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Case details

Regeneron Pharmaceuticals Inc (Respondent) v Kymab Ltd (Appellant)

Case ID: UKSC 2018/0131

Case summary


Kymab Ltd ("Kymab") alleges that the relevant patents are invalid for insufficiency because they did not enable the ordinary skilled person to work the claimed invention across the breadth of the claims.


The patents are concerned with biotechnology, and in particular the production of human antibodies using transgenic mice. By the priority date, the potential uses of antibodies (also known as immunoglobulins) for treating human disease had been well recognised, and a number of different antibodies had been developed and approved for such use. The patents describe a technique for making such antibodies.

Regeneron appealed the decision of Henry Carr J that European Patent (UK) No 1 360 287 and its divisional European Patent (UK) No 2 264 163 ("the 287 patent" and "the 163 patent" respectively) are invalid. Kymab cross-appealed against the judge's finding that its various strains of transgenic mice would infringe claims 5 and 6 of the 287 patent and claim 1 of the 163 patent if those patents had not been invalid.

Regeneron’s appeal was allowed by the Court of Appeal. Kymab’s cross-appeal was dismissed.

Judgment appealed

[2018] EWCA Civ 671



Kymab Ltd


Regeneron Pharmaceuticals Inc



Lord Reed, Lord Hodge, Lady Black, Lord Briggs, Lord Sales

Hearing start date

11 Feb 2020

Hearing finish date

12 Feb 2020

Watch hearing
11 Feb 2020 Morning session Afternoon session
12 Feb 2020 Morning session Afternoon session

Judgment details

Judgment date

24 Jun 2020

Neutral citation

[2020] UKSC 27

Watch Judgment summary
24 Jun 2020 Judgment summary