24 August 2015

Court of Appeal overturns finding of invalidity on psoriasis ointment patents

On 28 July, the Court of Appeal gave its judgment upholding Leo’s appeal against Birss J’s finding that its EP (UK) patents nos. 1 178 808 and 2 455 083 relating to a combination ointment (Dovobet) for the treatment of psoriasis were invalid on the grounds of obviousness.  The Court of Appeal allowed the appeal, ruling that Birss J had made several errors of principle when finding that the invention was obvious. In particular, Birss J was wrong to conclude that there was a sufficient reasonable expectation of success for it to be ‘obvious to try’ the inventive step of the patent. Furthermore, the Court of Appeal felt that this was a classic case where there was a long-felt want for a number of years with no explanation as to why the invention had not been discovered earlier.


At trial, Birss J had accepted Teva’s argument that the Patents were invalid on the grounds of obviousness in the light of a prior art patent (Turi).  We discussed Birss J’s decision in our October 2014 Update and, in particular, the unusual nature of Teva’s obviousness argument: starting from the common general knowledge and adding in information from the prior art, rather than starting from the prior art reference. 

The key claims of the Patents are for an ointment consisting of two active ingredients (calcipotriol and betamethasone), a base (e.g. Vaseline) and a commercial available solvent (Arlamol E).  Both of the active ingredients were known in the art before the priority date as a sole active in a psoriasis ointment.  However, what was not known was a means in which to combine the two active ingredients into a single ointment due to conflicting chemical properties in aqueous solution.  Accordingly, the treatments could not be used together, either as part of a single ointment or as two separate ointments. However, as both active ingredients had significant and distinct benefits, many patients were prescribed both ointments and were advised to alternate between treatments, e.g. one in the morning and one at night. This more complex treatment strategy led to reduced patient compliance, in particular, in mild cases. There was therefore a desire amongst clinicians for an ointment in which both active ingredients could be effectively used in combination.

At first instance, Birss J decided that the Patents were invalid on the basis that the use of Arlamol E as a non-aqueous solvent to overcome the pH issues was obvious by the priority date.  Whilst it was not part of the common general knowledge, and was not one of the 10-20 solvents which a formulator would have tried, he said that the notional skilled formulator would not be “put off from including unfamiliar compounds merely because of their unfamiliarity”.  In light of Turi, he concluded there were sufficient grounds for the skilled formulator to include Arlamol E (which had the desired characteristics) in pre-formulation tests and the invention was therefore obvious to try. 

Court of Appeal decision

The Court of Appeal, in a decision given by Sir Robin Jacob, decided that Birss J had erred in principle and his decision should be overturned.  In particular, he had wrongly concluded that the idea of including Arlamol E as part of a research project amounted to obviousness.  As Sir Robin put it, the 'obvious to try' standard "requires a higher expectation of success than that", referring to his own decision in St Gobain where he had observed that "mere possible inclusion of something within a research programme on the basis you will find out more and something might not turn up is not enough. If it were ... the only research which would be worthwhile ... would be in areas totally devoid of prospect".   Accordingly, simply because Arlamol E had the desired characteristics, it did not follow that there were sufficient grounds to include it in pre-formulation tests.  There was nothing disclosed about it that made it an outstanding candidate over other solvents and whilst it might provide stability for the two active ingredients, there was no reasonably optimistic expectation that it would.

A further error of principle was the Judge’s failure to consider the fact that this was, as Sir Robin suggested, the “classic sort of case where the courts have found invention over the years, a long-felt want, the desired solution and no explanation of why that solution was not done before when it could have been".  A combination ointment had been desired by clinicians from at least the mid-1990s and represented a real advance.

Sir Robin also commented on the Judge’s apparent differentiation between “real formulators working in real organisations” and the notional skilled formulator – Birss J had said that, whilst familiarity with certain compounds would play a part in the choices made by real formulators, the notional skilled formulator would be less conservative in their approach.  Sir Robin described this as “rather odd” given that the law relating to inventive step requires the real prejudices and practices of persons skilled in the art to be attributed to the notional person.


In reaching his conclusion, Sir Robin noted, without surprise, that the EPO Opposition Division had also rejected Teva’s opposition on the grounds of obviousness, despite having been provided with a copy of Birss J’s judgment.

The Court of Appeal’s focus on the reasonable expectation of success test is particularly noteworthy. This is especially so, given the growing trend towards a more holistic approach to assess whether an invention is obvious.  It is rare for the Court of Appeal to overturn a finding of obviousness on appeal, given that the trial judge has been immersed in the arguments of the parties and their respective evidence. The Court of Appeal has, in overturning the decision, applied the reasonable expectation test in a manner which is more favourable to patentees.

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