News Item
Split decisions in UK and Germany on claim construction
25 June 2010
Parallel European Patent litigations between Occlutech and AGA Medical Corporation in the UK and Germany illustrate that the two countries can look at claim construction differently, despite the European Patent Convention (EPC) encouraging a uniform approach.
The standard for construing patent claims is EPC Article 69 and its Protocol. The results need not always turn out the same - courts can apply the same approach but come to different conclusions. But in this case, between the same parties on the same facts, which reached the same level in the UK and in Germany, the courts reached different results based on different approaches. The case in the UK is Occlutech v AGA Medical [2010] EWCA Civ 702 decided in the Court of Appeal on 22 June 2010.
The patent is for a collapsible medical device such as a heart occluder. The device is made from metal strands braided into a fabric. In its expanded state it is dumbbell or yo-yo shaped. It is collapsible for delivery to the site through a catheter. On arrival at the site, it springs back to its original shape. Claim 1 of the patent in suit (EP 808138) requires the device to be “…characterized in that clamps are adapted to clamp the strands at the opposed ends of the device.” An embodiment shows a device formed from an open-ended tubular braid with clamps at both ends in order to prevent the braid from unravelling.
The accused device was made from a “sock” of braided material, having loose strands at one end only. The loose strands at the open end were then held together by welding. There was nothing of that sort at the other end.
The UK Court of Appeal held that the words in the claim, requiring clamps (plural) at opposed ends (plural) were distinctive and necessary features of the claimed invention. The claims do not refer to a “one-ended” device; they refer only to a device with clamps “at opposed ends”. The Occlutech device did not infringe. (As a separate point, the court also held that a weld was not in any case a “clamp” within the meaning of the claim).
The Düsseldorf appeal court (Oberlandesgrericht - OLG) came to an opposite conclusion on the “two clamps” point. This was based on a passage in the specification which referred to a flat sheet of metal fabric being used to form a pocket instead of a tube. The patentee’s case was that a device formed from a flat sheet would have free strands at one end only, and would need clamping only at that end. And because the patent did disclose a flat sheet as a starting material then the claim should be interpreted so as to encompass a “one-ended” device. The court held that Occlutech’s device infringed. (The German courts also held that the Occlutech device did have a clamp in the first place).
To say that a claim requiring two clamps can cover a device with one clamp involves departing from the conventional meaning of words. In the UK, the circumstances in which a patentee is assumed to have done that are rare. An extended meaning can only be justified where, for example, the language of the patent as a whole compels that conclusion. Comparing the two decisions shows these differences in approach:
• The German courts in this case proceeded on the assumption that a patent claims as much as it teaches, and worked back from that. The UK approach is that this would not cater for the possibility that the patentee has, for reasons of his own, deliberately limited the scope of the claims – for example, because of prior art, or to avoid arguments with the examiner about enablement. As was said in Kirin-Amgen in the UK: “There is no presumption about the width of the claims. A patent may, for one reason or another, claim less than it teaches or enables.”
• The Düsseldorf OLG used a method claim as an aid to construing the main product claim. That method claim was however dependent on the main product claim. The UK Court of Appeal did not consider that the skilled addressee reading the method claim would apply a wider meaning to the unambiguous language of the main product claim.
• The UK Court of Appeal took account of the fact that the patentee had a divisional application, which is referred to on the face of the patent in suit. The skilled addressee would at least consider the possibility that the “flat sheet” method, unsupported by the language of the claims, was being hived off to a separate patent (which is in fact the case; the divisional patent is now granted). That possibility was not raised in Germany.
The UK Court of Appeal commented in its judgment on the Düsseldorf OLG’s decision, which had been handed down at an earlier date. There is a pending application to the German Supreme Court for leave to have the decision reviewed. It remains to be seen whether the decision is a correct application of German law, or whether there should be a recognition of what the patentee intended to claim, as viewed through the eyes of the skilled addressee. A parallel action in the Netherlands resulted in the same outcome as in the UK (the outcome of an appeal by the patentee is awaited).
Marks & Clerk Solicitors LLP represented the successful party Occlutech GmbH in the UK Court of Appeal.
For more information about this case, contact your usual Marks & Clerk solictor, or Gregor Grant at ggrant@marks-clerk.com.