In Leo Pharma (a/s Leo Laboratories Ltd) v Sandoz Ltd  EWHC 996 (Pat) (15 May 2009) the defendant admitted that it had infringed the patent in suit but contended that the patent was invalid for lack of novelty and obviousness. The case was decided on its facts rather than on the law.
“(1) There are two requirements for anticipation which it is important to keep separate,(a) disclosure and(b) enablement;
(2) So far as disclosure is concerned, the prior art must disclose subject-matter which, if performed, would necessarily result in an infringement of the patent.”
In Leo Pharma the relevant subject-matter contained in the prior art document was said to disclose the invention not because it described the product in terms (which it did not), but because it was said that carrying out the disclosure would inevitably produce that product. The judge disagreed. Experimental and other evidence did not support the claim that the patented product would be the inevitable result.
“(1) (a) Identify the notional “person skilled in the art”
(b) Identify the relevant common general knowledge of that person;
(2) Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;
(3) Identify what, if any, differences exist between the matter cited as forming part of the “state of the art” and the inventive concept of the claim or the claim as construed;
(4) Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?””
The defendant put its case on obviousness in several ways none of which appealed to the judge. The attack on validity having failed, the judge found for the claimant.