UK: Test for novelty of patents reconsidered by House of Lords

Last Updated: 15 November 2005
Article by Nick Beckett

The House of Lords has determined that there are two legal requirements for the test of novelty of patents: "prior disclosure" and "enablement". Whilst these concepts have previously been joined together in the concept of an "enabling disclosure", the House of Lords stated that it is important that the two concepts be kept distinct. The House of Lords came to this conclusion in its decision in Synthon BV v Smithkline Beecham plc [2005] UKHL 59. Allowing Synthon's appeal, the House of Lords restored the trial judge's finding of invalidity for lack of novelty for a patent relating to paroxetine, a compound used to treat depression and related disorders.

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The House of Lords last month handed down its decision in Synthon BV v Smithkline Beecham plc [2005] UKHL 59 and has allowed Synthon's appeal, restoring the trial judge's finding of invalidity for lack of novelty. Of significant interest are the House of Lord's considerations of the legal requirements for the test of novelty. In particular, the House of Lords determined that there are two requirements for anticipation: a "prior disclosure" and "enablement". Whilst these concepts have previously been joined together in the concept of an "enabling disclosure", the House of Lords stated that it is important that the two concepts be kept distinct.


Paroxetine is a compound used to treat depression and related disorders. It has for some time been marketed in the form of its hydrochloride hemihydrate salt under the name Paxil or Seroxat. These proceedings arise out of the more or less simultaneous discovery in about 1997 by the claimant Synthon BV, a Dutch pharmaceutical company, and Smithkline Beecham plc ("Beecham"), a UK pharmaceutical company, that a different paroxetine salt, paroxetine methanesulfonate ("PMS"), has properties which make it more suitable for pharmaceutical use.

The disputed patent covered a crystalline form of PMS – a form of paroxetine, which is the active ingredient in SmithKline Beecham's antidepressent Seroxat. Synthon challenged this patent in 2001 as being anticipated by its own, unpublished application.

Both Synthon and Beecham discovered this invention at a similar time. Synthon filed an application under the Patent Cooperation Treaty in 1997 for a broad class of compounds, including PMS, and described how to make PMS in crystalline form. Beecham filed a UK priority application in 1998, before Synthon's application was published, claiming a particular form of crystalline PMS (by reference to its IR and XRD peaks). Beecham's UK patent, deriving from its priority application, was published in 2000.

Synthon submitted that Beecham's invention was not new, and that its own application disclosed the same invention as patented by Beecham, and that the ordinary skilled man was able to produce the invention based on the disclosed information and his general knowledge. Synthon convinced the High Court, which in 2002 declared Beecham's patent invalid. But in 2003 the Court of Appeal overturned the ruling, which Synthon in turn appealed to the House of Lords.


Synthon accepted that the crystalline form of PMS had not been made "available to the public" before the priority date and therefore did not rely on Section 2(2) of the Patents Act 1977. They relied on Section 2(3), claiming that it was deemed to be part of the state of art by virtue of having been disclosed in Synthon's patent.

The two issues were whether:

  1. Synthon's application disclosed the invention which had been claimed in the patent (the disclosure issue)
  2. 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 (the enablement issue).


Appeal allowed.

Lord Hoffmann stated that disclosure and enablement are distinct concepts, each with its own function and rules and criticised the Court of Appeal for intermingling the two concepts.

The Disclosure Issue

Lord Hoffmann said that the matter relied upon as prior art must disclose subject matter which, if performed, would necessarily result in an infringement of the patent. Infringement must not merely be a possible or even likely consequence of performing the invention disclosed – it must be necessarily entailed. It will usually 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 (Merrell Dow v Norton [1996] RPC 76, 90). Whenever subject matter described in the prior disclosure is capable of being performed and is such that, if performed, it must inevitably result in the patent being infringed, the disclosure condition is satisfied. Lord Hoffmann stated that "The flag has been planted, even though the author or maker of the prior art was not aware that he was doing so".

Lord Hoffman continued to say that it is this requirement that performance of an invention disclosed in the prior art must necessarily infringe the patent which distinguishes novelty from obviousness. The Synthon application was deemed to form part of the state of the art for the purposes of novelty (section 2(3)) but not for the purpose of obviousness (section 3). The application disclosed an invention which, if performed, would infringe Beecham's patent. The subject matter described in the patent was crystalline PMS and a skilled person who performed that invention would inevitably infringe it, even though he might on reading the patent believe he would not. There is only one crystalline form of PMS and any crystals would invariably have the characteristics described in the patent. The IR and XRD peaks identified were therefore superfluous.

The Enablement Issue

Lord Hoffmann said that "enablement" means that the ordinary skilled person would be able to perform the invention which satisfies the requirement of disclosure. This requirement applies whether the disclosure is in matter which forms part of the state of the art by virtue of section 2(2) or, as in this case, section 2(3). In this case, the disclosure in the application was PMS and there was no dispute that it would have enabled the skilled person to make PMS. The pertinent issue was factual and related to whether the skilled person would have been able to crystallise the PMS. Synthon specified in their main example a solvent that proved unsuitable for crystallisation. Despite this the judge at first instance found that the skilled man would have tried one of the other solvents mentioned in the application or which formed part of his common general knowledge and would have been able to make PMS crystals within a reasonable time. Lord Hoffmann said this was a finding of fact by a very experienced judge with which an appellate court should be reluctant to interfere. On that basis, he held that the Synthon patent application did satisfy the enablement test and, as a result, the Beecham patent was invalid.


The case is noteworthy for a number of reasons:

  • whereas previously, it has been common practice to refer to the concept of "enabling disclosures", going forward it will be necessary to deal with the concepts of "disclosure" and "enablement" separately. Lord Hoffmann states that it is very important to keep these concepts distinct and it is likely that this will result in less confusion regarding the law of anticipation going forward.
  • in terms of the concept of the "disclosure", previously it has been common to consider that there are two forms of anticipatory disclosure - a disclosure of the patented invention itself and a disclosure of an invention which, if performed, would necessarily infringe the patented invention. Lord Hoffmann has clarified that, in fact, these are aspects of a single principle, namely that the anticipation requires prior disclosure of subject matter which, when performed, must necessarily infringe the patented invention.
  • with regards to the concept of "enablement", Lord Hoffmann has confirmed that, as at the EPO, the test of enablement is the same whether it is being considered for the purpose of anticipation or insufficiency - a point on which the Court of Appeal did not comment.
  • the role of the skilled reader and reliance on common general knowledge is different in respect of the issue of "disclosure" and the issue of "enablement". In the former case the skilled reader will rely upon common general knowledge to assist in his construction of the disclosure (along the lines of that discussed by the House of Lords in Kirin-Amgen). In the latter case, the common general knowledge will be used by the skilled reader to assess whether he is able to work the invention.
  • trial and error experimentation will only be possible at the "enablement" stage. The trials that may be conducted will be a question of fact involving consideration, of the application of standards, the problem in hand, the assistance provided by the disclosure itself and the extent of common general knowledge.

This article was written for Law-Now, CMS Cameron McKenna's free online information service. To register for Law-Now, please go to

Law-Now information is for general purposes and guidance only. The information and opinions expressed in all Law-Now articles are not necessarily comprehensive and do not purport to give professional or legal advice. All Law-Now information relates to circumstances prevailing at the date of its original publication and may not have been updated to reflect subsequent developments.

The original publication date for this article was 11/11/2005.

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