The English Patents Court was the third court in Europe to adjudicate on infringement Occlutech GmbH v AGA Medical Corp and Another [2009] EWHC 2013 (Ch).

Having reached diametrically opposed views on the construction of claim 1 of AGA’s patent, the German court held Occlutech to infringe whilst the Dutch court found no infringement. The English judge agreed with the latter.

The patent claimed medical devices made of braided metal (typically Nitinol), whereby the devices when implanted have a generally dumbbell shape “…characterised in that clamps (15) are adapted to clamp the strands at the opposed ends of the device.” The judge held the Occlutech devices did not infringe based on the construction of the word “clamps” and the phrase “opposed ends of the device.” He was not convinced that the patentee had made a “dictionary definition” in the specification for the word clamp. Although the specification referred to alternative methods of securing the ends, they were specified as alternatives only. It was not apparent to him why the patentee should intend to exclude such alternatives. However, the drafting of claim 1 was “so clear that the actual wording cannot be ignored…and the relevant words cannot be extended beyond their natural wording…” Instead of a clamp, the Occlutech devices were welded. Although welding was listed as an alternative to clamping in the specification, the word “clamp” within the claim did not extend to welding. Further, the Occlutech devices did not infringe as they were welded at only one end. Although not welded at “opposed ends of the device” the argument presented by AGA was that the Occlutech devices achieved the same functionality as the claimed invention. The judge was not convinced: “[t]o adopt this approach is not successfully to adopt a purposive construction of the patent; it is to go way beyond what seems clearly to be a specific limitation, deliberately included, even though one cannot glean why that limitation might be there.” Accordingly, the Occultech devices do not infringe the UK patent.

The Düsseldorf Higher Regional Court construed claim 1 of the corresponding German designation of the patent wholly differently. Welding was included within claim 1 and a ring positioned over the welding of the Occlutech devices fulfilled the same purpose as a clamp. Although the court agreed that claim 1 described clamping at either end “the average skilled person will not content himself with this mere linguistic understanding.” The technically meaningful understanding of the claim would not limit the skilled reader to two clamps or welds. Accordingly, the Occlutech devices infringe the German AGA patent.

The UK AGA patent was found valid by the English judge. The only prior art document was a Boston Scientific patent disclosing a knitted stent. Each of the braided metal, dumbbell shape, and clamping of claim 1 were not obvious and moreover when in combination there was a clear inventive step.