PROFESSIONAL SERVICE
EPO OPPOSITIONS
The EPO allows third parties to challenge its decision to grant a European patent for a short period of time after that patent has been granted. If successful, an opponent may convince the EPO to revoke the patent, or at least get the proprietor to amend it, which can be vital for the opponent’s commercial strategy. EPO opposition proceedings are much cheaper than challenging validity of a patent in the courts, and the result of the opposition proceedings takes effect in all of the European countries in which the patent has effect. This means EPO oppositions are very attractive to those wishing to have a European patent invalidated.
To oppose a European patent, the opponent has to present its case to the EPO within 9 months of the grant date of the patent. The EPO will then give the proprietor of the patent an opportunity to respond within about 4 months of being informed that an opposition has been filed. The EPO’s Opposition Division will then consider the arguments put forward by each side, and will usually then issue its preliminary, non-binding opinion on the pertinent issues. In many cases, both sides will then be set a deadline for filing further written arguments and evidence, and there will normally then be an oral hearing for both sides to present their arguments to the Opposition Division directly. The Opposition Division will then decide on the matter, and a written decision (i) maintaining the patent as granted, (ii) maintaining the patent in amended form, or (iii) revoking the patent altogether will be issued shortly afterwards.
Whilst the exact time EPO oppositions take to complete can vary depending on the complexity of the case and the number of parties involved, an approximate timeline for these types of proceedings is illustrated below.
We have a wealth of experience in oppositions before the EPO, both in terms of defending our clients’ patents from attacks by opponents and attacking the patents of our clients’ competitors. Our team is accustomed to handling high-value, complex proceedings and is, for example, currently involved in attacking a collection of highly valuable, cutting-edge life sciences patents relating to the revolutionary gene-editing technology known as CRISPR/Cas9.
If there is a European patent that you want revoked, then we would be happy to work with you to file an opposition at the EPO. Similarly, if your European patent is under attack from your competitors and you would like our help defending it, then we would be happy to work with you to fend off that opposition, as well.
EPO oppositions can be filed anonymously, and thus if you are concerned about your competitors learning that their European patent is problematic for you, then we can file the opposition in our name, avoiding the need to identify you at any stage.
MOST EPO OPPOSITIONS FOLLOW THE SAME PROCESS
EPO OPPOSITIONS TIMELINE
0
Months
European Patent Granted
9
Months
Opposition Filed
10
Months
EPO Invites Proprietor to Respond
14
Months
Proprietor Files Response
17
Months
EPO Issues Summons and Preliminary Opinion
19-25
Months
Deadline for Making Final Written Submissions
20-27
Months
Oral Proceedings and Verbal Decision
24-33
Months
Written Decision Issued
PROFESSIONAL SERVICE
EPO APPEALS
Sometimes, the EPO’s Examining Division may refuse one of your European patent applications, or the EPO’s Opposition Division may reach a decision that is not in your favour. Fortunately, those adverse decisions can be appealed to the EPO’s Boards of Appeal, where you have an opportunity to have that decision overturned. Convincing the Boards of Appeal to overrule the Examining and Opposition Divisions is no easy task but, with our team’s technical and legal know how and years of experience representing clients in these types of proceedings, we have handled a large number of EPO appeal cases with successful outcomes.
To appeal a decision of the EPO, the appellant must file notice of that appeal within 2 months of the decision being issued. Within 4 months of the decision being issued, the appellant has to set out the grounds on which its appeal is based. In the case of appeals arising from opposition proceedings, the EPO will then notify the other side that an appeal has been filed, giving the other side approximately 4 months to file a submission in response. Typically, the EPO will then issue a preliminary, non-binding opinion on the arguments presented, and will summon the parties to an oral hearing to present those arguments further. A decision will be taken on the matter at the oral hearing, and written reasoning for that decision will then be issued by the Board of Appeal within the next few months.
We frequently represent clients who want to appeal a decision of the EPO that hasn’t gone their way and, with our team’s specialist expertise regarding a variety of different technologies, we are well-placed to help you challenge a decision that has gone against you, too.
Recent Insights
Read the latest insights from the Schlich team reporting recent cases and updates from the EPO.
G 1/23 confirms that products placed on the market before the effective date of a European patent application constitute prior art, regardless of whether they can be reproduced
On 2 July 2025, the EPO’s Enlarged Board of Appeal (EBA) issued its decision in G 1/23. The referral stemmed from T 0438/19, an appeal against the decision of an opposition division to reject an opposition against a European patent directed to a material for encapsulating a solar cell which comprises an ethylene/alpha-olefin copolymer with certain defined properties, including a content of aluminium element of from 10 to 500ppm. D1 disclosed a commercially available copolymer, ENGAGE® 8400, which the opponent/appellant sought to rely on as the closest prior art for their inventive step challenge; however, the Patentee argued, with reference to G 1/92, that ENGAGE® 8400 cannot be reproduced (i.e., it is not enabled) and therefore it has not been made available to the public within the meaning of Article 54(2) EPC and thus is not a suitable starting point for the assessment of inventive step. Grappling with how to interpret G 1/92, the Board in T 0438/19 referred three questions to the EBA focused on understanding whether a commercial product, put on the market before the filing date of a European patent application, can be excluded from the state of the art for the sole reason that it could not be reproduced. The EBA has now answered, and the short answer is no!
Going it Alone: The EPO Chooses a Different Path to Claim Interpretation to the Courts
Many of us thought G 1/24 would convince the EPO to change its approach to claim interpretation, however a few recent decisions of the EPO’s Boards of Appeal and at least one commentary regarding the EPO’s official guidance to its examiners suggest the EPO’s practice of interpreting the claims in isolation may be here to stay. The EPO thus appears to be taking a different approach to claim interpretation to the national courts and the UPC, despite the Enlarged Board of Appeal stating in G 1/24 that it considered such an idea “a most unattractive proposition”.
New Referral to the Enlarged Board of Appeal: The Description Amendment Saga Goes On!
The question of legal basis for the EPO’s description amendment requirement has been the subject of debate for a long time. However, a recent referral to the Enlarged Board of Appeal (G 1/25) has set the stage for finally settling this matter.
EPO’s Enlarged Board of Appeal Issues Much-Anticipated Decision in G 1/24
The question of whether and, if so, the extent to which the description and drawings should be used to interpret the claims of a European patent / European patent application has been a hotly contested topic in the world of IP for a considerable length of time. In its recent decision in G 1/24, the Enlarged Board of Appeal has finally settled the issue, holding that the description and drawings must always be used to interpret the claims. This decision thus brings EPO practice into line with the practice of the national courts of the EPC contracting states and the UPC.
Use Claims Can be Method Claims in Disguise, says the EPO
Strict rules of interpretation apply to the four categories of claim permitted by the EPO (product, method, apparatus, and use). It is usually clear from the claim wording which claim category is used to define an invention, however a recent decision from one Board of Appeal has confirmed that, in certain cases, claims initially appearing to be use claims are, in fact, to be interpreted as method claims.
When it comes to Post Filed Data, the Earlier the Better – A Brief Reminder Following G 2/21
This recent decision of the EPO Boards of Appeal, T 1865/22, reminds applicants to include clear details of the claimed technical effect in the application as filed and to file evidence in support of said technical effect as early as possible
Is an Intervener an Opponent or Appellant, or just an Intervener?
A new referral has been made to the Enlarged Board of Appeal relating to the question of whether an appeal can continue with an intervener only, if the appellant has withdrawn.
What Satisfies the Palate of the EPO’s Boards of Appeal? Fish Oil and Fruit Juice, Apparently…
In a recent decision, the EPO’s Boards of Appeal have confirmed the importance of filing data to support arguments relating to sufficiency of disclosure in EPO opposition proceedings. The patent concerned related to a mixture of fish oil and fruit juice which was alleged to have anticancer properties. The opponent argued the constituents required to achieve the anticancer effect were not sufficiently disclosed, but failed to provide enough data to convince the Board of Appeal. Hence, the Board was satisfied the claimed composition was sufficiently disclosed and ordered that the patent be maintained in amended form.
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Our team of UK and European Patent Attorneys and Chartered Trade Mark Attorneys are highly knowledgeable and experienced in assisting clients with all aspects of their IP needs.
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