Following grant of a European patent, third parties wishing to challenge the grant may file an opposition at the European Patent Office (EPO) within a nine-month window. EPO opposition proceedings are a powerful tool, being highly cost-effective, with no institution hurdle to overcome, and still the only mechanism available for achieving revocation of a European patent in its entirety, for all countries, in a single action. However, current timescales to reach a decision compare unfavorably with those in other fora, such as inter partes reviews (IPRs) and post-grant reviews (PGRs) before the U.S. Patent and Trademark Office's (USPTO) Patent Trial and Appeal Board (PTAB) and revocation proceedings in the soon-to-open Unified Patent Court (UPC) in Europe: procedural delays in processing oppositions mean typical time frames of two years or longer before first-instance decisions are reached. However, under the EPO’s “Early Certainty” streamlining drive, details of which have recently been announced, standard opposition cases filed from July 1, 2016 should now be decided at first instance within fifteen months from the end of the nine-month opposition-filing window. The modified opposition procedure should prove beneficial to third parties by helping to provide legal certainty in a more timely manner, but will place additional pressure on patent proprietors who may need to prepare their defenses more quickly.


While a European patent granted by the EPO is a bundle of national patents that need to be maintained and managed separately,1 within a nine-month window following grant2, it may be attacked as a whole—for all of the states it covers, no matter where validated—in a single action by means of opposition proceedings centrally at the EPO. An opposition may be filed on grounds related to exclusions/exceptions from patentability,3 novelty,4 inventive step,5 industrial applicability,6 added subject matter7, and/or insufficiency.8 On average, of the 5% of European patents opposed, around 30% are revoked (cancelled, as if they never existed); around 40% are maintained in amended form (typically with the independent claims being limited to overcome prior art or other objections); and around 30% are maintained as granted (i.e., the opposition is rejected).9 That equates to around 70% of European patents that are opposed being at least wounded, if not killed off completely.

An EPO opposition offers a number of advantages and can be a powerful weapon for a third party wishing to challenge the grant of a European patent:

  • it is the only forum in which the whole patent may be attacked and revoked;
  • its success rate in wounding or killing patents is high;
  • it is a relatively inexpensive procedure;10
  • there is no limit on the number of pages or arguments that may be submitted, so an opponent can try out different arguments and attacks, which may help with envisaged IPR/PGR proceedings;
  • the written submissions and official communications/decisions all appear on the EPO’s public file, so an opposition can be a useful way to obtain public statements on the meaning and scope of a European patent and/or the prior art;
  • it can force disclosure of documents to the USPTO on corresponding U.S. cases; and
  • there is effectively no institution standard or hurdle to overcome—provided that at least one reasoned ground of opposition has been presented, an opposition will be deemed admissible, no matter how strong or weak the arguments presented may be.

While these positive attributes of the EPO’s opposition procedure are significant and appealing, one aspect that is viewed less favorably is the length of time typically elapsing between opposition filings and oral proceedings, i.e., how long it is generally taking for the EPO to decide on oppositions. According to the EPO’s 2015 annual report, the average duration of the opposition procedure was 26.1 months, up from 25.5 months in 2014.11 In contrast, once instituted, IPRs and PGRs at the PTAB must be completed within twelve months (with a six-month extension possible for good cause);12 and at the soon-to-open Unified Patent Court (UPC), revocation actions are expected to follow a timeline from the filing of a revocation claim to the handing down of the written decision of less than fourteen months.13 First-instance EPO opposition decisions are therefore taking a year or so longer than before these panels, which is clearly undesirable for parties wishing to know the legal standing of a European patent.

One reason behind the slow handling of oppositions is down to staffing pressures at the EPO, but it is also contributed to by patent proprietors and opponents legitimately requesting extensions of time when responding to notices of opposition or subsequent replies during the written procedure. Typically, an extension of time of two months will be granted automatically at present. Further extensions of time must be justified, but it is not uncommon for further extensions of two or more months to be allowed where an opposition case is complex or involves multiple opponents.

New Procedure

The EPO announced an “Early Certainty” streamlining drive two years ago, aimed at speeding up the search phase for European patent applications, to help clear the backlog of cases at the EPO. This drive has been successful and the backlog is expected to have been cleared shortly, so the EPO has now announced an expansion of the streamlining drive to other areas of the patenting process, including oppositions.14

The newly announced aim is that “standard” or “straightforward” opposition cases filed from July 1, 2016, should be decided at first instance within fifteen months from the end of the nine-month opposition-filing window. Against current timescales, this should have the effect of reducing the time taken for a decision to be reached in an opposition by around a year on average.

It should be noted that the new, streamlined procedure will only apply to oppositions that are considered to be “standard” or “straightforward”. However, it is not yet clear how the EPO will decide whether an opposition is standard or nonstandard. Some factors that it is understood will be determinative, though, include the number of opponents and the type of evidence being relied upon in the opposition: cases with more than one opponent are expected to be considered to be nonstandard and therefore not subject to the new, streamlined procedure, as are cases where evidence of public prior use is submitted in attacking the patentability of the claims. It can be appreciated that the level of work involved for the EPO in considering—as well as for the patent proprietor in defending—a multi-opponent opposition and/or an allegation of public prior use (especially if witnesses are to be involved) is typically higher, so the streamlined procedure would likely be inappropriate in such cases. Since the majority of oppositions are by a single opponent and arguments over public prior use are rare, it would appear that most cases15 will be processed under the streamlined procedure.

The EPO has indicated that it will shorten the duration of oppositions by streamlining practices and procedures with regard to both its own internal handling and processing of oppositions and the procedural interactions with the parties involved.

Under the current practice of the EPO, after the nine-month window for filing an opposition has closed, the EPO invites the proprietor to respond to the opposition within a four-month term, but this term may be freely extended by two months, and in some cases even further. Under the new procedure, extensions to the initial four-month term for the proprietor’s reply will be allowed by the opposition division in exceptional cases only. For proprietors in some technology areas, this will have a significant impact on the handling of oppositions in future as it will shorten the typical time available for preparing responses by up to a half, or even more.

No specific guidance has yet been issued as to what circumstances might be considered to be exceptional and therefore warranting a two-month extension. Looking at the EPO’s Guidelines for Examination, however, there is a useful discussion of the circumstances under which exceptional requests for extensions of time during the examination phase of a European patent application may be allowed: “when the reasons given are sufficient to show convincingly that a reply in the period previously laid down will not be possible. Such exceptional circumstances might be e.g. the fact that a representative or client is so seriously ill that he cannot deal with the case in time; or the need to perform extensive biological experiments or tests. On the other hand, foreseeable or avoidable circumstances (e.g. leave, pressure of other work) should not be accepted as a sufficiently exceptional circumstance.”16 It would be reasonable to expect that a similar approach will apply to the exceptional allowance of requests for extensions under the new streamlined procedure for oppositions. As such, with the likelihood of obtaining extensions of time being very low, proprietors should from now on plan to have opposition replies prepared and ready to file within the initial four-month term set by the EPO. The reply should be a full response to the opposition, i.e., all of the facts, evidence, and arguments in support of the case, and any amendments to the patent, should be submitted within this time limit.

Once the proprietor has filed a reply to the opposition, a copy of the reply is immediately sent to the opponent. This will be for the opponent’s information only and will not include an invitation to the opponent to submit any comments on the reply. If, however, the opponent does file comments on his/her own initiative, they will be incorporated into the proceedings and considered by the opposition division.

It is at this stage that the principal streamlining of the EPO’s internal procedures will take place. Whereas, in the past, opposition divisions have been known to sit on oppositions for between six months and two years before considering them and issuing summonses to oral proceedings, under the new procedure, a summons should be issued within three months. This represents a significant shortening of the EPO’s evaluation process and will lead to oral proceedings—and therefore decisions—being reached much faster than at present.

The summons specifies the date on which the oral proceedings are to take place and, as a rule under the new procedure, it will be at least six months after dispatch of the summons. The summons also fixes a final date for the parties to file written submissions and any amendments, and this will normally be set at two months before the oral proceedings.

As is currently the case, the summons will continue to include a communication setting out the issues that the opposition division wishes to discuss at the oral proceedings and the opposition division’s provisional and nonbinding opinion on the arguments put forward by the parties and any amendments submitted by the proprietor. Thus, providing at least six months’ notice of the oral proceedings date should ensure that there is sufficient time for the parties to react to the summons and prepare further arguments and/or amendments ahead of the oral proceedings.

On the day of the oral proceedings, the decision of the opposition division is announced at the end, after the parties have presented their arguments and the proprietor has submitted any further amendments to the patent. With the new streamlined procedure announced by the EPO, this process—from the end of the opposition-filing window through to the day of the oral proceedings—is expected to last only fifteen months.

Of course, the decision announced at the oral proceedings is a first-instance decision and this is subject to appeal to the EPO’s Boards of Appeal. It should be noted that the Boards of Appeal are independent and not bound by the new streamlining initiative, so some critics might argue that this could simply lead to cases reaching the appeal stage sooner and merely increasing the already sizeable backlog at the Boards of Appeal. It is not uncommon for an appeal at the EPO to take three or more years to reach a final decision. However, not all cases are appealed and the new streamlining initiative will be of significant benefit in providing legal certainty for the proprietor, the opponent, and the public in general on all those cases for which the first-instance decision is the final decision.


The EPO’s new streamlining initiative will be effective for oppositions filed from July 1, 2016, onwards. The EPO’s aim is to process oppositions, from the end of the nine-month opposition-filing window through to oral proceedings where the decision is made, within fifteen months. This streamlined procedure will apply to all straightforward/standard oppositions, but not where there are multiple opponents or public prior use evidence is at issue.

In order to ensure that oppositions can be processed according to this shortened time frame, opponents should ensure that they present their full case promptly from the outset, and proprietors should ensure that their reply to an opposition is a full and complete response, including amendments to the patent where appropriate. The opportunity to file a final set of submissions (arguments and/or amendments, including auxiliary requests) will still be available to the parties in the lead-up to oral proceedings.

The modified opposition procedure should prove beneficial by helping to provide legal certainty in a more timely manner, and is therefore generally considered a welcome development from the EPO.