Patents

Case Note Boston Scientific Limited and Another v Julio C Palmaz and Others (first Instance)

Jane Lambert

Oct 1998
Last updated 15 Nov 2005

This article formerly appeared on the Lancaster Buildings website

This litigation concerned an invention for a coronary stent used in percutaneous coronary angioplasty. This procedure removes blockages from coronary arteries by inserting a catheter with a sausage shaped balloon tip through a patient’s skin into the coronary artery, guiding the tip to the affected area and inflating the balloon inflates to a very high pressure. Stents are used to support the artery after the blockage has been removed. Various types of stents have been used over the years but their shape and size after insertion could not be controlled. There was always the risk that a stent that was too small would be dislodged while one that was too large could rupture the artery.

The Patents

The first defendant, Julio Palmaz ("Dr. Palmaz") addressed this problem by fitting a wire-mesh construction over the balloon. It expanded with the inflation of the balloon so that it was always the right shape and size and remained in place after the arterial blockage had been cleared. Boston Scientific Ltd. and Advanced Surgical Intervention Inc. ("Boston") also manufactured an expandable stent but theirs was designed to be crimped over the balloon. Dr. Palmaz applied to the European Patent Office ("the EPO") for two European patents, called respectively Palmaz I and Palmaz II, on 7 Nov 1986 and the 28 Mar 1988.

Palmaz I

The application for Palmaz I was granted on the 30 Jan 1991. Immediately afterwards, Boston opposed the grant. As a result of its opposition Palmaz I was revoked on the 16 Jun 1993. Dr. Palmaz appealed to the Technical Board of Appeal, which set aside the revocation. The patent was re-granted in an amended form on the 6 May 1998. Thereupon Boston and Advanced appealed against the re-grant. Before that appeal could be determined in the EPO, Boston applied to the Patents Court for a declaration of non-infringement and revocation of Dr. Palmaz’s patents. Dr. Palmaz counterclaimed for infringement of his patent. As the effect of Dr. Palmaz’s appeal was to suspend the revocation of his patent and the effect of Boston’s appeal against the re-grant was to suspend the re-grant, Dr. Palmaz applied to the Patents Court to amend Palmaz I. Pumfrey J refused Dr. Palmaz leave to amend his patent on the ground that the amendments would introduce additional matter that had not previously been disclosed contrary to art 123 of the European Patent Convention. Applying the tests in Catnic v Hill & Smith [1982] RPC 183 and Improver v Remington [1990] FSR 181 his lordship held that the Boston stent did not infringe the patent. Finally, he found that Palmaz I was invalid in that certain features of the invention had been anticipated in an earlier American patent, Dr. Palmaz himself had disclosed other features in various discussions in a bid to raise funds and such features as had not been disclosed would have been obvious

Palmaz II

This patent was for the connecting features of a tubular stent functioning in much the same way as Palmaz I. Boston also made a tubular stent but its connectors were different. As to whether Boston’s stent infringed Palmaz II, Pumfrey J applied the Improver test. In his lordship’s judgment, the Boston stent fell outside the claim because the variant did have a material effect on the way the invention worked. The learned judge also found that the invention was obvious in view of Palmaz I.

Appeal

Dr Palmaz appealed unsuccessfully against Pumfrey J's to the Court of Appeal (see appeal case note).

 

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