According to UK and European patent law, an invention in a patent claim is not new if what is claimed has been made available to the public before the priority date of the application. There may, for example, be a clear statement in a prior published document that describes a chemical compound and how to make it, which would make a claim to that particular compound not novel. If, however, there is some doubt about whether the actual form of compound claimed would result from the described process, it needs to be determined whether following the process would inevitably arrive at the claimed compound.
This was the situation in Leo Pharma v Sandoz EWCA Civ 1188, which was decided by Lords Justice Jacob and Patten yesterday (17 November), on appeal from Floyd J's decision in the High Court earlier this year ( EWHC 996 (Pat)). The case related to the chemical compound calcipotriol, a vitamin D analogue used for the treatment of skin conditions. Sandoz had been attempting to invalidate Leo's patent EP0679154 for calcipotriol monohydrate, which the patent claimed was "a new crystalline form of calcipotriol - with superior technical properties e.g. in the manufacture of crystal suspension formulations, and with superior stability properties". Whether these particular advantages were true or not was not in issue. What was in issue (among other things) was whether this crystalline form would be the inevitable result of following the instructions for making calcipotriol found in a previously published document, WO8700834.
Sandoz's task seemed therefore to be straightforward (at least to this untrained Kat): simply follow the instructions in the document and show that calcipotriol monohydrate would result. Unfortunately, this is not what Sandoz did. Instead of using the starting materials that were specified in the document, Sandoz used a material supplied by Teva that was developed only after the document was published, and instead of ensuring a seed-free environment Sandoz seeded the reaction with monohydrate crystals. These differences were sufficient to at least sow some seeds of doubt as to whether, if the instructions had been followed to the letter, the claimed compound would actually result.
"One would have thought that the task of proving this would be undertaken in a straightforward way. I set it out when at first instance in Synthon's Patent  RPC 33 at :
'Given the "inevitable result" branch of the law of anticipation (see below) one might have thought (a) that a team of ordinary ability might have been engaged (one is concerned with the ordinary skilled man or team, not world champions) and (b) that the team concerned would simply have been given the Synthon patent and asked to carry out its teaching to make paroxetine mesylate crystals.'
Experience shows that some parties attacking patents simply do not follow this straightforward path. Instead they depart from the prior art. Then, as here, an argument starts about the nature of the departure and whether it mattered. For the life of me I cannot understand why they do this. It inflates the costs and time, and seldom if ever does the defendant any good" (paragraphs 17-18).Sandoz's attempts at having the finding of lack of anticipation overturned therefore failed, and the appeal was dismissed.