In AGA Medical Corporation v Occlutech (UK) Limited, AGA Medical Corporation’s EP (UK) patent was found to be invalid by Mr Justice Roth.  Although the Opposition Division of the EPO also revoked the patent (now under appeal), the EPO and Mr Justice Roth reached different conclusions on several important points, highlighting the lack of harmonisation between the UK courts and the EPO. 

The patent at issue related to a device to be used to fill a hole in the heart. The device comprised of two discs joined by a cylindrical waist, where when inserted into the heart, the discs occupy a position on either side of the septum, to effectively plug the hole therein.  At least one of the discs was cupped to allow a better join with the septum.

AGA Medical Corporation claimed that Occlutech infringed the patent and Occlutech counterclaimed that the patent was invalid.

In particular, Occlutech indicated that the claims lacked novelty in view of the prior use of the device in a clinical trial.  Before the priority date of the application, a clinical trial had been carried out on three children in a hospital in Bratislava.  However, in order for the clinical trial to be relevant to the novelty of the patent, it needed to be established whether the device used in the clinical trial was one as claimed in the patent (particularly, whether at least one of discs of the device was cupped).  Further, it needed to be established whether the clinical trial was confidential.

The doctors who carried out the clinical trial gave inconsistent evidence and not all thought that the device had at least one cupped disc.  In spite of the evidence, Mr Justice Roth came to the conclusion that at least one of the devices used had a cupped disc. 

In contrast to this, the EPO Opposition Division was not convinced that a device with a cupped disc had been used in the clinical trial. 

With regard to confidentiality, Mr Justice Roth indicated that none of the doctors involved in the trial had been requested to sign a confidentiality agreement and that the doctors were not aware that the clinical trial was confidential.  Indeed, the doctors had briefed other doctors about the devices.  Mr Justice Roth therefore concluded that the clinical trial was not confidential and that the claimed device lacked novelty.

The Opposition Division of the EPO however arrived at the opposite conclusion and indicated that there is a prima facie assumption of confidentiality for clinical trials. 

With regard to inventive step, Occlutech argued that the patent was obvious over an earlier prototype which did not have cupped discs. Mr Justice Roth agreed with Occlutech in view of the opinion of one of the expert witnesses.  However, Mr Justice Roth disagreed with Occlutech’s insufficiency attack.

Occlutech also argued that the claims contained added matter.  Particularly, it was argued that the deletion of the feature of each end of the device being “contained by means for securing each end” added matter. Although Mr Justice Roth found that this did not add matter (because the application taught a method which could be used to produce a device of claim 1 where one end was not secured), the EPO Opposition Division found that the deletion of the feature did add matter.

Additionally, Occlutech indicated that the introduction of the feature of one or both discs being cupped added matter, as the feature was only essentially disclosed as part of specific embodiments.  Again, whilst Mr Justice Roth was of the opinion that this did not constitute added matter (in view of some discussion in the application that the cupped feature could ensure complete contact with the septum), the EPO reached the opposite conclusion and held that the cupped feature was tied to the discs being of different sizes.

Hence, although the EPO and Mr Justice Roth both came to the conclusion that the patent was invalid, this was on entirely different grounds.  The case highlights the different possible outcomes for a patent when assessed under different legal systems.