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The House of Lords allowed Synthon's appeal from the Court of Appeal and held that Smithkline Beecham's patent for a crystalline form of paroxetine methanesulfonate (PMS), a pharmaceutical compound used to treat depression, was invalid on the basis that it was anticipated by information in a patent application filed earlier by Synthon. The House of Lords unanimously reversed the Court of Appeal's decision on the basis that it had confused the separate concepts of disclosure and enablement required under the test for novelty and, as a result, had wrongly interfered with the first instance judge's finding of invalidity. Lord Hoffmann gave the leading judgment and emphasised that it is very important to keep in mind that disclosure and enablement are distinct concepts, each of which has to be satisfied and each of which has its own rules.
DISCLOSURE
In relation to the first requirement of disclosure, the House of Lords approved the long-standing test that this requirement is satisfied if the prior disclosure, as understood by an ordinary skilled person at the time of disclosure, were to be performed, it would necessarily result in an infringement of the patent in suit. For this requirement, no degree of experimentation on the part of the skilled person is to be assumed. Synthon's application had disclosed the existence of the PMS compound claimed in Smithkline Beecham's patent, but Synthon's IR (infrared) spectrum identifying the crystalline form of PMS was incorrectly recorded and did not match the crystalline form claimed in Smithkline Beecham's patent. The first instance judge had accepted evidence that there is only one possible crystalline form of PMS. In applying the test for disclosure to the facts of the case, the House of Lords held that there was prior disclosure because an ordinary skilled person performing Synthon's invention would inevitably infringe Smithkline Beecham's patent, even if that person believed that a different product had been described in Synthon's application.
ENABLEMENT
In relation to the second requirement of enablement, the House of Lords held that the test was whether an ordinary skilled person would be able to perform a disclosed invention using the disclosed information and that person's common general knowledge. The House of Lords confirmed that the concept of enablement in the test for novelty is the same as that used in other areas of patent law, such as the requirement that there be sufficient disclosure of an invention in a patent specification. To satisfy the requirement for enablement, the House of Lords held that some degree of trial and error experimentation to get an invention to work can be assumed. The main experimental example in Synthon's application referred to an unsuitable solvent and, in evidence before the first instance judge, strict adherence to the method described in this example did not produce crystalline PMS at all. There was no dispute that the disclosure in Synthon's application would have enabled an ordinary skilled person to make PMS, but the issue was whether that skilled person would be able to crystallise PMS. This was a question of fact and the first instance judge found that an ordinary skilled person would have
tried other solvents and would have been able to make PMS crystals within a reasonable time period. The House of Lords held that this was a finding of fact by a very experienced patent judge with which an appellate court should be reluctant to interfere.
This decision provides welcome clarification on the distinction between the concepts of disclosure and enablement when applying the test of novelty. In particular, it is clear that the information and methods disclosed in a patent application do not need to be absolutely accurate. However, expert advice should be sought to ensure that an appropriate balance is struck between the need for early filing of a patent application and the need for disclosures to be of sufficient detail to meet the requirement for enablement.
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