May and Baker Ltd and others v Boots Pure Drug Company Ltd: HL 9 Feb 1950

A beneficial therapeutic effect was said to be of the essence of the claim. The House considered whether in defending the validity of a patent, the patentee might be allowed an application to amend the patent specification. The patentee had not been so allowed in this case.
Held: The proposed amendment will make the invention claimed substantially different from that claimed before amendment, and was not permissible.
Lord Simonds, Lord Normand, Lord Morton of Henryton, Lord MacDermott, Lord Reid
[1950] UKHL 1, (1950) 67 RPC 23
Bailii
Patents and Designs Act 1946 22
England and Wales
Cited by:
CitedRegeneron Pharmaceuticals Inc v Kymab Ltd SC 24-Jun-2020
SC 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 . .

These lists may be incomplete.
Updated: 21 June 2021; Ref: scu.246085