Tuesday, 16 June 2009

Prior art not a quarry

Tate & Lyle Technology Ltd v Freres [2009] EWHC 1312 (Pat) (16 June 2009) is another patent case, another one in which invalidty is the issue - here, without any infringement issue to worry about, though. Lewison J found the patent in suit - concerning a type of artificial sweetener, maltitol - invalid for want of novelty and also because it was a discovery (and disclosed no patentable invention).

The case related to the validity of a European patent granted to Roquette Freres. The patent, after a great deal of disputation including an opposition and an eventually abandoned appeal, was left with only one claim, which reads:
The use of maltotriitol to modify or control the form of maltitol crystals.

Maltitol is an artificial sweetener made from starch. Tate & Lyle cited several documents, some of which clearly disclosed the use of maltotriitol in the process of manufacture of maltitol and therefore anticipated the claimed invention. With the assistance of expert witnesses, the court satisfied itself that maltotriitol did indeed control and modify the form of crystals formed, so the claimed invention was not novel.
Regardless of whether the prior art processes mentioned the purpose of maltotriitol, the inherent effect would have been to control the form of maltitol crystals that formed. All the patentee had done was discover the effect of a known impurity in affecting crystal formation. There’s nothing new in this reasoning which was summarised by no less an authority than Lord Hoffmann in Synthon BV v Smith Kline Beecham plc:
"…the matter relied upon as prior art must disclose subject-matter which, if performed, would necessarily result in an infringement of the patent. That may be because the prior art discloses the same invention. In that case there will be no question that performance of the earlier invention would infringe and usually it will be apparent to someone who is aware of both the prior art and the patent that it will do so. But patent infringement does not require that one should be aware that one is infringing: "whether or not a person is working [an] … invention is an objective fact independent of what he knows or thinks about what he is doing": Merrell Dow Pharmaceuticals Inc v H N Norton & Co Ltd [1996] R.P.C. 76 , 90. It follows that, whether or not it would be apparent to anyone at the time, whenever subject-matter described in the prior disclosure is capable of being performed and is such that, if performed, it must result in the patent being infringed, the disclosure condition is satisfied. The flag has been planted, even though the author or maker of the prior art was not aware that he was doing so."

Having applied this approach to the various documents cited, the court found that the patent was anticipated by no fewer than five of them. Tate & Lyle also suggested that the claim was invalid because the contribution was a mere discovery, excluded from patentability under section 1(2). The claim merely informed the reader that maltotriitol, which was a known impurity in the manufacture of maltitol, had the effect of changing the formation of crystals, so all the patent contributed was the discovery that the crystal changing was caused by maltotriitol's presence. As Mr Justice Lewison expressed it:
"In Molière's play Le Bourgeois Gentilhomme, Monsieur Jourdain asks something to be written in neither verse nor prose. A philosophy master says to him, "Sir, there is no other way to express oneself than with prose or verse". Jourdain replies, "By my faith! For more than forty years I have been speaking prose without knowing anything about it, and I am much obliged to you for having taught me that." That is this case. The industry has been using maltotriitol to control or determine crystal habit without knowing it. What is left of the patent as granted is no more than a discovery as such."
A cautionary word about how to use the prior art is also worth quoting: the judge was unimpressed by an expert witness who "treated the cited prior art as a quarry from which the occasional nugget could be extracted, with knowledge of the problem to be solved, rather than approaching the teaching of each of the pieces of prior art on its own terms and seeing where that led him."

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