Opposition Proceedings Before The European Patent Office

The opposition procedure before the European Patent Office (EPO) is a post-grant, contentious, '' inter partes'', administrative procedure intended to allow any European patent to be centrally opposed. European patents granted by the EPO under the European Patent Convention (EPC) may be opposed by any person from the public (no commercial or other interest whatsoever need be shown). This happens often when some prior art was not found during the grant procedure, but was only known by third parties.

An opposition can only be based on a limited number of grounds,"The function of Article 100 EPC is to provide, within the framework of the EPC, a limited number of legal bases, ie a limited number of objections on which an opposition can be based." i
Decision G 1/95 (19 July 1996)
reasons 4.1. i.e. on the grounds that the subject-matter of the patent is not patentable, that the invention is insufficiently disclosed, or that the content of the patent extends beyond the content of the application as filed. The notice of opposition to a European patent must be filed in writing at the EPO (either at Munich, The Hague or Berlin), along with the payment of an opposition fee, within nine months from the publication of the mention of the grant of the patent in the European Patent Bulletin. Opposition Divisions of the EPO are responsible for the examination of oppositions. The opposition procedure may involve multiple opponents. According to the EPO, a European patent was once opposed by a record number of 27 opponents.

Purpose, framework, and available grounds

The purpose of the opposition proceedings is to give opponents, such as competitors, the opportunity to challenge the validity of a granted European patent. Opponents may also challenge only some of the claims of the European patent (although this is in practice rather unusual), therefore limiting the framework of the opposition to the challenged claims.

However, an opposition can only be based on a limited number of grounds (i.e., objections) specified in the European Patent Convention, namely the grounds listed in . An opposition can be based on the grounds that the subject-matter of the patent is not patentable (Article 100(a) EPC, for instance because the claimed invention is not new or not inventive), on the ground that the invention is insufficiently disclosed to allow a person skilled in the art to carry it out (Article 100(b) EPC), or on the ground that the content of the patent extends beyond the content of the application as filed –"or, if the patent was granted on a divisional application or on a new application filed under , beyond the content of the earlier application as filed"– (Article 100(c) EPC). An opposition can for instance not be validly based on the grounds that the invention lacks unity () or that the right to the European patent does not belong to the proprietor of the patent ().

Filing and admissibility

Before starting the substantive examination of the opposition, the Opposition Division examines whether the opposition must be considered as filed ("Is there an opposition?") and whether it is admissible ("Is the opposition admissible?"). The Opposition Division may find that the opposition is not deemed to have been filed, for instance because the opposition fee has not been paid within the nine-month opposition period, because the notice of opposition is not signed, or because the notice is not in an accepted language.

In order for an opposition to be admissible it must meet the provisions of
* , i.e. a notice of opposition must be filed by a natural or legal person within nine months from the publication of the mention of grant of the European patent in the European Patent Bulletin (the start of the nine-month opposition period depends on the publication of the mention of grant of the European patent in the European Patent Bulletin, not on the publication of the specification of the European patent), and
* , i.e. the notice of opposition must contain a statement of the extent to which the European patent is opposed and of the grounds on which the opposition is based, as well as an indication of the facts and evidence presented in support of these grounds.

In addition, an opposition is also rejected as inadmissible if it fails to meet the requirements of after the opponent was invited to remedy to these failures within a given time limit. If the opposition is not admissible, the opposition is rejected under .

Inadmissible oppositions and oppositions which are deemed not to have been filed are not substantively examined (no examination on the merits). An opposition can only be rejected as inadmissible if the opposition has been first deemed to have been filed, and, if it is deemed to have been filed, the opposition exists, even if later the opposition is rejected as inadmissible. If an opposition is deemed not to have been filed, any opposition fee which has been paid is refunded. In contrast, if an opposition is rejected as inadmissible, an already paid opposition fee is not refunded.

Straw man

An opposition may be filed by a straw man to conceal the identity of the party actually interested in having the patent revoked. A strawman is "a party acting on behalf of another person." In 1999, the Enlarged Board of Appeal held that the use of a straw man did not render the opposition inadmissible unless "the involvement of the opponent is to be regarded as circumventing the law by abuse of process."

Filing of an opposition in common by a group of persons

An opposition may be jointly filed by more than one natural or legal persons.: "Entitlement to oppose" Such an opposition is admissible upon payment of a single opposition fee. It must, however, be "clear throughout the procedure who belongs to the group of common opponents".

Substantive examination

If the opposition is admissible, the Opposition Division examines the grounds for opposition as to their merits. In that examination, the Opposition Division is not limited "to the facts, evidence and arguments provided by the parties and the relief sought" but it examines "the facts of its own motion". The Opposition Division may even, of its own motion, raise a new ground for opposition that the opponent(s) did not raise in their notice of opposition. The Opposition Division may do so "if there are clear reasons to believe that such grounds are relevant and would in whole or in part prejudice the maintenance of the European patent", the underlying aim being to avoid "the maintenance of European patents which are invalid". The patent proprietor also has the opportunity to reply to the grounds of opposition. That is, the proprietor may submit arguments and, to a certain extent, amendments in reply thereto.

Thus, in view of the grounds of opposition, and in view for instance of a prior art document introduced into the proceedings by the opponent, the proprietor may amend the patent, i.e. the description, claims, and drawings thereof, although amendments may not be filed as of right at any stage during the opposition proceedings. The patent proprietor is master of its own patent in that the decision to amend or not, and how to amend the patent, is a decision of the proprietor alone (although the Opposition Division or the opponent may apply pressure to have amendments made).Decision T 1099/06
Reasons 6. The patent, however, may not be amended in such a manner that the amendment would lead to an extension of the protection conferred by the patent.

If amendments are made to the patent during the opposition proceedings, the patent (and the invention to which it relates) must meet the requirements of the EPC. These requirements notably include the requirements of support in the description and clarity (), even though those are not listed as grounds of opposition in . However, the requirements to be met by the amended patent do not include the requirement of unity of invention (because divisionals cannot be filed after grant).

During the opposition, oral proceedings may take place at the request of the EPO or at the request of any party to the proceedings, i.e. the patentee or an opponent. The oral proceedings are held before the Opposition Division itself. They are held in Munich, the Hague or Berlin, and are public unless very particular circumstances apply. This contrasts with oral proceedings held before an Examining Division, which are not public. The list of public oral proceedings in opposition before the EPO is available on its web site. The right to oral proceedings is a specific and codified part of the procedural right to be heard. A decision is generally pronounced at the end of the oral proceedings, with reasons to follow in writing.

Outcome and effects of the opposition

The opposition proceedings may have one of three outcomes:
* The patent is maintained as granted. This is the outcome if the opposition is rejected or if the Opposition Division decides to discontinue the opposition proceedings. The Opposition Division may decide to discontinue the opposition proceedings notably if the sole opposition or all the oppositions have been withdrawn and the patent proprietor is therefore the only remaining party to the proceedings. The withdrawal of an opposition may result from a settlement reached between the proprietor and the opponent. The opposition proceedings may also be discontinued " the European patent has been surrendered in all the designated Contracting States or has lapsed in all those States".
* The patent is maintained in an amended form. In this case, a new patent specification is published.
* The patent is revoked. This is the most successful outcome for the opponent, although the maintenance of a patent in an amended form may also be regarded as a success.

The opposition has effect on all designated states in the European patent. Decisions by Opposition Divisions, like any other final decisions of first instance divisions, are appealable.

A decision of the EPO to revoke a European patent is final (when the opportunity to appeal before the EPO is exhausted), which makes the opposition proceedings at the EPO especially attractive for opponents.Malwina Mejer, Bruno van Pottelsberghe de la Potterie
"Economic Incongruities in the European Patent System"
ECARES working paper 2009‐003, January 2009. In contrast, a decision of the EPO not to revoke a European patent (the decision instead maintaining the patent as granted or in an amended form) leaves the way open for revocation by the national court. The EPO decision does not create an estoppel precluding a subsequent challenge by an unsuccessful opponent at the national level (at least before the English courts).008