The Oslo District Court declares Icos Corporation tadalafil patent invalid

On 11 July 2017 the Oslo District Court gave judgement in a patent dispute between Actelion Pharmaceuticals Ltd. v. Icos Corporation. The dispute concerned the validity of Icos Corporation`s Norwegian Patent NO 321 602 which pertains to tadalafil with a specified particle size. The specific particle size was obtained through so-called micronisation.

Tadalafil is the generic name of the active ingredient of the prescription drug Cialis for the treatment of erectile dysfunction (impotence) and Adcirca, for the treatment of pulmonary arterial hypertension (high blood pressure in the pulmonary vasculature). Tadalafil was a known compound at the priority date of the patent.

The issue before court was whether micronisation of tadalafil to obtain the specified particle size, fulfilled the patentability requirement of inventive step.

The Oslo District Court concluded that the patent was invalid because the person skilled in the art would have arrived at the method of micronising tadalafil and would have used this method to improve absorption and bioavailability. Hence, Icos Corporation`s Norwegian patent did not exhibit a sufficient inventive step.