The UKSC has introduced a new test for breadth of claim sufficiency for product claims
 
The full judgment can be accessed here and the UKSC’s press summary here.
 
Summary
 
The UKSC has confirmed that claims to classes of products must be enabled across their scope, such that substantially all products across the claimed range can be made by the skilled person at the priority date without undue burden.  Whilst a patentee may rely upon a principle of general application to demonstrate that it would be reasonably likely that products across the claimed range can be made, such a principle will not save a claim if it can be established that such products cannot in fact be made.  The UKSC also confirmed that 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.  Patentees will therefore need to take care to ensure that the scope of product claims is limited to those products which could be made at the priority date in light of the disclosure of the patent. 
 
Background
 
Regeneron is the proprietor of two patents that claim transgenic mice directed towards producing human antibodies for therapeutic use.  The claimed mice contain so-called ‘reverse chimaeric’ immunoglobulin (i.e. antibody) gene loci, comprising a human variable region and a mouse constant region.  The claims of the patents are to a class of products covering a range of mice containing modified genes of different sizes.  Regeneron commenced infringement proceedings against Kymab in respect of its Kymice transgenic mouse platform.  Kymab sought to revoke the patents on the basis that the methods disclosed in the specification would not have allowed the skilled person to make transgenic mice across the claimed range.
 
At first instance, the High Court held that the claims were invalid on the ground of insufficiency, as none of the methods disclosed in the patents would have worked, and the skilled person would have been unable to make any mouse falling within the claimed range without undue burden.  At the Court of Appeal, Regeneron relied on an alternative method that had not been raised before the High Court.  The Court of Appeal allowed the new argument and accepted that this method would allow mice at the lower end of the claimed range to be made, even though these would be of less interest to those wishing to use transgenic mice to generate therapeutic antibodies.  The Court of Appeal held that, because all mice within the claimed range could be expected to benefit from the advantages conferred by the ‘reverse chimaeric’ loci, namely they would not be “immunologically sick”, then the patents disclosed a principle of general application.  The Court of Appeal therefore held that it was only necessary to enable a single product within the claimed range and that the patents were therefore valid.
 
Supreme Court Judgment
  
The UKSC held (by a majority) that the product claims of the patents were invalid as these claims were not enabled across their scope on the basis of the disclosure in the patents.  In applying the reasoning of the Technical Broads of Appeal of the European Patent Office (in particular the decisions in Unilever/Detergents (T 435/91) and Exxon/Fuel Oils (T 409/91)), the UKSC held that, 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.  As patentees are free to choose how widely to frame the range of products for which they claim protection, they need to ensure that they make no broader claim than is enabled by their disclosure.  The disclosure required of the patentee must therefore be sufficient to enable the skilled person to make substantially all of the types or embodiments of products within the scope of the claim.  However, the UKSC held that this does not mean that the patentee has to demonstrate that every embodiment within the scope of the claim has been tried, tested and proved to have been enabled to be made.  They may instead 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.  However, in doing so, they risk that the supposed general principle will be proved at trial not in fact to enable a significant, relevant, part of the claimed range to be made, as at the priority date.  Importantly, the UKSC made clear that a claim which in substance passes the sufficiency test will not be defeated by dividing the product claim into a range denominated by some wholly irrelevant factor. 
 
Kymab was represented by Powell Gilbert LLP
Please do not hesitate to contact us if you wish to discuss these issues further.

Dr Penny Gilbert
T: 020 3040 8020 | email: penny.gilbert@powellgilbert.com
 
Siddharth Kusumakar
T: 020 3040 8155 | email: siddharth.kusumakar@powellgilbert.com
 
Dr Joel Coles
T: 020 3040 8025 | email: joel.coles@powellgilbert.com