In the case of AGA Medical Corporation vs. Occlutech (UK) Limited, the British High Court of Justice declared AGA's patent to be null and void. Although the European Patent Office's (EPO) Opposition Division has also revoked the patent, they made their decision on entirely different grounds. This difference of opinion emphasizes yet again the lack of harmonisation between the national courts and the EPO.
The AGA patent relates to a medical device to be used to fill a hole in the heart. This is a necessary medical procedure for a particular heart defect. The device described in the patent claims comprises two joined discs which, when inserted into the opening in the heart, form a surface on either side of the opening, to effectively plug the hole. At least one of the discs is cupped, to create a tighter seal.
Confidential or not
Occlutech alleged that the patent claims were familiar from non-confidential prior use of the device described in the claims, during a clinical test that had taken place before the priority date. The British High Court of Justice took the view, based on the clinical trial conducted by doctors, that the devices used were indeed the same as the devices described in the patent claims. The EPO, in contrast, was not convinced of this and reached the opposite conclusion, namely that the devices were not the same as the devices described in the claims. Furthermore, the Dutch District Court and the EPO deemed the clinical trial to be confidential. This contradicts the view taken by the British High Court of Justice.
Occlutech further argued that the patent claims contained added matter. In particular, it was argued that the deletion of a feature of the device and the addition of the feature that at least one of the discs had to be cupped constituted added matter. Both the British and the Dutch High Court took the view that these changes did not constitute added matter. The EPO again took the opposite view, concluding that the patent claims did contain added matter.