Celltech Chiroscience Ltd v Medimmune Inc: CA 17 Jul 2003

Patents had been granted in the US for human antibodies, and licences issued to the respondent who developed another product themselves. The claimants asserted infringement under the US doctrine of equivalence under which a product or process which does not literally infringe the express terms of a patent claim may nevertheless be found to infringe if there is equivalence between the elements of the accused product or process and the claimed elements of the patented invention. The judge was wrong to find that Celltech was not precluded from relying on the doctrine of equivalence because of an Amendment Estoppel, but was right to find that Celltech was so precluded by an Argument Estoppel. The cross-appeal was allowed and the appeal dismissed save paragraph 1 of the order by which the court dismissed the action.


Lady Justice Arden And Lord Justice Longmore


[2003] EWCA Civ 1008




England and Wales


Appeal fromCelltech Chiroscience Ltd v Medimmune Inc PatC 28-Oct-2002
. .
CitedAMP Incorporated v Hellerman Limited HL 1962
An optional feature of a crimping machine, namely a ‘stop’, was incorporated as an essential feature in an amendment made after acceptance of the patent specification. The question arose whether the amendment was a disclaimer for the purposes of . .

Cited by:

CitedR Griggs Group Ltd and others v Evans and others (No 2) ChD 12-May-2004
A logo had been created for the claimants, by an independent sub-contractor. They sought assignment of their legal title, but, knowing of the claimant’s interest the copyright was assigned to a third party out of the jurisdiction. The claimant . .
Lists of cited by and citing cases may be incomplete.

Intellectual Property

Updated: 06 August 2022; Ref: scu.184615