Tate & Lyle Technology Ltd v Freres

A patent claim directed to the use of an impurity to control crystal habit is construed according to its substance. “Control” may include monitoring, checking or maintaining a satisfactory level; active adjustment is unnecessary. A prior disclosure anticipates a claim where carrying it out necessarily infringes, even if the earlier author was unaware of the invention. A claim which merely states a newly discovered property, without claiming a practical product or process exploiting it, is excluded as a discovery as such. Obviousness requires the structured Pozzoli analysis and a fair expectation of success, not merely an ability to try the investigation.

Roquette Frères owned a patent concerning maltitol crystals. Following opposition proceedings, only a claim directed to the use of maltotriitol to modify or control the form of maltitol crystals remained. Tate & Lyle sought revocation on grounds of lack of novelty, excluded subject matter and obviousness.

The court had to construe the scope of “use”, “modify or control” and “form”, and determine whether the cited prior art inevitably practised the claimed use. It also had to decide whether the claim amounted only to a discovery and whether the claimed subject matter was obvious.

1. Construction. The claim concerned the use of maltotriitol to modify or control maltitol crystal habit. “Modify” meant to change, but “control” had a broader meaning. It included monitoring, inspecting or checking the maltotriitol content, without necessarily changing it. The claim could therefore be infringed by a process which consistently produced bipyramidal crystals, prismatic crystals or a mixture of both. Active adjustment was unnecessary. The control could also be indirect, by adjusting maltotriose before hydrogenation. [34]–[41]
2. Anticipation. Applying the approach stated in Synthon BV v Smith Kline Beecham plc, the prior art had to disclose subject matter which, if performed, necessarily resulted in infringement. The relevant question was objective and did not depend on the earlier user knowing of the invention. Hirao, Boursier, Devos, Nimi and Magara each necessarily or inevitably practised the claimed use on the evidence. The claim was therefore anticipated by each of those disclosures. Ribadeau-Dumas added nothing material, while Caboche did not necessarily infringe. [52]–[73]
3. Discovery as such. Section 1 (2) of the Patents Act 1977 excluded a discovery as such. Applying Kirin-Amgen Inc v Hoechst Marion Roussel Ltd, an invention had to be a practical product or process rather than information about the natural world. The remaining claim merely identified the property of maltotriitol which the industry had already been using unknowingly. The words “the use of” did not convert that discovery into a patentable invention. [74]–[76]
4. Obviousness. The court applied the structured approach in Pozzoli Spa v BDMO SA. Although the skilled person might have investigated crystal habit and would have had a fair expectation that some investigation would succeed, there was no fair expectation that maltotriitol would be identified as the determining impurity. The claim was not shown to be obvious over common general knowledge or any individual citation. [77]–[86]
5. The patent was invalid for lack of novelty and because it claimed an unpatentable discovery. The patent was revoked. [87]