Can a Patent Grant Be Challenged? Romania 2026, Nullity Grounds, OSIM, Courts & UPC Revocation

Can a patent grant be challenged in Romania? The short answer is yes, and in 2026, rights-holders and competitors have more routes available than ever before. Romanian law provides two domestic tracks (an administrative procedure before OSIM and a judicial nullity action before the national courts), while the European patent system adds the EPO opposition window and, since Romania’s accession to the Unified Patent Court on 1 September 2024, the option of UPC central revocation for eligible European patents. This guide maps every available forum, explains the statutory nullity grounds, sets out step-by-step timelines and costs, and offers a strategic framework for choosing the right path.

Executive Summary, Short Answer

Yes, a granted patent can be challenged in Romania through multiple proceedings. For Romanian national patents, the challenger may file an administrative cancellation request with OSIM (the Romanian State Office for Inventions and Trademarks) or bring a nullity action before the specialised intellectual-property courts. For European patents (EPs) validated in Romania, the same national routes apply to the Romanian designation, but an EPO opposition may also be filed within nine months of grant.

Since 1 September 2024, Romania is part of the Unified Patent Court system. This means classical EPs that have not been opted out, and European patents with unitary effect, can be attacked through a UPC central revocation action that, if successful, invalidates the patent across all participating member states in a single proceeding.

The critical strategic question is therefore not whether a patent can be challenged, but where to challenge it.

Quick Checklist, Choose the Right Forum

Use the decision triggers below to identify your starting point. The patent type determines which forums are available:

• Romanian national patent (granted by OSIM). File an OSIM administrative cancellation request or bring a nullity action before the Romanian courts. UPC jurisdiction does not apply.
• European patent validated in Romania (classical EP, not opted out). All three options are available: Romanian national nullity, EPO opposition (if within the nine-month window), or UPC central revocation.
• European patent validated in Romania (classical EP, opted out of UPC). Romanian national nullity or EPO opposition only. UPC revocation is blocked for the duration of the opt-out.
• European patent with unitary effect covering Romania. UPC central revocation is the primary route (exclusive competence of the UPC). National nullity is not available for the unitary part.

Industry observers expect the choice between UPC central revocation vs national nullity to become the defining tactical decision for patent challengers operating in Romania throughout 2026 and beyond.

Grounds to Challenge a Patent in Romania, Statutory and Common Grounds

Statutory Nullity Grounds Under Romanian Patent Law

Romanian patent law sets out exhaustive grounds on which patent invalidation in Romania may be sought. The principal patent nullity grounds Romania recognises include:

• Lack of novelty. The claimed invention was part of the state of the art, publicly available anywhere in the world, before the priority date.
• Lack of inventive step. The claimed invention would have been obvious to a person skilled in the art, having regard to the state of the art at the priority date.
• Insufficient disclosure. The patent specification does not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art.
• Non-patentable subject matter. The patent covers subject matter excluded from patentability (e.g., discoveries, mathematical methods, aesthetic creations, methods of treatment of the human body by surgery or therapy, or plant and animal varieties).
• Extension beyond the original filing. The patent claims extend beyond the content of the application as originally filed.
• Prior rights (entitlement). The patent was granted to a person who was not entitled to it under the applicable rules on inventorship and ownership.

These grounds mirror the invalidity framework used by the EPO for European patents and are broadly consistent with Article 138 of the European Patent Convention.

Evidence Types and Practical Examples

Successful challenges typically rely on the following categories of evidence:

• Prior art documents. Published patents, scientific articles, product catalogues, or internet archive captures predating the priority date. A well-constructed prior-art search, conducted through commercial databases and OSIM’s own registry, is the foundation of any novelty or inventive-step attack.
• Expert technical reports. Romanian courts regularly appoint judicial experts, but parties also submit private expert reports. These must address both the claim construction and the comparison with cited prior art on a claim-by-claim basis.
• Technical comparisons and demonstrations. In some cases, physical demonstrations, laboratory analyses, or reverse-engineering reports are used to show that a product or process on the market before the priority date anticipates the patent claims.

Example 1, novelty attack: A competitor identifies a published university thesis, publicly accessible before the patent’s priority date, disclosing identical process steps. Filed with a certified translation and archive certificate, this prior art destroys novelty of the independent claim.

Example 2, insufficient disclosure: A pharmaceutical patent fails to include reproducible experimental data for a key dosage range. The challenger commissions independent laboratory tests showing the claimed effect cannot be reproduced based on the patent specification alone.

Example 3, inventive step (combination attack): Two published patent documents, each disclosing different features of the claimed invention, are combined to argue that a person skilled in the art would have arrived at the claimed combination without inventive effort. This is the most common type of invalidity argument in Romania, mirroring EPO problem-solution approach practice.

Administrative Route, OSIM Patent Cancellation and Corrections

OSIM Cancellation Procedure

OSIM handles administrative requests for cancellation or correction of granted Romanian national patents. This route is distinct from the judicial nullity action and is governed by the procedures published on the OSIM official website.

Key features of the OSIM patent cancellation process:

1. Who can file. Any interested party may file a request. There is no requirement to demonstrate a commercial interest or pending infringement dispute, although providing context strengthens the request.
2. Filing requirements. The request must identify the patent, specify the ground(s) for cancellation, and be accompanied by supporting evidence (prior art, technical analysis). An official fee is payable at the time of filing.
3. Examination. OSIM reviews the request on its merits. The patent holder is notified and given an opportunity to respond, including by filing observations or amending claims where permissible.
4. Decision. OSIM issues a reasoned decision. If cancellation is ordered, the patent is treated as if it had never been granted (retroactive effect, ex tunc).
5. Appeal. OSIM decisions may be appealed before the competent Romanian courts.

Practical Evidence Checklist for OSIM Filings

• Certified copies of prior-art publications with translations into Romanian where required.
• A technical comparison table mapping the prior art against each independent claim.
• A search report from a professional patent search provider (commercial databases, OSIM registry, EPO Espacenet).
• Any witness statements or declarations from technical experts attesting to the state of the art.
• Proof of payment of the OSIM administrative fee.

The OSIM route is generally faster and less costly than judicial nullity, making it an attractive first option for straightforward cases, particularly where strong prior art is readily available. However, OSIM’s procedural resources are limited compared to the courts, and complex factual or legal disputes may be better suited to judicial proceedings.

Judicial Route, Romanian Courts and National Nullity Actions

Which Courts Handle Patent Nullity?

Patent nullity actions in Romania are heard by the Bucharest Tribunal (Tribunalul București) as the court of first instance, which has specialised intellectual-property sections. Appeals are heard by the Bucharest Court of Appeal (Curtea de Apel București). This centralised structure ensures that judges handling patent disputes develop relevant technical and legal expertise.

Who Can File Patent Nullity in Romania

Under Romanian law, any interested person may file a nullity action. In practice, claimants are typically competitors facing infringement assertions, licensees disputing the scope of a licence, or third parties seeking freedom to operate. The state, through the public prosecutor, may also request nullity in the public interest, although this is rare. There is no time limit for filing a nullity action, it may be brought at any point during the life of the patent.

Pleadings, Evidence Standards and Interim Measures

The claimant must file a statement of claim identifying each ground of nullity and providing supporting evidence. Romanian courts apply a de novo assessment: they are not bound by OSIM’s earlier examination and will independently evaluate novelty, inventive step and other grounds.

Key procedural points for patent invalidation in Romania:

• Expert evidence. The court will typically appoint a judicial expert in the relevant technical field. Parties may also nominate their own party-appointed experts. Expert reports carry significant weight in Romanian patent litigation.
• Claim construction. Courts assess claims as understood by a person skilled in the art, taking account of the description and drawings. The prosecution history (file wrapper) at OSIM or the EPO may also be considered.
• Interim measures. While interim injunctions are more commonly associated with infringement proceedings, a defendant in an infringement case can raise nullity as a defence and, in certain circumstances, seek suspension of infringement proceedings pending the outcome of a nullity counterclaim.
• Remedies. If the court finds the patent invalid, it declares nullity ab initio, the patent is deemed never to have existed. Partial nullity (invalidation of specific claims while maintaining others) is also possible where the remaining claims are independently valid.

Typical Timelines for Court Proceedings

First-instance nullity proceedings before the Bucharest Tribunal typically last between 12 and 24 months, depending on complexity and the need for expert evidence. Appeals before the Bucharest Court of Appeal add a further 6 to 18 months. Total duration from filing to final, non-appealable decision therefore ranges from approximately 18 to 42 months. These estimates are consistent with timelines reported in the Romania country guide published by Stoica & Asociatii for Legal 500.

European Routes: EPO Opposition, EP Validation and UPC Central Revocation

EPO Opposition vs National Nullity

Any third party may file an opposition against a European patent at the European Patent Office within nine months of the date of grant. An EPO opposition can result in the patent being revoked, maintained in amended form, or maintained as granted, and the outcome applies to all designated states, including Romania. This is a powerful centralised remedy, but the strict nine-month window means it is only available shortly after grant.

If the nine-month opposition period has expired and no opposition was filed (or an opposition was unsuccessful), the only routes to challenge the patent in respect of Romania are national nullity or, for eligible patents, UPC central revocation.

EP Validation in Romania, Nullity Strategies

A European patent validated in Romania takes effect as a Romanian national patent for the territory of Romania. This means that EP validation Romania nullity actions follow the same procedural rules as those for purely national patents: they are brought before the Bucharest Tribunal or initiated at OSIM. The grounds mirror those available under the EPC (Article 138) and Romanian patent law. A successful national nullity action removes the patent’s effect in Romania only, it has no impact on other designated states.

UPC Central Revocation, Scope, Jurisdiction and Romania’s Position

Since Romania joined the Unified Patent Court on 1 September 2024, as confirmed by Reddie & Grose, classical European patents that have not been opted out of the UPC system, and European patents with unitary effect, fall within the UPC’s jurisdiction for patent revocation Romania proceedings. A revocation action filed at the UPC Central Division, if successful, invalidates the patent across all UPC member states simultaneously.

The UPC’s own FAQ on jurisdiction confirms that during the transitional period, actions for revocation of classical EPs may be brought either before the UPC or before national courts. However, for European patents with unitary effect, the UPC has exclusive competence, national courts (including Romanian courts) have no jurisdiction over unitary patents.

The practical comparison below summarises the three European-level forums:

Strategic Interplay: Multi-Forum Strategies and Risks

Opt-Out Implications and Risks

Patent holders may opt out classical EPs from the UPC system to prevent central revocation. However, an opt-out also prevents the patent holder from using the UPC for enforcement. From the challenger’s perspective, an opted-out EP can only be attacked through national nullity or EPO opposition, meaning the challenger must pursue country-by-country litigation if the patent is validated in multiple states. Detailed strategic analysis of opt-out decisions is addressed in the Bardehle Pagenberg unitary patent guide.

Parallel Proceedings and Lis Pendens

A challenger may face the question of whether to file at the UPC, at the Romanian courts, or both. Early indications suggest that the UPC will exercise jurisdiction even where parallel national proceedings exist, as illustrated by cases analysed by Pinsent Masons. This creates a risk of duplicative proceedings and potentially inconsistent outcomes. Careful coordination, including timing of filings and use of the lis pendens rules under the UPC Agreement, is essential.

Two-Track Strategy: Injunction Plus Nullity

A common tactical approach is to pursue a nullity action while simultaneously seeking (or defending against) an injunction. In Romania, a defendant accused of patent infringement can raise invalidity as a defence and file a counterclaim for nullity. This two-track approach is particularly effective where the challenger can demonstrate strong prior art: the prospect of patent invalidation may persuade the court to refuse or suspend an interim injunction, or to require the patent holder to post a security bond. Further guidance on injunction standards and security requirements is available in the companion article on patent injunctions Romania 2026.

Practical Timeline and Costs

The table below provides model timelines and indicative cost ranges for each forum. Actual timelines depend on case complexity, evidence requirements and court scheduling.

Cost estimates are expressed in relative terms because actual fees depend on the complexity of the technology, the number of prior-art documents analysed, expert fees and legal representation costs. OSIM official fees are published on the OSIM website; UPC court fees are set out in the UPC Rules of Procedure and scale with the value of the dispute.

Case Studies and Practitioner Tips

The following anonymised vignettes illustrate how the choice of forum shapes outcomes in practice.

Case A, OSIM cancellation success. A Romanian manufacturer identified a competitor’s national patent covering a commonplace mechanical assembly. A prior-art search revealed a published utility model from a third country, filed three years before the patent’s priority date, disclosing an identical mechanism. An administrative cancellation request to OSIM, supported by the prior-art document and a technical comparison, resulted in full cancellation within ten months.

Case B, UPC central revocation. A multinational company faced infringement assertions under a classical EP validated in twelve UPC member states, including Romania. Rather than defending country-by-country, the company filed a central revocation action at the UPC Central Division. The action targeted the patent’s inventive step, relying on a combination of two published scientific articles. The likely practical effect of this single proceeding was to remove the patent across all twelve states simultaneously, a result that would have required separate national actions in the absence of the UPC.

Case C, national court nullity denied. A competitor challenged an EP validated in Romania on grounds of insufficient disclosure. The Bucharest Tribunal appointed a judicial expert who concluded that, while the patent specification was terse, it contained enough information for a person skilled in the art to reproduce the invention. The nullity action was dismissed. The case underscored the importance of pre-filing assessment: insufficient disclosure is one of the harder grounds to prove, and expert evidence is decisive.

Five Tactical Dos and Don’ts

• Do conduct a comprehensive prior-art search before selecting a forum, the strength of available evidence should drive forum choice.
• Do check the opt-out register before assuming UPC jurisdiction is available for a classical EP.
• Do coordinate timing if pursuing parallel proceedings (e.g., EPO opposition and national nullity) to avoid inconsistent claim constructions.
• Don’t rely solely on insufficient disclosure as a ground unless you have strong experimental evidence, Romanian courts and OSIM apply a practical, skilled-person standard.
• Don’t delay: if the EPO opposition window is still open, it is almost always worth filing because it provides a central, binding result across all designated states.

Conclusion, Can a Patent Grant Be Challenged? Your Recommended Action Plan

For in-house counsel and IP managers evaluating whether a patent can be challenged in Romania in 2026, the following six-step action plan provides a structured path forward:

1. Identify the patent type. Determine whether you are dealing with a Romanian national patent, a classical EP validated in Romania, or a European patent with unitary effect. This dictates your available forums.
2. Conduct a freedom-to-operate and prior-art sweep. Commission a professional prior-art search covering patent and non-patent literature globally. This is the single most important investment in any challenge.
3. Choose the forum and assess the opt-out position. Check the UPC opt-out register. Decide whether OSIM, the Romanian courts, EPO opposition or UPC central revocation best serves your strategic objectives, or whether a combination is warranted.
4. Prepare evidence and appoint experts. Assemble prior-art packages, technical comparison tables and expert reports. If pursuing judicial nullity in Romania, anticipate the appointment of a court expert and prepare accordingly.
5. Seek interim relief if urgency demands it. If you are facing an infringement claim, consider applying for suspension of enforcement or opposing the patent holder’s injunction application, raising invalidity as a defence.
6. Coordinate multi-jurisdictional strategy. If the patent is validated in multiple states, align your Romanian proceedings with actions in other jurisdictions. The UPC central revocation route may offer the most efficient path, but national proceedings remain a valuable fallback. Connect with qualified patent litigation counsel in Romania to execute a coordinated strategy.

Sources

1. Unified Patent Court, FAQ / Jurisdiction of the UPC
2. Reddie & Grose, Romania Joins the UPC
3. OSIM, Romanian State Office for Inventions and Trademarks
4. European Patent Office, Opposition and Post-Grant Proceedings
5. WIPO, Opposition Systems Overview
6. Taylor Wessing, Nullity Proceedings in the UPC System
7. Bardehle Pagenberg, Unitary Patent & UPC Impact
8. Stoica & Asociatii, Romania Patent Litigation Country Guide (Legal 500)
9. Pinsent Masons, UPC Jurisdiction Despite Parallel National Proceedings