European Patent Opposition Procedure

Nine months after grant to oppose a patent

During the nine-month period following grant of a European patent any third party may give notice of opposition to the patent to the European Patent Office (EPO). An opposition may be filed only on the grounds that:

i. the invention as claimed lacks novelty;

ii. the invention as claimed lacks inventive character;

iii. the invention is not disclosed in a manner sufficiently clearly and complete for it to be carried out by a person skilled in the art;

iv. the invention is otherwise unpatentable (i.e. is not regarded as an invention; is excluded from being patentable; or is not industrially applicable); and

v. the subject matter of the European patent extends beyond the content of the application as filed.

Written submissions

Notice needs to be given in written form and must contain the grounds on which the opposition is based, as well as an indication of the facts and evidence supporting these grounds. The opposition fee must be paid (rate as of April 2024 €880).

If the opposition is found to be admissible, the EPO communicates the notice (or notices, if more than a single party has filed an opposition) to the proprietor shortly after the nine-month period. The proprietor will then be given the opportunity to file observations to the notice, within a period of time determined by the Opposition Division, typically four months. Observations may include, in addition to argumentation, amendments to the claims, or indeed any part of the patent specification.

Although the European Patent Convention (EPC) permits the Opposition Division to communicate with the parties “as often as necessary”, in practice once the Opposition Division has received and studied the notice(s) of opposition and the response of the proprietor, the next procedural step is often the issuance to all parties (i.e. opponent and proprietor) of a summons to oral proceedings. At least two months’ notice must be given to the parties ahead of oral proceedings. However, in all likelihood, practicalities will dictate that parties are given more notice. The summons will contain a deadline, fixing a date by which any further written submission shall be filed. When making submissions which include amendments to the specification, it is common practice for the proprietor to file a series of reasoned requests. A main request will be addressed first, and, if the proceedings cannot be concluded at the main request, the remaining auxiliary requests will then be considered in order as appropriate. The summons will prepare everybody participating in the oral proceedings by drawing attention to the points that need to be discussed. It is likely that the text of the summons will extend to a fairly full analysis of the submissions (main and auxiliary) by the Opposition Division.

Attempts to submit further evidence or facts ahead of the deadline in the summons will be considered by the Opposition Division within the contexts of fairness of the procedure to all parties and of procedural efficiency. It follows that this deadline should not be seen as a general invitation to file additional submissions. As is often the case, it is to the advantage of any party to present their case as fully and as early as possible in the procedure.

Oral proceedings

On the day of oral proceedings (which are open to the public), the Opposition Division will hear oral arguments from all parties, and it is likely that the Opposition Division will, following deliberation, announce its decision orally at the end of the hearing. The decision will then follow in written form with reasoning, perhaps a month after the hearing.

The EPO currently endeavours to complete straightforward opposition cases within 18 months of the end of the opposition period, with a view to reducing uncertainty for parties affected by the outcome. Expediency is important, as cases sitting with courts, including the Unitary Patent Court (UPC), will often be stayed until a decision from an EPO opposition procedure is delivered.

Appealing the Decision

Whatever the decision (i.e. revocation of the patent; rejection of the opposition; or maintenance of the opposed patent in amended form), it will be open to appeal. Any notice of appeal must be filed within two months of written notification of the decision, and a statement setting out the grounds within four months. The establishment of the UPC has increased the importance of expediency of procedure. In recognition of this, requests for accelerated processing of appeal proceedings before the EPO Boards of Appeal (BoA) are accepted according to the published Rules of Procedure of the BoA by parties to the proceedings (with justification) and by any national court, other competent authority in an EPC contracting state, or the UPC (without justification).

It is also possible to challenge the validity of a European patent, in respect of the countries which are members of the Unitary Patent, through the Unified Patent Court, unless the proprietor has filed an opt out.

Our attorneys have extensive experience of opposition proceedings, both as the party filing the opposition and in defence of an opposition filed by a third party. If you have any questions about filing or defending an opposition, or would like a cost estimate to do so, please contact one of our European patent attorneys or complete our contact form.