Flags and Signposts: the Tortuous Markings between Disclosure and Enablement

What happens when two people independently arrive at the same invention and both seek patent protection? In the UK, as in Europe, the answer is that only the person who first files is entitled to a patent, notwithstanding the delay between the filing of the application and the publication of its subject-matter. If you file a patent application and later find that someone else has filed an application before you, which is published only after your application or priority date, it counts as prior art, but for novelty purposes only, against your application.

But what if the teaching of the earlier application does not quite work? Synthon v. SKB is a case on the borderline – the patent concerned was held valid at first instance, the decision was reversed by the Court of Appeal, then the appeal itself was reversed by the House of Lords, the highest UK court.

 

Synthon BV v. SmithKline Beecham Plc (No.2) [2006] R.P.C. 10

The issue here related to paroxetine, which is used in the lucrative fields of treating depression and related disorders, and is marketed under the trade names Paxil™ or Seroxat™. Both parties to this dispute discovered a new salt of paroxetine, paroxetine methanesulfonate (“PMS”) at about the same time. PMS is more suitable for pharmaceutical uses than previously known salts of the compound so, understandably, both were keen to obtain patent protection.

Synthon were the first to apply, filing a PCT application on 10 June 1997. Smithkline Beecham (“SKB”) took their time, filing on 6 October, 1998, which became the priority date for the UK patent in suit. Synthon’s application was published two months later, on 17 December, 1998.

SKB’s patent claimed a particular crystalline form of PMS, reciting specific infra-red radiation and X-ray diffraction spectrums. Synthon’s application gave various properties of their PMS crystal, including its infra-red spectrum and included instructions on how to make the crystal. Synthon commenced a revocation action against SKB’s patent, citing their published PCT application on the ground of lack of novelty. The matter boiled down to the issue of novelty, and under what conditions a statement can be considered to form part of the state of the art.

 

Problems with Synthon’s Disclosure

Possibly because Synthon were quick to file, it turned out that there were some problems with their description. The infra-red spectrum given in their example differed from that specified in SKB’s claim. In preparation for the trial, Synthon employed the services of an expert witness and provided him with a solution from which, according to their patent description, crystalline PMS could be formed. They provided him with the instructions of the patent description for forming the crystal and sent him off to do so. This was a complete failure. Eventually, the expert was able, by a completely different method, to produce crystals which did not have the infra-red spectrum predicted by the application but were the same as those specified in SKB’s claim. Synthon later discovered that the infra-red spectrum disclosed in their application was wrong, due to a laboratory error.

In their patent application Synthon had merely stated that they had discovered PMS crystals and that they could be made. The question then before the House of Lords was: is this enough to destroy the novelty of SKB’s claim, even though Synthon erred in describing both the properties of the crystal and the method of manufacturing it?

Lord Hoffman, who delivered the unanimous judgement of the court, stressed that there are two requirements that have to be met. Firstly, did their application disclose the invention of the claim of SKB’s patent - i.e. was there “disclosure”? Secondly, would the ordinary skilled man be able to perform the disclosed invention if he attempted to do so by using the disclosed matter and common general knowledge - i.e. was the disclosure “enabling”? These two requirements for a disclosure to be novelty destroying are well established in UK patent law and have resulted in the widespread use of the shorthand “enabling disclosure” (the derivation of which is discussed by Lord Walker in an assenting judgement).

Lord Hoffman quoted the now famous case of General Tire and Rubber Co v. Firestone Tyre and Rubber Co Ltd [1972] RPC 457 where the test for novelty-destroying disclosure is stated in these terms;

To anticipate the patentee’s claim the prior publication must contain clear and unmistakable directions to do what the patentee claims to have invented. . . . A signpost, however clear, upon the road to the patentee’s invention will not suffice. The prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee.

Lord Hoffman also cited, with approval, a number of EPO Board of Appeal decisions and summarised the requirement in a sentence: “the matter relied upon as prior art must disclose subject-matter which, if performed, would necessarily result in an infringement of the patent”. So the prior art relied on must not only result in something that falls in the scope of the claim (disclosure) but must describe how to arrive at this in sufficient detail that it can be carried out by a person skilled in the art (enablement).

The previous House of Lords case Merrell Dow Pharmaceuticals v. H N Norton & Co Ltd [1996] RPC 76 was also referred to in the judgement. In this case a claim to a particular compound was found to be anticipated because that compound had been produced in the livers of patients who had taken a medicine. It was irrelevant that neither the patients nor anyone else knew that they were producing the claimed compound.

 

Synthon had Planted the Flag

So, Synthon had “planted the flag” by stating that they had discovered PMS crystals – there was disclosure. Lord Hoffman accepted the trial judge’s finding that PMS is monomorphic (having only one crystal structure). It did not matter therefore that Synthon made a mistake in describing the spectrum of their crystal. A person skilled in the art setting out to make crystalline PMS would arrive at the subject-matter of SKB’s claim.

The trial judge also found that, despite the errors described in the method of producing the crystal, a skilled person would be able to produce the crystal in a reasonable time. Lord Hoffman accepted this, citing authority indicating that a certain amount of signposting, or trial and error, is allowed when endeavouring to arrive at the subject-matter. There was therefore “enablement”.

The appeal was therefore allowed and the patent found invalid for lack of novelty.

 

Comment

The trial judge (Mr. Justice Jacob, as he then was) spent a considerable part of his judgment considering the rationale of avoiding double patenting as underlying the novelty-only approach to invalidity over unpublished prior filed patent applications – giving lack of novelty a “purposive” approach to avoiding double patenting. Lord Justice Aldous also considered these points in his appeal judgement, but considered that the public policy had been implemented by a strict novelty approach, which overrode issues of double patenting..

Lord Hoffmann put to bed any such speculations as to how policy considerations of double patenting should influence the outcome of a particular case. The European law is clear: you are not entitled to claim something which I describe in a published patent application, filed in the same country before you.