The UK Supreme Court rules on inventive step

April 2019

The UK Supreme Court has been unusually flush with patents cases of late. In 2017 the Court gave a ground-breaking ruling on the scope of protection of claims then, in 2018, it examined the role of plausibility in assessing insufficiency. To complete a trio of rulings on the big patent subjects in consecutive years, the Supreme Court has now given its decision on assessing inventive-step, and in particular the role of the obvious-to-try test, in Actavis Group PTC EHF & Ors v ICOS Corporation & Anor [2019] UKSC 15.

What is this decision about?

The inventive step requirement is found in Article 56 of the EPC (and is implemented in the UK in Section 3 Patents Act 1977):

"An invention shall be considered as involving an inventive step if, having regard to the state of the art, it is not obvious to a person skilled in the art."

The statutory question is therefore "is the invention obvious to a person skilled in the art?" When approaching this question, the UK courts use the well-established Windsurfing/Pozzoli test, but this does not answer the statutory question in itself.

In order to answer the statutory test a number of sub-tests have grown up. The most prevalent of these sub-tests is to ask whether the invention was 'obvious-to-try' in the expectation of some success. The level of expectation of success required was set by the House of Lords in Conor Medsystems Incorporated v Angiotech Pharmaceuticals Incorporated & Ors over a decade ago. Here it was held that 'obvious-to-try' is useful only in a case in which there is a "fair expectation of success".

Actavis v ICOS, however, illustrates that the obvious-to-try test must be kept in context as just one factor in the assessment of the statutory question and is not a substitute for it. In particular, although an expectation of success may indicate obviousness, the reverse is not necessarily true – an invention may be obvious for other reasons, even if its success was a surprise.

What happened in Actavis v ICOS?

Actavis sought the revocation of ICOS's patent relating to the use of tadalafil in a 1 to 5mg daily dosage form for 'sexual dysfunction', on a number of grounds including obviousness. The prior art disclosed use of tadalafil for erectile dysfunction in doses ranging from 0.5 to 800mg, daily. An example of the patent specifically concerned the use of a 50mg tablet of tadalafil.

The judge at first instance held that, starting with the prior art, the skilled team would not have a reasonable expectation that a dose as low as 5mg per day would provide a useful treatment for erectile dysfunction, nor any expectation at all that this would produce a clinically relevant effect with minimal side effects. He held, therefore, that the invention was not obvious.

The Court of Appeal, however, held that the first instance judge had lost sight of the fact that, on his own findings, the invention lay at the end of the familiar path through the routine pre-clinical and clinical trials process. In particular, wishing to apply the prior art, and after Phase I (proof of concept), Phase IIa ('go no-go') studies and then Phase IIb (dose-ranging) studies on doses of 25, 50 and 100mg of the drug to find a therapeutic plateau of at least 25 mg, it was nonetheless 'very likely' that the skilled team would investigate lower doses.

In the course of this, it was very likely that the skilled team would arrive at the claimed invention by testing a dose of 5mg tadalafil daily, finding it safe and efficacious. The 5mg dose would thus be arrived at by routine and therefore the fact that the skilled team would not have had a fair expectation of its success, or that they would be surprised by the efficacy of 5mg, was irrelevant. In other words, an expectation of success is not required if the invention is obvious for another reason, in this case carrying out routine testing.

The Supreme Court upheld the decision of the Court of Appeal that the patent is invalid for lack of inventive step. In doing so, the Court has emphasised that the assessment of inventive step is focussed on the statutory test, and this requires a multi-factorial assessment in every case. The Court sets out ten particular factors in this case that should be taken into consideration, only the first and eighth of which relate to the obvious-to-try with a fair expectation of success sub-test. In summary these are:

  • It is relevant to consider whether at the priority date something was "obvious to try", in other words whether it was obvious to undertake a specific piece of research which had a reasonable or fair prospect of success.
  • It follows that the routine nature of the research and any established practice of following such research through to a particular point may be relevant considerations.
  • The burden and cost of the research programme is relevant.
  • The necessity for and the nature of the value judgments which the skilled team would have in the course of a testing programme are relevant considerations.
  • The existence of alternative or multiple paths of research will often be an indicator that the invention contained in the claim or claims was not obvious.
  • The motive of the skilled person is a relevant consideration. The notional skilled person is not assumed to undertake technical trials for the sake of doing so but rather because he or she has some end in mind.
  • The fact that the results of research which the inventor actually carried out are unexpected or surprising is a relevant consideration as it may point to an inventive step.
  • The courts have repeatedly emphasised that one must not use hindsight, which includes knowledge of the invention, in addressing the statutory question of obviousness.
  • It is necessary to consider whether a feature of a claimed invention is an added benefit in a context in which the claimed innovation is obvious for another purpose.
  • The nature of the invention (in this case a dosage form patent).

On this basis, the Supreme Court held that a target of the skilled team, from the outset, would be to ascertain the appropriate dose, which would usually be the lowest effective dose. The pre-clinical and clinical tests involved familiar and routine procedures and normally progressed to the discovery of the dose-response relationship in Phase IIb.

In this case, the evidence clearly justified that the team would be very likely to test doses lower than the therapeutic plateau and so come upon the dosage regime which is the subject matter of the patent.

What is the impact of this decision on future cases?

Does the decision shift the balance between patentees and third parties? Holders of dosage form patents may be concerned that the Supreme Court held it to be a matter of routine in this case to explore dosages outside the therapeutic plateau even once the plateau had been established. Indeed, the IP Federation intervened in the case to express concern about a perceived risk that people might extrapolate from statements in the Court of Appeal's judgment that the result of routine investigations cannot lead to a valid patent claim.

Similarly, the UK Bioindustry Association expressed the concern that the decision could support the view that empirical research in the field of bioscience would not be seen as inventive when the methods of research are well-established. In response the Supreme Court, states that there is no such general proposition and each case must be assessed on its own facts and several factors:

"I do not interpret the Court of Appeal's judgments, …as supporting such an extrapolation. Kitchin LJ gave the leading judgment, in which he adopted a fact specific assessment based on the facts of this case and involving the weighing up of several factors, …I do not construe the judgments of the Court of Appeal as supporting any general proposition that the product of well-established or routine enquiries cannot be inventive. If that had been what the experienced judges had said, I would have respectfully disagreed. But it is not. …there is no policy reason why a novel and inventive dosage regime should not be rewarded by a patent."

The Supreme Court decision in Actavis v ICOS is largely a reminder that the essential question when assessing inventive step is: "is the invention obvious?" and that a multi-factorial approach will be taken to this, rather than mechanistic reliance on sub-tests or approaches.

This is actually a re-statement of what the English cases have always said rather than a new direction. Where the decision really assists is by providing a ready-made (but not necessarily exhaustive in every case) list of what the factors should include. This decision will therefore be the starting point when considering the inventive-step of patented subject matter in the future, particularly pharmaceuticals.

If you have any questions on this article or would like to propose a subject to be addressed by Synapse please contact us.


Paul England


Paul is a senior professional support lawyer in our London office specialising in patents law.

"...the essential question when assessing inventive step is: 'is the invention obvious?' and a multi-factorial approach will be taken to this, rather than reliance on sub-tests."