Kennametal Inc v Pramet Tools Sro & Anor

A stay of an order revoking a European patent should not ordinarily be granted merely because the patentee has begun central amendment proceedings in the European Patent Office. The court must consider whether UK validity proceedings remain live, whether an appeal is pending, whether the proposed amendments could and should have been advanced at trial, and the prejudice caused by delaying revocation. Where the UK proceedings have ended with a final unappealed judgment, and the amendments were not pursued during those proceedings, the uncertainty and delay associated with EPO proceedings will generally provide no sufficient justification for a stay.

The claimant sought a stay of an order revoking its European patent pending central amendment proceedings in the European Patent Office. The proposed amendments included combining claim 9 with claim 1 and introducing new method claims.

The claimant relied on Samsung v Apple [2014] EWCA Civ 250, in which the Court of Appeal had adjourned an appeal pending the outcome of a central amendment application. The defendants submitted that the present case was materially different because the UK revocation proceedings had reached a final judgment, no permission to appeal was sought, and the proposed amendments had not been raised at trial. The central issue was whether the pending EPO proceedings justified suspending revocation after the UK proceedings had finally ended.

1. The application was refused. The court declined to stay the order for revocation pending the EPO proceedings.
2. Samsung v Apple [2014] EWCA Civ 250 did not establish that a central amendment application justified a stay whenever such an application was made. The Court of Appeal had reserved the question whether pursuing central limitation while litigating UK validity and infringement issues could be abusive. Its decision operated in the context of concurrent UK and EPO proceedings and a pending appeal.
3. The present case was materially different. The UK revocation proceedings had ended in a final judgment that the patent was invalid, and the claimant did not seek permission to appeal. The circumstances which had supported suspension in Samsung v Apple, including the continued subsistence of the patent while a suspension remained in place, were therefore absent.
4. The court also took account of the fact that the proposed amendments had not been advanced during the UK proceedings. Claim 9 had not been asserted to be independently valid, despite evidence addressing its invalidity. The proposed method claims could likewise have been advanced at trial. The court considered that the Henderson v Henderson doctrine made it abusive to seek, after final judgment, to assert matters which should have been raised earlier.
5. Delay and prejudice also weighed against a stay. The EPO proceedings had an uncertain duration and might involve an appeal. The defendants could face uncertainty concerning future products or modifications if the patent were later validated by amendment. Weighing those factors, the court held that it was not justified to await the uncertain outcome of the EPO proceedings before revoking the patent.

First-instance decision. The judgment records no application for permission to appeal.