The House of Lords clarifies the UK approach to obviousness

In its decision in Conor Medsystems Inc v Angiotech Pharmaceuticals Inc¹, the House of Lords ("HL") discussed the approach the UK courts should adopt when determining whether a patent is obvious – The courts should look to the patent claims and not the specification to identify the inventive step and determine obviousness. Providing the specification passes the 'threshold test' of disclosing enough to make the invention plausible, it need not prove that the claimed invention will work. Cases where the 'obvious to try' test is appropriate require a fair expectation of success. Such expectation is to be assessed on the relevant circumstances.

Business impact

Although it remains to be seen how this decision will settle down into the judgments of the lower courts, it seems it may represent a lowering of the threshold of what is inventive from the approaches taken by Pumfrey J and Laddie J in recent years.

Background

Art.52(1) and Art.56 of the European Patent Convention 1973, as implemented by s 1(1)(b) and s.3 Patents Act 1977, provide that an invention shall be taken to involve a patentable inventive step if it is not obvious to a person skilled in the art, having regard to any matter which forms part of the state of the art. The established approach to obviousness is set out in Windsurfing². However, this approach still leaves the essential question of "what is obvious?". The courts have deliberately avoided trying to define obviousness. For example in Norton  Healthcare v Beecham Group³ the CA stated that 'No formula should be substituted for the words of the statute. In every case, the Court has to weigh up the evidence and decide whether the invention was obvious. This is the statutory task.'  However, inevitably, the UK case law has developed a number of tests to assist in determining whether a patent is obvious. One such test applied in appropriate circumstances is the "obvious-to-try" test.

For a number of years, patentees, particularly in the originator pharmaceutical industry have complained that potential infringers have found it too easy to invalidate their patents in the UK. This is because, they say, the UK courts have been setting the bar of what is inventive too high. The appeal to the HL was therefore an opportunity for them to restate the correct approach that the UK court should take to identify the inventive step and determine obviousness in cases where the "obvious-to-try" test is applicable.

Facts

Conor Medsystems concerns stent technology used in the treatment of angiogenesis, the growth of blood vessels causing arteries to become constricted or "stenosed", which can result in angina and heart failure. Stents are small, tubular wire cages, which are pushed into the blocked artery to hold it open. A deficiency of existing stents was that, whilst they could open up such blockages, they could not prevent the growth of blood vessels into the stent itself, further closing the arteries, so-called restenosis.

Angiotech's patent claimed a stent coated in taxol, an 'anti-replicate' drug, for treating or preventing restenosis. Importantly, taxol was one of a number of known anti-replicates at the priority date of the patent and the patent did not contain any proof that the stent coated with taxol would actually work to treat restenosis. Conor sought revocation of the patent on the basis that it was obvious in the light of prior art which disclosed a drug-eluting stent for local delivery of 'anti-replicate' drugs which might reduce restenosis. At first instance Pumfrey J agreed with Conor and revoked the patent as obvious. This decision was upheld on appeal. Jacob LJ stated that 'Just to name one "other" anti-replicate which, on the information given in the patent is no more and no less likely to be found to work in practice is not to make an invention.'

Angiotech were given leave to appeal to the HL. Concurrent proceedings before the District Court of The Hague found the patent to be valid and the parties reached a settlement in relation to the UK proceedings. However, because a patent confers proprietary rights in rem and the validity of a patent cannot be established simply by a judgment in default of opposition, the HL invited the Comptroller General to stand in place of the respondent and present the arguments against the validity of the patent. There were two key issues on which the HL focused:


The patent specification, inventive step and obviousness

This first issue was particular to the drafting of the patent at issue. The Appellants argued that inventiveness lay in the claim that the coated stent would have the property of treating restenosis. However, Counsel on behalf of the Respondent sought to 'water down the claimed invention by reference to what he said were inadequacies in the specification'. He argued that the patent did not show that taxol would actually work in reducing restenosis and was therefore nothing more than an idea that taxol might work. So on the basis that the patent taught no more than that taxol was worth trying, he submitted that it added nothing to existing knowledge.

Whilst the HL confirmed that a patent will not be granted for an idea which is mere speculation, unsupported by anything disclosed in the specification, this was not such a case. In the HL's view, the specification did support a claim for a taxol coated stent to treat or prevent restenosis. Although the specification did not show that taxol would actually reduce restenosis, there is no requirement in patent law that the specification must explain that the invention would work. The argument put forward on behalf of the respondent was an illegitimate amalgam of the requirements of inventiveness and either insufficiency or support or both. If a specification passes the threshold test of disclosing enough to make the invention plausible, the question of obviousness should not be subject to a different test according to the amount of evidence the patentee presents to justify a conclusion that his patent will work. Failing to appreciate this had led the Court of Appeal to assess obviousness incorrectly. The inventive step should be identified by reference to the patent claims. Therefore, in this case, the correct question was whether it was obvious to use a taxol-coated stent to treat or prevent restenosis not whether it was obvious that taxol (among other products) might have the effect of treating restenosis and was therefore worth testing.

Obvious-to-try

Having decided this, the second issue was of apparently broader application. What is the correct approach to the obvious-to-try test? At first instance Pumfrey J assessed obviousness on the basis of whether the skilled person would incorporate taxol in a drug-eluting stent without any expectation of success. In the CA, Jacob LJ restated the test set out in his earlier decision in St Gobain⁴ : that the 'obvious to try test really only works where it is more-or-less self evident that what is being tested ought to work'. He went on to decide that on the facts of the case it was not appropriate to apply this test because, as discussed above, he thought the patent disclosed no such success. The HL had to therefore decide where the correct approach should lie. They stated that the correct formulation was posed, but not applied, by Pumfrey J: 'is the patent vulnerable only if it can be shown that the skilled person would have an expectation of success sufficient to induce him to incorporate taxol in a drug-eluting stent…?' If he had done so, he would have found the patent to be non-obvious. The HL then added detail to this by apparently confirming that the correct approach under the authorities was to say that 'obvious to try was useful only in a case in which there was a fair expectation of success'. How much expectation would be needed depended on the particular facts of the case. In this respect Hoffman LJ endorsed the statement of Kitchin J in Generics (UK) Ltd v H Lundbeck A/S⁵ :

'The question of obviousness must be considered on the facts of each case. The court must consider the weight to be attached to any particular factor in the light of all the relevant circumstances. These may include such matters as the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectation of success.'

In supporting Hoffman LJ's leading judgment, Walker LJ noted the following academic observations by Sir Hugh Laddie that 'what makes something worth trying is the outcome of a simple risk to reward calculation….the more commercially attractive the solution…the harder it will be to avoid an obviousness attack. In those circumstances a solution which is quite low down a list of alternatives, all of which are more or less worth trying, will fail for obviousness; a consequence which is consistent with the decision in Brugger v Medic-Aid.' Walker LJ then noted, as Laddie J had said, that as technology advances rapidly, this is a serious and growing problem. In doing so it is not clear if he is criticising this result, as exemplified in Brugger v Medic-Aid, but it is perhaps noteworthy that it seems at odds with the basis on which the patent in Conor Medystems was found non-obvious - which is that the prior art left one in no better position than knowing that the solution may lie somewhere in the large number of drugs which could be tried.

Interestingly, as a practical point, Walker LJ also noted that the difficulties faced by the Applicants in litigating this case resulted from the unfocused nature of their patent. In an attempt to cover as much ground as possible the specification contained so much extraneous matter that its teaching was nearly lost.

Conclusion

The House of Lords has clarified that the court must look to the claim of a patent to identify the inventive step. Provided the claim passes the 'threshold test' of plausibility, the information disclosed in the patent specification is not relevant to questions of obviousness, only sufficiency. Will patentees find it easier to obtain and defend patents on the basis of their "inventiveness"? The endorsement by the HL of the idea that something can only be obvious to try in the fair expectation of success, where such expectation is to be assessed on all the factors, does appear to be a move away from the more hard line approach adopted by Pumfrey J that expectation of success is not relevant⁶. It also seems to move away from the approach of Laddie J, discussed by Walker LJ⁷, that the number of routes that may be tried before coming to an invention can be irrelevant if they are all obvious to try. Indeed, maybe this is what Lord Neuberger means when he states that "...the decision represents a significant development in United Kingdom patent law, and we are differing from the views of highly experienced Judges in that field…" This is an important authority, but how it will be interpreted and applied in UK courts will only be seen in the coming months and years.


_____________________________________________________________

^{1  [2008] UKHL 49
2}  Windsurfing International Inc v Tabur Marine (Great Britain) Ltd [1985] RPC as modified by Pozzoli v BDMO [2007] EWCA Civ 588
³  [1997] F.S.R. 81
⁴  St  Gobain v Fusion Provida [2005] EWCA Civ 177
⁵ [2007] RPC 32, Para 72
⁶ See for example R v Glaxo Group Ltd's Patent [2004] EWHC 477 (Ch).
⁷ See Brugger v Medic-Aid Ltd [1996] RPC 63

The content of this article does not constitute legal advice and should not be relied on as such. Specific advice should be sought about your specific circumstances.

Herbert Smith LLP, Gleiss Lutz and Stibbe are three independent firms which have a formal alliance.

© Herbert Smith LLP 2008