yet to be discovered or an object that has not (yet) been tested (such as a human). Such an example would appear to fall on the Polypeptide line.


This article is for general information only. Its content is not a statement of the law on any subject and does not constitute advice. Please contact Reddie & Grose LLP for advice before taking any action in reliance on it.



Andrew Carridge
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