House of Lords clarifies novelty test: Synthon BV v Smithkline Beecham plc

Patent owners have won new powers to enforce their rights in the UK after a House of Lords ruling clarified when an invention can be considered new and patentable.

After a near four-year dispute, the House of Lords reinstated an earlier High Court ruling that SmithKline Beecham's (SB) patent had been anticipated by a Synthon invention and was therefore invalid, after the Court of Appeal had initially overturned the ruling.

The ruling updates the meaning of disclosure and enablement, and clarifies what constitutes a patentable and enforceable invention.

The disputed patent covered a crystalline form of paroxetine methanesulfonate (PMS), a known version of paroxetine, paroxetine being the active ingredient in an antidepressant. Synthon challenged this patent in 2001 for being anticipated by its own, unpublished, application.

Both Synthon and SB had discovered at a similar time that PMS has properties which make it more suitable for pharmaceutical use than paroxetine. Synthon had filed a PCT application for this in 1997 and SB filed a UK application in 1998, before Synthon's application was published. SB's UK patent was published in 2000, and Synthon applied to revoke it.

Example 1 of Synthon's specification describes how to make PMS in crystalline form, with the data for the crystals being given in Table 1. A note after Table 1 draws attention to the fact that the compounds may be polymorphic (as opposed to monomorphic) and exist in other crystalline forms.

Claim 1 of the SB patent was limited to a particular form of crystalline PMS, defining the crystal by reference to specific peaks observed during analysis (infra-red (IR) spectra and x-ray crystal diffraction), thus identifying a particular crystalline form of PMS.

If, as Synthon's specification said was possible, PMS turned out to be polymorphic, no other forms of crystal were claimed by SB. However, the data given in claim 1 is different to that given in Table 1 of Synthon's specification. A person skilled in the art, on simply reading both documents, would therefore think that they identified different polymorphs.

Synthon, relying on Section 2(3) of the Patents Act for their arguments, were claiming that the crystalline form of PMS described in claim 1 was not new as it had been disclosed in their own application.

In order to prove their case, Synthon had to satisfy the judge that their application disclosed the invention which had been patented as claim 1 (disclosure), and also that an ordinary skilled man would be able to perform the disclosed invention if he attempted to do so by using the disclosed matter and common general knowledge (enablement).

For the disclosure, Synthon relied upon the fact that their application disclosed the existence of PMS in crystalline form. However, the differences in the IR data suggested that it was not the same crystalline form as claimed in the patent. Synthon nevertheless went ahead with experiments designed to show that they satisfied the requirement of enablement. These experiments, based on those in Synthon's application, failed to produce any crystals, although the scientists did manage to produce crystals using other methods not disclosed in Synthon's application. These crystals, however, did not have the IR spectrum predicted by Synthon in Table 1. Instead, they had the spectrum described in claim 1 of SB's patent.

At trial, Synthon showed that the IR spectrum in Table 1 of their application was the result of a mistaken reading in their own laboratory, and that PMS was in fact monomorphic, as shown by their new data. Thus, any PMS crystal produced would have the characteristics described in SB's patent. This was accepted by the judge, who found that a disclosure of a crystalline form of PMS necessarily meant that it would be the form described in SB's patent, even though a person who had read the patent and set out to make the form described in the application might have thought he was making something different.

Secondly, on enablement, Synthon claimed that although the method described in the application did not produce seeding crystals, that did not mean that the ordinary skilled man would not be able to crystallise PMS. The trouble with the described method turned out to be that it had used an unsuitable solvent. However, the ordinary skilled man, if not confined to a particular solvent, would try another. Crystallisation was an art rather than an exact science and commonly involved some routine trial and error before results were achieved. This argument was also accepted by the judge, who found that the reader of the application, seeking to crystallise PMS, would be able to overcome any problems within a reasonable time, as the scientists had managed to do. The crystals made would then necessarily be the crystals described in SB's patent.

It was therefore held that the matter contained in the application did disclose the existence of the very product which was the subject of SB's patent and that the making of that product was enabled. The patent was invalid and thus revoked.

This judgement was overturned by the Court of Appeal, but reinstated by the House of Lords.

It was stated that it was essential that prior disclosure and enablement were looked at separately to decide whether a patent was anticipated, and that they must be considered as distinct concepts, each of which has to be satisfied and each of which has its own rules.

It was said that the role of the skilled person differed in both instances. To put disclosure to the test, it was important to see if the skilled person could understand the written description in prior art based on his general knowledge. For enablement, the question was whether the skilled person could perform the invention based on the disclosed information. The House of Lords held that both requirements were fulfilled, and the patent was thus invalid.

Importantly for patent owners, the case clarifies that the disclosed information in patent applications does not have to be absolutely accurate for the patent to be enforceable.

For more information, download the full judgement: http://www.parliament.the-stationery-office.co.uk/pa/ld200506/ldjudgmt/jd051020/synth-1.htm

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