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Your European Patent is Being Opposed – How to Prepare for an Opposition

The grant of a European patent by the European Patent Office (EPO) is a major step in the protection of an invention. However, it is not the final step! A granted European patent may be opposed if a third party launches opposition proceedings within a nine month period starting from the grant date of the patent.

We’ve prepared a handy checklist in the event your European Patent is being opposed. Our Opposition and Appeals team is available to guide you, please don’t hesitate to get in touch.

What should you check?

Assess the strength of the opponent’s case

Issues to consider: The relevance of the prior art cited by the opponent and other prior art known to you (check publication dates of any cited material).

Evaluate amendments to limit the scope of claims

Issues to consider: What reduced scope of claims would be acceptable? What basis is there in the application as originally filed for useful amendments?

Amendments to the claims filed late may not be accepted. It is therefore very important as proprietor to consider auxiliary requests as fall-back positions. The number of auxiliary requests should however remain relatively limited and a convergent approach should be adopted.

Although clarity is not a ground for opposition per se, the patent must satisfy all the articles and rules of the European Patent Convention after the claims have been amended.  Any amended claim should also be reviewed to determine if it has an acceptable scope.

Undertake searches/experimentation

Issues to consider: Evidence and arguments cannot usually be introduced at a later stage.  This is the last opportunity to conduct comparative testing or undertake the preparation of other evidence. Collecting or producing new data may be a lengthy process. It is therefore essential to evaluate the need for such data promptly.

Research history of invention and/or alleged prior use

Issues to consider: If the opponent has cited prior use or prior public disclosure of the invention as prior art, check the actual circumstances. Was the disclosure really public? Did it actually occur under terms of confidentiality?

Identify expert witness

Issues to consider: Are witnesses required to counteract a witness proposed by the opponent? Are any witnesses required to counter claims of prior use or prior public disclosure? Note: The EPO is generally reluctant to place too much weight on witness statements relating to what the “person skilled in the art” would do or think. However it will usually take at face value any witness statements about “prior use”, unless these are challenged by other evidence and/or witness statements.

We are here to help – contact Michael or Laura for further information:

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