Regeneron Patents Revoked for Claim Breadth

The UK Supreme Court has now issued its judgement in the long running Regeneron v Kymab transgenic mouse cases, finding the Regeneron patents invalid for lack of sufficiency.  

Regeneron Pharmaceuticals Inc sued Kymab Ltd for infringement of their transgenic mouse patents (EP1360287 and EP2264163). The mice covered by the Regeneron patents included a combination of mouse and human DNA, meaning that they produced antibodies that can be used in the treatment of human illnesses without causing immunological sickness in a mouse. The Kymab mice (Kymice) have a similar genetic structure to the Regeneron mice. Kymab’s defence against their alleged infringement was that the Regeneron patents were invalid for lacking sufficiency.  

In this context “sufficient” means that the patent discloses the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. Sufficiency is an essential requirement for UK and EP patents and it is well established that a finding of lack of sufficiency may be justified in the case of excessive claim scope (see Biogen Inc v Medeva plc [1997] RPC 1, often referred to as “Biogen insufficiency”).

Regeneron’s patents contained enough information to enable the skilled person to combine a small amount of human DNA with mouse DNA, leading to a single transgenic mouse. The Court of Appeal felt that this was enough to enable to the skilled person to work the invention and that therefore the requirements of sufficiency were met. Crucially, the Court of Appeal relied on the limited information in the patents providing a “general principle” that could be more widely applied by the skilled person and that it would be unfair to restrict the scope of the Regeneron patents given their “contribution to the art”.

Kymab subsequently appealed to the Supreme Court. The Supreme Court have rejected the Court of Appeal’s “general principle” argument.  Instead, the Supreme Court takes the view that the amount of human DNA to be incorporated is an important factor in determining the diversity of useful antibodies which the mice would produce. Mice containing more human DNA are arguably therapeutically most valuable and it was these mice that could not be made following the teaching in the Regeneron patents. In other words, the Regeneron patents did not include enough information to enable to skilled person to work the invention across its entire scope. The Supreme Court concluded that the Regeneron patents were therefore unduly broad and lacked sufficiency.  

The judgement can be found here. For more information on this and any of the matters raised in this article, please contact Victoria or Maeve.