Boston Scientific Ltd & Anor v Palmaz & Anor

On an appeal by way of rehearing, a European patent must be considered in the form resulting from a final amendment by the European Patent Office where that amendment has retrospective effect under the Patents Act 1977.

Patent claims are construed according to their words and technical context. A court should not enlarge a claim to cover a substantially different device, particularly where the alleged variant omits several specified features. The construction must provide reasonable protection for the patentee and reasonable certainty for third parties.

Obviousness is assessed using the structured Windsurfing approach. The skilled person is assumed to consider pleaded prior art with interest. Commercial attractiveness and hindsight are not the tests. An appellate court should be cautious before differing from a trial judge on an evaluation involving matters of degree.

Boston Scientific brought declarations of non-infringement and petitions to revoke two European patents concerning expandable intraluminal grafts or stents. Pumfrey J held both patents invalid and not infringed and ordered their revocation, subject to a stay pending appeal.

Before the appeal, the European Patent Office had allowed amendments to Palmaz 1. The appeal therefore required the Court of Appeal to determine the effect of those amendments, and to reconsider infringement and validity on the amended patent. The principal issues were whether the NIR stent fell within the claims, whether Palmaz 1 lacked novelty or was obvious, and whether the connector arrangement claimed in Palmaz 2 was obvious.

1. Disposition. The appeal was dismissed. Both European patents were revoked. The appellants were ordered to pay 95 per cent of the respondents’ costs of the appeal.
2. Effect of EPO amendment. Per Lord Justice Aldous, the appeal was by way of rehearing. Because the EPO amendments had become final while revocation was stayed, sections 77(4), 27(3) and 75(3) of the Patents Act 1977 required the amendments to be treated as having effect from grant. The Court therefore had to consider the amended form, which was the only form of the patent existing at the hearing.
3. Palmaz 1 infringement. Features B, H and I required intersecting first and second elongate members, with some second bars cutting into first bars, and each pair of first bars joined by at least two second bars. Those features could not be identified in the NIR stent. The claim had been amended to add characterising features supported by the illustrated construction. It could not properly be widened to cover a wholly different design. The construction had to preserve reasonable protection and reasonable certainty for third parties, consistently with the Protocol on the Interpretation of Article 69 of the European Patent Convention and section 125 of the Act.
4. Palmaz 1 validity. The trial judge’s findings that the slotted-tube embodiment had been disclosed at the Shiley meeting and at the RSNA presentation were supported by the evidence and were upheld. The patent therefore lacked novelty. Alternatively, applying the structured approach in Windsurfing International Inc v Tabor Marine (Great Britain) Ltd, the slotted-tube construction was obvious from the Annex III drawings and common general knowledge. The court rejected an approach requiring the skilled person first to recognise commercial worth or a need for improvement.
5. Ersek and added matter. The claim was also obvious over Ersek, because the provision of circumferential members by using slots rather than slits was an obvious workshop modification. The added-matter issue under sections 72(1)(d) and 76(2) was left undecided because the patent was invalid on other grounds.
6. Palmaz 2. The NIR was a single flexible tubular member, not a plurality of tubular members joined by connector members. It therefore did not infringe. Flexible connectors between tandem stents were obvious, and claims 2 and 3 were also invalid for obviousness.

• Court of Appeal (Civil Division): [2000] EWCA Civ 83 — appeal dismissed; European patents revoked.
• Chancery Division: Pumfrey J held the patents invalid and not infringed and ordered revocation, subject to a stay pending appeal.