EP Patent Opposition and Appeal

Granted European patents can be opposed by third parties at the European Patent Office (EPO). EPO opposition and appeals are a specialist area of practice. Successfully defending or opposing a patent requires not only a detailed understanding of law and case law but also experience in strategy. Our team at CMS is routinely sought out for their advice and representation in both defensive and offensive EPO post-grant oppositions. We also have a wealth of experience at the appeal level representing clients who have been adversely affected by an EPO decision, with a view to achieving a more commercially desirable decision. 

EPO Opposition Divisions and Boards of Appeal experience

We have significant experience in oral advocacy at hearings before the EPO Opposition Divisions and Boards of Appeal. A number of our attorneys have been involved in defending and attacking commercially important patents in multi-party proceedings. Often, these proceedings have involved multiple inter-related patents and have run alongside national litigation proceedings. 

Even where we have not been responsible for prosecution, cases are often transferred to CMS for our expertise in representation during post-grant proceedings. For those patents of particular commercial value and where an opposition is expected, transferring responsibility soon after grant enables our attorneys to provide early ‘pressure-test’ advice as to how a patent might stand up in EPO opposition and appeal proceedings. Given the EPO’s streamlined approach to opposition proceedings, where a response to an opposition might be required within only 4 months, patentees can benefit from the additional time that this advice can provide to strengthen their position, for example by conducting a more extensive evidence search and/or additional experiments and, if appropriate, enlisting technical expert assistance.  

Our team also has experience in representing clients at the UKIPO. 

Examples of our recent experience include:

• Representing Kymab Limited in oppositions against several Regeneron patents relating to a platform for antibody discovery (both before the Opposition Division and Appeal Boards), with the proceedings running alongside national litigation. We also represent Kymab in defending patents for their antibody discovery platform and in opposition proceedings relating to CRISPR Cas9 technology.
• Acting on behalf of Eli Lilly and Company in EPO opposition and appeal proceedings relevant to clearing the way for their migraine biologic.
• Representing Vectura Group in defending patents relating to inhaled therapeutics, with national litigation running in parallel.
• Acting for Insmed Incorporated in EPO oppositions relevant to the protection of their phase III asset ALIS.
• Representing Silence Therapeutics in opposition proceedings in the field of siRNA therapeutics, with national litigation again running in parallel.
• Acting on behalf of a medical device manufacturer in oppositions at the EPO.
• Representing a telecoms company in a series of oppositions relating to cellular roaming.
• Representing Microsoft before the EPO Board of Appeal to appeal Examining Division decisions.

More information about EPO Opposition procedure and the EPO Rules of Procedure of the Boards of Appeal can be downloaded below.

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