Definition and Legal Nature of the Patent Nullity Action
Die Patent nullity action is a legal remedy in German patent law, by which the complete or partial revocation of a granted patent can be requested before a court. The purpose of the nullity action is to annul a patent retrospectively if it becomes apparent that it was wrongfully granted, in particular because the legal requirements for patentability were not met or have subsequently ceased to exist. It constitutes a central instrument for legal control of patent granting alongside opposition proceedings.
Distinction from Other Proceedings
The patent nullity action differs from the opposition procedure before the patent office, which is only possible for a certain period after patent grant. While the opposition is lodged directly against the patent and its grant at the German Patent and Trade Mark Office (DPMA), the nullity action is a judicial proceeding before an ordinary court that can be initiated after the opposition period has expired. The nullity action must also be distinguished from the action for cancellation against utility models.
Statutory Foundations
The principal legal basis for the nullity action against German patents is Section 81 Patent Act (PatG) (Patent Act), supplemented by further provisions of the Patent Act as well as international agreements such as the European Patent Convention (EPC) for European patents with effect in Germany.
Jurisdiction and Course of Proceedings
The authority responsible for the decision on a patent nullity action is the Federal Patent Court (BPatG) as the court of first instance. The appellate instance lies exclusively with the Federal Court of Justice (BGH). The proceedings take the form of adversarial civil litigation.
Judicial Jurisdiction
- Federal Patent Court (Section 81 (4) PatG): Court of first instance competent for nullity proceedings.
- Federal Court of Justice: Solely competent instance for appeals (so-called leap-frog appeals excluded).
Parties to the Proceedings
- Plaintiff: Any natural or legal person may bring a nullity action; a legal interest is not required.
- Defendant: The holder of the contested patent.
Admissibility of the Action
Legal Standing
A nullity action can in principle be brought by anyone (popular action principle). This means that being affected by the patent is not a prerequisite for standing to sue.
Defendant
The defendant is always the person entered as the patent proprietor in the patent register at the time the action is brought. Changes of proprietorship during the proceedings result in procedural succession (Section 265 ZPO analogously).
Deadlines
A patent nullity action can be filed throughout the entire term of the patent—i.e., up to 20 years from the filing date (Section 16 PatG). It may also be filed after a patent infringement action has been initiated.
Preclusion Provision
If opposition proceedings or a nullity action have already been unsuccessfully conducted for the patent, bringing a new nullity action is not excluded. However, identical subject matters of the application may be restricted through duties of cooperation and principles controlling abuse.
Grounds for Action (Grounds for Nullity)
Die Grounds for Nullity are exhaustively set out in Section 22 PatG. The most important grounds are:
1. Lack of Patentability
Novelty and Inventive Step
A patent can be revoked if its subject matter is not new or does not involve an inventive step (Sections 1 to 5 PatG).
Industrial Applicability
If industrial applicability is lacking, the patent is void (Section 5 PatG).
2. Insufficient Disclosure and Unallowable Extension
If the subject matter of the patent is not disclosed clearly and completely enough for a person skilled in the art to carry it out (Section 34 PatG), or if the scope of protection has been unallowably extended subsequently (Section 21 (2) PatG), there is a ground for nullity.
3. Non-patentable Inventions
Certain inventions are excluded from patentability (e.g., Section 2 PatG: discoveries, scientific theories, mathematical methods).
4. Unlawful Appropriation
If the patent was granted for an unlawfully appropriated invention, the entitled party (e.g., the true inventor) may apply for nullity.
5. Lack of Jurisdiction with respect to the Patent
Errors in the examination of jurisdiction, for example within the framework of the European Patent Convention, may constitute a ground for nullity.
Course of the Nullity Proceedings
Filing of the Statement of Claim
The statement of claim includes the application for complete or partial declaration of nullity of the patent, as well as the identification and substantiation of the asserted grounds for nullity.
Defense of the Patent Proprietor
The patent proprietor may oppose the application, present arguments in defense, and may also introduce limiting patent claims into the proceedings, if necessary.
Oral Hearing
As a rule, an oral hearing takes place, in which the court may hear expert witnesses if necessary.
Judgment and Legal Remedies
The Federal Patent Court pronounces the judgment by which the patent is declared (partially) null and void or legally valid. An appeal to the Federal Court of Justice is permissible against the judgment.
Effects of the Judgment
Retroactive Effect of Nullification
The declaration of nullity of a patent has ex tunceffect—that is, retroactively from the date of grant (cf. Section 22 (2) PatG). The patent is deemed never to have existed. Ongoing patent infringement proceedings may be affected by this.
Binding Effect
The nullity judgment has binding effect for civil courts (Section 148 ZPO). However, infringement proceedings that have already been concluded with res judicata remain unaffected.
European and International Aspects
European patent with effect in Germany
A nullity action may also be brought before the Federal Patent Court, by analogy, against a European patent validated in Germany (Section 81 (2) PatG in conjunction with Art. II Section 6 IntPatÜG). After exhaustion of proceedings at the European Patent Office, only national remedies are available.
Unitary Patent System
The Unitary Patent introduced in 2023 provides for its own nullity proceedings before the Unified Patent Court (UPC). The effect of its decisions extends to all participating Member States.
Distinction from Related Remedies
Opposition Proceedings
The opposition procedure (Sections 59 ff. PatG) is an ex officio investigation procedure at the DPMA, by which objections to the patent grant can be raised within nine months after grant.
Cancellation Procedure
The cancellation procedure exists in German utility model law and is functionally similar to the nullity action in patent law.
Costs and Disputed Value
The costs of the nullity proceedings are determined by the value in dispute, which is usually set by the court. They include court fees and the costs of legal representation for the parties. Generally, the proceedings are more expensive than opposition proceedings before the patent office.
Literature and Further References
- Patent Act (PatG), especially Sections 21, 22, 81 ff.
- IntPatÜG – Act on International Patent Agreements
- European Patent Convention (EPC)
- Unitary Patent and Agreement on a Unified Patent Court (UPC)
- Federal Patent Court, procedural information
Conclusion: The patent nullity action is a central instrument for quality assurance in the patent system. It ensures that only patents survive that withstand legal scrutiny. Through judicial review throughout the entire term, there is an effective corrective for controlling the validity of patent protection rights.
Frequently Asked Questions
Who is entitled to bring a patent nullity action?
In principle, a patent nullity action can be brought by anyone asserting a legal interest in the declaration of invalidity of a patent. According to Section 81 (1) PatG, the action is open to everyone, as the patent, as an exclusive right, can affect not only direct competitors but also other potentially affected parties. In particular, the general public and companies whose business activities are hindered by the patent may file a nullity action. It is not necessary for an infringement action to be pending against the plaintiff or for a warning letter to have been sent. For example, patent exploitation companies, associations, or individuals are also entitled to bring an action if they can demonstrate a legitimate interest worthy of protection.
Which courts have jurisdiction to decide on a patent nullity action?
Exclusive subject-matter jurisdiction for patent nullity actions against German patents and the German parts of European patents lies with the Federal Patent Court (BPatG) pursuant to Section 65 (1) PatG. The proceedings there are conducted before a nullity senate, which is composed of members with technical and legal expertise. There is no concurrent jurisdiction with civil courts; thus, patent nullity actions in Germany are not heard by regional courts but exclusively by the Federal Patent Court. In appellate proceedings, only the Federal Court of Justice (BGH) has jurisdiction as the appeal instance.
Which grounds for invalidity can be asserted in patent nullity proceedings?
The grounds for nullity that can be asserted in patent nullity proceedings are exhaustively regulated in Section 22 PatG. Main grounds include, in particular, lack of patentability (novelty, inventive step), insufficient disclosure, inadmissible extension of the subject matter of the patent beyond the content of the original application, unlawful removal, and lack of patentability of the subject matter for other reasons. The plaintiff must substantiate and prove which of the cited grounds render the contested grant of the patent incorrect. However, questions regarding infringement of the patent or disputes about licensing rights are not decisive.
How do the proceedings before the Federal Patent Court work?
The nullity proceedings begin with the filing of the action and the reasoning of the nullity grounds. Once a permissible action has been received, the patent proprietor is given an opportunity to respond. In the further course of the proceedings, there is usually a written exchange of arguments with briefs and evidence, such as prior art references. The court may hear expert witnesses and, after completion of the written phase, will schedule an oral hearing. There, the parties are heard and the scope of examination is discussed. After deliberation, the court decides by judgment on the validity or nullity—also partial—of the patent. The proceedings are characterised by particular technical complexity and often require extensive expert opinions to establish the relevant technical knowledge.
Is it possible to file a nullity action during pending infringement proceedings?
Yes, the nullity action is the central means of defense against the enforcement of a patent in infringement proceedings. Patent infringement disputes are adjudicated by civil courts; however, titles can only be enforced if the patent is also valid. To comply with the ‘principle of separation’ in German patent law, issues of patent validity are not clarified in the main infringement action, but exclusively in parallel nullity proceedings before the Federal Patent Court. It is common in infringement proceedings to request a stay of proceedings under Section 148 ZPO until a decision on the nullity action is reached. It is therefore advisable to file the action as early as possible to preserve the chance of a stay.
What legal remedies are available against the judgment in patent nullity proceedings?
Appeal against judgments of the Federal Patent Court in patent nullity proceedings is not available to the parties, as the procedural hierarchy is limited to two levels. Instead, revision (appeal on points of law) to the Federal Court of Justice is generally admissible under Sections 100, 110 PatG. Revision may be filed by either the unsuccessful party or the patent proprietor and is limited to questions of law; that is, the Federal Court of Justice does not re-examine all the facts but rules on the legal assessment and interpretation of patent law and the relevant technical issues within its competence for revision.
What costs may arise in the course of a patent nullity action?
Nullity proceedings are associated with significant costs. These include court fees at the Federal Patent Court, the amount of which depends on the value in dispute and regularly amounts to several thousand euros. In addition, there are costs for legal representation of the parties—usually by a patent attorney and a Rechtsanwalt in a joint practice—, which may also include costs for expert witnesses appointed by the parties or the court, as well as translations of technical documents. In case of failure, the plaintiff is generally obliged to pay the court costs and the necessary expenses of the opposing party. The allocation of costs is regulated in Sections 84 ff. PatG, with the court making an individual decision on costs in specific cases.
