[2009] EWHC 1304 (Pat)

Mr Justice Kitchin handed down a decision only four weeks after the hearing, finding Cook’s patent invalid and not infringed by Edwards’ SAPIEN heart valve.

The technology involved an artificial heart valve made partially of pericardium (the tissue surrounding the heart) which is compressed onto a balloon catheter for percutaneous delivery via the femoral artery. Cook’s patent claimed a valve made of collagen containing biomaterial whereby the valve extended within the expandable stent substantially from the top of the stent to the bottom. Cook’s patent was amended before trial using the centralised EPO Limitation Proceedings to include the feature of ‘pericardium’ within claim 1, such that the claim read “wherein the valve is formed with a collagen containing biomaterial…[that] comprises pericardium”.

Despite third party observations to the requested limitation, the EPO indicated their intent to grant the limitation three months after Cook’s expedited request. The case was then tried based on the amended patent.

The Edwards heart valve, although made partially of pericardium (along with DACRON, a synthetic material), did not fall within claim 1 as the words “formed with” were found by Kitchin J. to limit the claim to a valve made only of pericardium. Kitchin J. found this interpretation consistent with the amendment to the specification which read “the valve material is a collagen containing biomaterial comprising pericardium”. Further, there was no infringement of the claim 1 feature “substantially”, as the valve of the Edwards device being only 75% the length of the stent was found not to be substantially from the top to the bottom of the stent. Edwards asserted a unique, and successful, argument disputing the priority of the Cook patent. The patent was said to lose priority as the PCT application was filed by Cook Biotech, whereas the US patent application, upon which the PCT based its priority, was filed by the inventors of the patent. The interests of the inventors were only assigned to Cook after the filing of the PCT application. The effect of Article 4 of the Paris Convention and section 5 of the Patents Act 1977 was such that Cook could not claim priority based on the US application as they had neither filed the US application themselves nor were they a successor in title to the inventors at the filing date of the PCT. In so finding Kitchin J. stated “[a]ny other interpretation would introduce uncertainty and the risk of unfairness to third parties.”