Pages 408-411

INFORMATION FROM THE CONTRACTING / EXTENSION STATES

GB United Kingdom

Decision of the Court of Appeal of 20 March 2000¹

Headword: "Palmaz European Patents (U.K.)"

Patents Act 1977 ss 2(2), 3, 27(3), 75(3), 77(4), 125(1)

Keyword: Action for declaration of non-infringement and petition for revocation - Amendment in the EPO - construction of amended claim

Summary

In actions for declarations of non-infringement and petitions for revocation, the two patents in suit EP 221 570 (referred to as "Palmaz 1") and EP 335 341 (referred to as "Palmaz 2"), related to expandable devices called "stents" for supporting the walls of a body passageway to keep a lumen or tube open and having an important use in the treatment of coronary artery disease. The alleged infringement was a stent of a different design referred to as the "NIR" stent".

Palmaz 1 had been successfully opposed in the European Patent Office and then on appeal held to be allowable with amended claims. The final form of the specification, however, was still not known on 26 June 1998 when the trial judge gave judgment in the Patents Court.2 He concluded that the text of the patent before him must be the unamended form, including the unamended claims which had been accepted to be invalid, and that amendment should not be allowed; it followed that the patent should be revoked. However, he also considered the amended claims that had been allowed in the European Patent Office, and he concluded that even with such amended claims the patent was invalid and also that the NIR stent would not have been an infringement.

The specification of Palmaz 1 described the invention with reference to two pairs of figures, each showing a stent before and after expansion. Figures 1A and 1B showed what was (by the amendment) acknowledged to be prior art: a wire mesh tube made of continuous stainless steel wire woven in a criss-cross tubular pattern. Figures 2A and 2B showed as an embodiment of the invention a tube consisting of intersecting first and second bars all of uniform rectangular cross section, each second bar circumferentially extending only between a pair of first bars and these being interconnected by at least two second bars. The structure could be produced by etching a stainless steel tube to form the slots between the bars. Such structural features had been added to claim 1 by the amendment.

The respondents denied that these features were present in the NIR stent.

In two oral presentations before the priority date of the patent, the inventor had displayed drawings similar to those of figures 1A and 1B and alongside them drawings similar to figures 2A and 2B. He said that only the former drawings and the wire mesh construction had been discussed and not the latter drawings and the slotted tube construction, but the judge found that on the balance of probabilities anticipation had occurred. He found that if there had been no anticipation the invention was obvious in view of the drawings alone.

The judge also found that the amended claims were obvious in view of a US patent ("Ersak")published eight years before the priority date.

The invention of Palmaz 2 related to devices of the type disclosed in Palmaz 1 (which was a prior publication) joined together by flexible connecting members. The respondents submitted that the NIR stent was a single flexible tubular member, not a plurality joined by a connector, and did not fall within the wording of the claims. The judge found that Palmaz 2 was invalid and not infringed.

The patentees appealed to the Court of Appeal.

Meanwhile, on 20 October 1999, Palmaz 1 was finally amended in the European Patent Office. In the Court of Appeal the respondents argued that the patent could only be revived in the United Kingdom by first reversing the judge's conclusion on amendment, for which the court must be satisfied that the amendments were allowable.

Held, dismissing the appeal and revoking the patents:

1. When a European patent had been amended by a final decision in the European Patent Office, the amendment had effect retrospectively from the grant of the patent and the amended patent was the only form that existed.

2.The judge had been correct to conclude at a time when the form of the claims of a European patent was known but the final form of the specification was not that the text of the European patent (UK) from which the proprietor derived his rights was still the unamended form including the unamended claims.

3. Claim 1 of Palmaz 1, which was solely supported by figures 2A and 2B and their associated description, could be expected to contain those features which were designed to differentiate the invention from the prior art. It would therefore be surprising if the claim covered the NIR stent which was a completely different design. The judge had correctly decided that it did not.

4. There was ample evidence on the first occasion of alleged anticipation and sufficient on the other for the trial judge's findings of fact, and the court should not interfere with them.

5. It was not an answer to an attack of obviousness that the skilled man would not have realised that the drawing in question was worth pursuing and that he would not have been looking for a deficiency in the known device which needed to be improved. It was necessary to assume that the skilled man considered the pleaded prior art with interest. There was but one question to be asked: was the invention as claimed obvious having regard to matter that formed part of the state of the art, not whether it would have appeared commercially worthwhile. The best way to arrive at the right conclusion was the structured Windsurfing approach adopted by the judge.

Windsurfing International Inc. v. Tabur Marine (Great Britain) Ltd [1985] R.P.C. 59 at 73, CA per Oliver L.J., and Brugger v. Medic-Aid Ltd [1996] R.P.C. 635 at 661, Laddie J., followed.

6. Although there was force in the patentee's submission that the skilled man would not have believed it obvious to modify the method of making Ersek by using slots, the judge had approached the issue correctly and there was a sound basis for his conclusion which should be upheld.

Biogen Inc. v. Medeva PLC [1997] R.P.C. 1 at 45, HL, per Lord Hoffmann, applied.

GB 1/01