Germany: German Federal Court Decision: Influence of Clinical Phase I Studies on Inventive Step
In its decision of January 21, 2020, the German Federal Court (BGH) ruled on the question of inventive step in the context of a dose-effect relationship of (6R,12aR)-2,3,6,7,12,12a-hexahydro-2-methyl-6-(3,4-methylenedioxphenyl)-pyrazino[2',1':6,1]pyrido[3,4-b]indol-1,4-dione.
Behind this bulky IUPAC name is Tadalafil, better known under the trade name Cialis®. This is a PDE-5 inhibitor with a mode of action similar to Sildenafil, better known as Viagra®. The underlying patent in dispute claimed a unit dose composition of 1 to 5 mg. It was now to be clarified whether this specific dosage was based on an inventive step.
From the prior art a pharmaceutical composition comprising Tadalafil for the treatment of sexual dysfunction with an active substance content for a daily dose of 0.5 to 800 mg was known. This enormously wide range shows that these are the results of the phase I clinical study. However, the prior art does not disclose a maximum daily oral dose of Tadalafil.
Nevertheless, the BGH assumes that due to the positive results of the phase I study the skilled person would have carried out further phase II and III studies. In the phase II and phase III studies also the dose-effect relationship is regularly tested. This means that the skilled person would have been motivated to find out in further clinical trials in which range the beginning of the effect plateau for Tadalafil lies.
According to the BGH, "a technical teaching which produces an effect that is rather unlikely to be expected from a certain starting point is nevertheless obvious for the expert if it appears to be an obvious solution from a different perspective. In such constellations, the surprising effect must be regarded as a mere bonus effect" (see BGH decision, paragraph ).
The "UK Supreme Court" and the "Gerechtshof Den Haag" have come to a similar assessment as the BGH. However, the divergent position of some other courts in Europe (Finland, Denmark, Czech Republic) shows that this "surprising effect", i.e. the bonus effect, can have more weight in the decision on inventive step than the mere fact that studies on the dose-effect relationship could have been carried out.
BGH, Decision of January 21, 2020 - X ZR 65/18 (BPatG)