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UK Supreme Court clarifies test for obviousness for dosage patents

The UK Supreme Court has confirmed in a recent ruling (Actavis Group PTC EHF & Ors v ICOS Corporation & Anr [2019] UKSC 15 (27 March 2019)) that it remains the case that discoveries made through well-established or routine research protocols can be inventive.

The dosage patent, which was the subject of this appeal, EP(UK) 1,173,181 (“the 181 patent”), is owned by ICOS and exclusively licensed to Eli Lilly. The 181 patent relates to the use of a low level dosing (1mg to 5mg daily dose) regimen for tadalafil (the active ingredient in Lilly’s CIALIS medicine) for treating erectile dysfunction (ED). Actavis, Teva and Generics challenged the validity of the 181 patent. The key prior art patent (Daughan) disclosed that doses of tadalafil for the treatment of ED will generally be in the range of 0.5mg to 800mg for the average adult patient.

At first instance, Birss J found the 181 patent to be valid and infringed, notwithstanding that it was the result of a clinical programme with many routine and obvious steps from a starting point of a 50mg tablet. The Court of Appeal reversed the decision, finding the 181 patent to be invalid for lack of inventive step. In their opinion, it would have been obvious to the skilled team to arrive at the surprisingly low (but effective) dose using routine dose ranging studies. Lilly appealed the decision.

The case proceeded to the Supreme Court, where Lord Hodge took the opportunity to review the English court’s approach to the law of obviousness generally.

In addressing the statutory question of obviousness (whether the invention is obvious to a skilled person in the art, in view of any matter which forms part of the state of the art), it is common for English courts to adopt the so-called Windsurfing/Pozzoli approach. An alternative approach conventionally taken by the European Patent Office (EPO) is the so-called problem-and-solution approach.

Lilly argued that the Court of Appeal had not applied the law of obviousness correctly under the UK or EPO approach of finding invention where there was an unexpected technical effect (here, reduced side effects at a dose that worked). Lord Hodge was of the view that while both these approaches focus on the inventive concept of the relevant claim, neither should be approached in a mechanistic way. He confirmed that the question of obviousness must be considered on the facts of each case.

Lord Hodge considered that the Court of Appeal had been right to carry out its own evaluation, since Birss J had failed to appreciate the logical consequences of the finding that it was likely the skilled team would continue testing. Lord Hodge carried out his own analysis of the facts, setting out ten factors that were relevant to the context of the case, and concluded that the skilled team’s task in this case was to implement the key prior art patent (Daughan). Their target would be to determine the appropriate dose, which would usually be the lowest effective dose. And so, although the 5mg dose was effective and showed reduced side-effects, its identification was considered obvious.

The Supreme Court’s judgement confirmed the Court of Appeal’s finding that the 181 patent was obvious. Accordingly, it appears that a dosing regimen that would be reached by following standard clinical trial procedures to completion will not alone meet the statutory test for inventive step in the UK, however surprising the technical effect of the dosing regimen may be. Lord Hodge stressed that this did not mean that the product of well-established or routine research protocols cannot be inventive. He also reiterated that there is no policy reason why a novel and and inventive dosing regimen should not be rewarded by a patent. This judgement is likely to be the starting point in assessments of obviousness undertaken by the UK courts in the future.


If you have any questions on this topic, please contact Andy Cloughley at

Article written by Romi Korotana.

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