Cook Biotech Incorporated v Edwards Lifesciences AG

In assessing patent obviousness, the court must identify the skilled person and common general knowledge, the inventive concept, the differences from the prior art, and whether those differences required invention, while avoiding hindsight. Where a patent is addressed to a multidisciplinary team, the team’s pooled knowledge and experience govern construction and obviousness. A stent is not artificially divided by assigning different functions to structurally integral parts where the device is designed and described as a single stent. Known measures to support and reinforce valve leaflets may make a specified restriction in the valve opening obvious. An arbitrary numerical minimum adds nothing inventive where it merely reflects the obvious need to strengthen the valve and prevent tearing.

Cook, the proprietor of a patent for a catheter-deliverable stent valve, appealed against an order of Mr Justice Kitchin dated 12 June 2009. Edwards had sought revocation and Cook had counterclaimed for infringement. The Judge revoked the Patent for obviousness over Andersen and held that it was not infringed.

Cook challenged the construction of the Patent, the obviousness findings concerning claim 1 and claims 15 and 22, the infringement decision and the priority-date analysis. The parties agreed that the court should first determine obviousness over Andersen. If that challenge failed, the remaining issues would fall away. The central issue was whether Andersen made the claimed stent valve and the subsidiary numerical limitation obvious.

1. Disposition. The appeal was dismissed unanimously. The Court held that the Judge’s findings of fact concerning claims 15 and 22 could not be impugned and that his conclusion on obviousness was correct. It was therefore unnecessary to hear argument on the remaining grounds concerning priority, construction matters not material to obviousness and infringement.
2. Applicable approach. The Court accepted the four-stage obviousness inquiry explained and reformulated in Pozzoli Spa v BDMO SA [2007] EWCA Civ 588: identify the skilled person and common general knowledge; identify the inventive concept or construe the claim; identify the differences from the prior art; and ask, without hindsight, whether those differences were obvious or required invention. The Court also agreed that simplicity is no bar to invention and that a simple solution can appear obvious after it has been explained, as stated in Haberman v Jackel [1999] FSR 683 at 697.
3. Claim 1. The Patent and Andersen were addressed to a team including an interventional cardiologist, a cardiac surgeon, a bioengineer and a person familiar with implantable surgical heart valves. Their pooled knowledge governed the interpretation of stent. The Andersen structure was designed and described as a single stent. Its taller commissural loops formed an integral part of the upper ring, supported the valve, could contact the lumen and moved radially outwards with the rest of the structure. It was artificial to divide those parts according to function. Andersen therefore disclosed the relevant stent arrangement, and replacing its porcine valve with a fabricated pericardium valve and using a single stent with valve leaflets extending substantially between its ends was obvious.
4. Claims 15 and 22. The evidence entitled the Judge to find that known measures for reinforcing leaflet edges and keeping them away from the stent wall might result in a restriction of 1mm from the stent perimeter. Even if that conclusion were not accepted, the 1mm figure had no inventive significance. It merely reflected the obvious need to secure and strengthen the leaflet edges and prevent tearing.

• Court of Appeal (Civil Division): Cook’s appeal was dismissed after the Court upheld the conclusion that the Patent was obvious over Andersen.
• Chancery Division: On 12 June 2009, Mr Justice Kitchin revoked the Patent for obviousness and held that it was not infringed.