An opposition is a means of centrally challenging the validity of a European patent after grant. A successful opposition can revoke or limit the patent across all 39 member states, protecting your freedom to operate in multiple markets. An opposition can be filed at any time within 9 months following the mention of grant of the patent in the European Patent Bulletin. The opposition term is not extensible.

An opposition may be filed by any member of the public. Multiple oppositions can filed by different opposing parties. Anonymity can be achieved by filing using a strawman. 

Oppositions are handled by what is usually a three-member Opposition Division. The primary examiner from the examination procedure could be part of the Opposition Division. Opposition Division is technically qualified with expertise in the relevant subject matter.

An EPO opposition (and appeal) is effective in all EPO member states.  It is therefore a central attack that can achieve revocation in all EPO Contracting States where the patent is in force. This includes all EU states (and UP) and UK, Switzerland, Norway, Spain and Turkey. It also takes effect on any other rights based on the European patent (e.g. Hong Kong patents, SPCs).

An EPO opposition and appeal is typically lower in cost than national, or UPC, litigation. It therefore represents an extremely powerful and cost-effective tool.

The deadline for filing an opposition is 9 months after the date of grant. Once the opposition has been filed, the EPO will conduct a formal review. If the formal requirements are met and the opposition appears admissible, the notice of opposition will be forwarded to the patentee who will be given four months to file a response. No extension is available.

The patentee has the option to amend their patent and to file a number of auxiliary requests, which act as fall-back positions.

The notice of opposition and response to the notice of opposition should generally be as complete as possible, as facts, evidence and requests filed after the initial period for response may be deemed late filed, in which case they will be admitted only at the Opposition Division’s discretion. EPO Opposition practice favours written arguments, and ambushing the other party with new evidence or requests during the final hearing is discouraged. This means that the initial notice of opposition and response to the notice of opposition must be as comprehensive as possible.  

Following the patentee’s reply, the Opposition Division will issue a preliminary opinion on the key issues and invite the parties to a hearing.    

The parties may file further rounds of written submissions, either at the request of the Opposition Division or at their own discretion. All submissions made after the initial notice of opposition and reply are at risk of being deemed ‘late filed’ and not being admitted into proceedings. Despite this, given the preference for written procedure, it is often best to file submissions in writing rather than waiting and making the submissions at the oral hearing for the first time.  

Parties will have an opportunity to argue their case at an in-person or video conference hearing and a verbal decision will be announced on the day. The opposition procedure, from filing the notice of opposition to the decision being issued at the hearing, will typically take somewhere between 15-24 months.

Following the hearing, a written decision will be issued, normally within one to four months of the hearing. This written opposition decision can be appealed.

An opposition can be filed on three grounds:

• the claimed invention is not patentable (because the subject matter is excluded from patentability or because it lacks novelty or inventive step);
• the specification of the patent does not disclose the invention sufficiently clearly and completely for it to be carried out by a person skilled in the art ("insufficiency"), and
• the subject matter of the European patent extends beyond the content of the European application as originally filed ("added subject matter").

Clarity is not a ground for opposition, however it may become relevant if the patentee chooses to amend their patent. Unity is not a ground for opposition.

Decisions from Boards of Appeal (“T-decisions”) are generally not directly binding on Opposition Divisions or other Boards of Appeal; they do, however, act as a persuasive legal authority. Decisions of the Enlarged Board of Appeal (“G-decisions”) are almost always followed. Many key principles of European practice are determined based on case law (both “G decisions” and “T decisions”). Similarly, many important nuances of procedure are only set out in case law (not in the statutes or guidelines) and can only be understood from the relevant decisions.

There are many reasons to file an opposition and every situation is different. Some common reasons for filing an opposition include:

• to secure Freedom to Operate;
• to address licensing costs or concerns;
• in response to, or anticipation of, litigation;
• to maintain a competitive advantage;
• to prevent a competitor gaining an inequitable competitive advantage;
• to free up competition within a market;
• to achieve strategic commercial goals
   

Opposition costs vary and can be tailored to the technology, patent of interest and commercial objective. EPO opposition and appeal procedures will nearly always have lower costs than equivalent national Court or Unified Patent Court proceedings. However, even if successful, costs will rarely be awarded before the EPO. Expected costs must be balanced against potential commercial impact of the patent being enforced or used in its current form – e.g. loss of market share, interim injunction, litigation expenses…

An appeal is a review of a decision by the European Patent Office. An appeal has suspensive effect. Any party adversely affected by a decision can appeal. In an appeal from an opposition decision, all parties will become parties of right if any of the other parties files an appeal and can submit arguments. Only appealing parties can improve their position on appeal.

An appeal is based on “requests, facts, objections, arguments, and evidence on which the decision under appeal was based.” It is difficult to have any new requests, facts, objections, arguments or evidence admitted during the appeal process, it is therefore very important that anything that a party may wish to rely on in appeal is submitted during the opposition procedure, where possible. Opposition strategy must be considered with an eye on potential future appeal proceedings.

A notice of appeal must be filed within two months of notification of the contested written decision, with the relevant fee for appeal. Grounds of appeal, outlining the party’s complete case, must be filed within four months of notification of the written decision. The grounds of appeal are forwarded to the other parties who are given four months to file a reply to the statement of grounds.  

Further submissions may be filed at any time, but any amendments to a party’s case are only admitted at the discretion of the Board. It is difficult to have amendments to a case admitted and the Board applies an increasingly stringent approach to admitting amendments as the appeal progresses.

The Board will issue a summons to oral proceedings. The hearing may be in person, or by videoconference. The Board will also issue a communication drawing attention to matters that seem to be of particular significance for the decision to be taken. This communication may include a preliminary opinion.

The Board decision will be communicated at the hearing. A written decision will follow, typically within one to four months.

Enlarged board referrals normally arise when there is a specific question on the interpretation of the law that needs to be addressed. The main task of the enlarged board is to ensure uninform application of the EPC. A referral can arise based when a normal board of appeal is unable to answer a question on a point of law, or if several appeal boards have made contradicting decisions and the president decides the refer the point for review. It is not something that a patentee or opponent can request themselves.

Enlarged board decisions are rare, only a couple a year at maximum, but they have they a huge impact on how particular aspects of the law should be interpreted. As a result, they can fundamentally change not only the outcome of single case but how future oppositions are decided.

The enlarged board of appeal also handles petitions for review. A petition for review is a judicial review of board of appeal’s decision. However, it is not a further chance to appeal the substantive aspects of the patent’s validity. Petitions for review are instead designed to protect parties who have been disadvantaged by the conduct of a Board. Petitions for Review are only available if it can be shown that certain strict criteria arise, such as a fundamental violation of a parties right to be heard or a fundamental procedural defect.