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Opposing a European Patent? Read our handy checklist

Looking to oppose a European patent? Here is a handy checklist of points to consider.

The ongoing monitoring of the activities of competitors at the European Patent Office is very important to be able to take early action. A well planned patent monitoring programme is a cost-effective way of enabling you to review the prosecution of your competitor’s European Patent applications, take the appropriate action at an early stage, and build your case well within the set limits.

If you are opposing a European patent and you have to file a Notice of Opposition, check the following:

Assess why an opposition should be filed

Issues to consider: Is the patent being attacked globally? What will be the effect on commercial relationships? Is it better to approach the patent proprietor and seek a confidential commercial solution, e.g. a royalty free licence? Should the opposition be filed anonymously?

Assess what is expected of the opposition

Issues to consider: Is revocation of the entire patent sought?  Or just the limitation or removal of certain claims?  What reduced scope of the claims would be acceptable?

Undertake searches

Issues to consider: Evidence and arguments cannot be introduced at a later stage. This is the last opportunity to complete prior art searches.

Research history of invention

Issues to consider: Investigate whether there was prior use or prior public disclosure of the invention.  Carry out inspection of prosecution files of corresponding patent applications in all relevant territories.

Identify expert witnesses

Issues to consider: Which witnesses are required? Are any witnesses required to testify to a prior use or prior public disclosure? Is any experimentation required, and if so, who should do it?

For further information about the opposition process, please contact our Murgitroyd EPO Opposition and Appeal Team.


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