Is there a system of post-grant opposition proceedings? If so, how does this system interact with the patent litigation system?

Patent Litigation

Australia Small Flag Australia

Australia has a pre-grant patent opposition system for standard patents, but no post-grant opposition. As such the question of interaction with patent litigation does not arise.

Innovation patents are granted without substantive examination, and can only be opposed after grant and subsequent certification. If infringement proceedings are commenced by the patentee, any opposition will be stayed before the Patent Office.

The Patents Office may also commence re-examination of a granted patent. If Court proceedings are ongoing in respect of a patent, the Patents Office cannot revoke a patent following re-examination (or allow any amendment of the patent).

Austria Small Flag Austria

Against patents granted by the APO, anyone can file an opposition within four months from the announcement of the grant of a patent. It may be based on the same grounds as an invalidation action (see Question 8).

After a copy of the opposition is served, the patentee has two months to respond in writing. This time limit may be extended on reasonable grounds
The referee in charge of the respective case then decides on the further course of proceedings in respect of any further correspondence, hearing of the parties, obtaining evidence offered by the parties and the taking of evidence. The chairperson may order a public hearing on request or ex officio.

As described above under Question 2., the infringement court has to stay main proceedings if it considers the patent likely to be invalid. Pending opposition proceedings may be seen by the court as an indication of invalidity, but non-final decisions do not bind the court in any way. If the court stays the infringement proceedings the defendant has to file an invalidity action or opposition. If invalidity or opposition proceedings are already pending between different parties, the defendant may also join these proceedings. The court has to continue the infringement proceedings only after there is a final decision in invalidity proceedings.

Brazil Small Flag Brazil

The Patent Statute regulates post-grant review proceedings: any third party with legitimate interest or the BRPTO can challenge a patent within six months from grant. If the challenge is succeeded, the patent is invalidated with retroactive effect to the date of filling.

The patent litigation system is completely independent of the administrative procedure and the parties can always consider an invalidity lawsuit or a declaratory validity lawsuit. Brazilian federal courts will hear such cases even when post-grant review proceedings are pending before the BRPTO, and the possibility of obtaining preliminary injunctive relief staying the post-grant review proceedings makes this strategy particularly useful, especially concerning sensitive technology.

Canada Small Flag Canada

Canada does not have a system of post-grant opposition proceedings. If a party wants to challenge the validity of a patent, they need to commence a patent impeachment action before the Federal Court or commence re-examination proceedings before the Patent Office (see Question 10).

China Small Flag China

In China, there is invalidity proceedings, but no post-grant opposition proceedings.

Czech Republic Small Flag Czech Republic

A granted patent can be revoked at the IPO only. Any person can apply to cancel a patent. This application can be made even after the patent’s expiry if legal reasons for this exist.

Where the plaintiff agrees the courts will stay the pending patent cancellation proceedings.

France Small Flag France

Currently, there is no system of post-grant opposition proceedings against French Patent, but the Loi of 22 May 2019 provides for opposition proceedings but their conditions have not been determined yet. In case of an opposition before the European Patent Office, a stay is optional when the action is based on a European patent designating France.

Germany Small Flag Germany

Post grant opposition proceedings before the EPO or German Patent & Trademark Office can be initiated within nine months after grant of patent. During the opposition period and – if initiated – the opposition proceedings, invalidity actions before the Federal Patent Court are inadmissible.

In principle, German infringement courts can stay any infringement action pending the outcome of parallel opposition proceedings against the patent in suit. However, the defendant in the infringement proceedings has to demonstrate to the infringement court that it is highly likely that the patent will be invalidated. This threshold is rather high and infringement proceedings are thus only stayed in exceptional cases (about 10%), e.g. if new novelty destroying prior art is presented.

The decision whether the infringement proceedings shall be stayed or not is at the full discretion of the infringement court. The court generally considers no other factors than likelihood of invalidity.

Greece Small Flag Greece

Opposition proceedings before the Greek Patent Office are not provided for by the law. A patent can only be challenged before the competent civil courts.

India Small Flag India

Under Section 25 (2) of the Patents Act, 1970 at any time after the grant of Patent but before the expiry of a period of one year from the date of publication of grant of Patent, any person interested may give notice of opposition to the Controller in the prescribed manner on the grounds enumerated under the Section. A ‘person interested’ must be a person who has a direct, present and tangible commercial interest or public interest which is injured or affected by the continuance of the patent on the register.

There have been instances where a patent which is the subject matter of a patent litigation was revoked on a post grant against which an appeal was instituted. In such a situation, the Courts usually stay the proceedings until final adjudication regarding the grant of the patent.

Ireland Small Flag Ireland

Any person can bring an application to the High Court or the Controller for the revocation of a patent (Section 57, Patents Act).

If there are already court proceedings pending in Ireland in relation to a patent, it is not open to a party to take revocation proceedings before the Controller without leave of the High Court. However, where validity proceedings are already in existence before the Controller then the Court has discretion to stay infringement proceedings pending the Controller’s decision.
It is open to either party to apply to the Irish court for a stay of the Irish proceedings in circumstances where a corresponding European Patent is the subject of opposition proceedings before the EPO. The applicant for a stay argues that pressing on with the Irish proceedings runs the risk of conflicting decisions and /or wasted costs. In 2018 the Commercial Court allowed a partial stay of patent revocation proceedings between Eli Lilly and Eisai pending the determination of EPO opposition proceedings.

Israel Small Flag Israel

In formulating their decisions, Israeli courts and the Israeli Patent Office refer to and analyze foreign case law (in particular UK and US case law as well as case law from other common law jurisdictions and decisions of the European Patent Office) and are attentive to the legal situation and to recent judicial developments in other jurisdictions. Foreign decisions on issues for which no precedent in Israeli law exists may be of particular influence, inasmuch as the principles underling them are recognized under Israeli law and subject to the wide discretion of the Israeli tribunals. Similarly, foreign decisions in respect of foreign equivalents of a patent in suit may also be influential but of course are not binding and frequently the local courts or the PTO reach an outcome which is different form that obtained in the EPO or in courts of other jurisdictions.

Italy Small Flag Italy

The Italian patent system does not contemplate opposition proceedings, nor post-grant procedures of any other sort.

That being stated, with Italy being part to the European Patent Convention our system is obviously affected by the post-grant opposition system of the European Patent Office.
There is a reasonable degree of interaction between EPO opposition proceedings and our court proceedings. This is particularly true for PI proceedings. A patent that has “survived” the review of the Opposition Division or the Boards of Appeal is generally perceived as a strong patent and, thus, more likely to meet the prima facie case of validity which is required for the grant of preliminary relief.

We have no rules making it mandatory for judges to stay proceedings in view of pending EPO opposition procedures. Judges nevertheless have a discretionary power to stay ordinary proceedings if the EPO opposition procedure carries sufficient uncertainty that the patent will still exist at the end of the opposition and/or sufficient uncertainty over the claim set that will actually survive the opposition and the related scope of protection.

The above discretionary power is exerted on a case-by-case basis. Our experience is that some courts are more inclined to grant a stay, whereas other courts are definitely more reluctant.

Japan Small Flag Japan

Yes. Any person may file an opposition to a granted patent with the Commissioner of the Japan Patent Office no later than six months after the publication date of the Gazette for such patent. In practice, this system proceeds separately and independently from the patent litigation system.

Norway Small Flag Norway

There is a system of post-grant opposition proceedings in Norway. Oppositions may be filed within nine months after the grant of the patent. Invalidation actions before the Courts can be filed once a patent is granted. It is possible to file both an opposition and initiate an invalidation action before the Courts simultaneously. It will then be for the NIPO and the Court to decide whether the handling of the opposition or the Court case should be stayed to await the decision from the other body. Normally the Court will not stay a Court case awaiting the outcome of an opposition.

Poland Small Flag Poland

An opposition against the national patent can be filed within 6 months from the publication of grant. Polish law does not distinguish between opposition proceedings and invalidity actions in terms of substantive prerequisites. There are however significant procedural differences: the opposition can be filed by anyone (no need to show the legitimate interest in invalidation the patent) and no new grounds of the opposition can be added after the lapse of the 6-month deadline to file such opposition.

There are no specific rules that would concern the interaction between the opposition and infringement matters (bifurcated system). Similarly as for invalidity cases, it is unclear whether the infringement proceedings should or may be stayed pending the opposition proceedings. The Supreme Court has voiced for the stay in cases of industrial design infringement but this view has not been accepted by all courts in patent matters due to completely different rules of the patent prosecution.

Portugal Small Flag Portugal

No. However, INPI’s decision to grant a patent may be subject to an appeal before the IP Court. Such appeal can be filed by the party that has submitted the opposition at the patent office against the patent application and/or anyone “directly and effectively affected” by INPI’s decision to grant the patent.

Russia Small Flag Russia

An invention can be protected in Russia either by a Russian national patent (issued by the Russian Patent Office) or Eurasian patent (issued by the Eurasian Patent Office). The post-grant opposition proceedings exist for Eurasian patents only. Such opposition can be filed directly to the Eurasian Patent Office within 6 months after the grant and publication of an Eurasian patent. While post-grant opposition is being considered, no national challenge of the validity of the opposed Eurasian patent is allowed to be considered. So if patent owner files a patent infringement suit based on an Eurasian patent being under post-grant proceedings - there is a possibility to ask the Court to suspend court proceedings until the resolution of these proceedings, since defendant does not have defense to file an invalidation action in Russia. The court may provide such stay and is likely to provide it. Meanwhile for a Russian patent there is no post grant opposition proceedings, but only possibility to file an invalidation action (although it is an administrative proceedings before the Russian Patent Office first). Previously the Russian courts did not have legal possibility to provide a stay in an infringement action, if defendant files an invalidation action, but the Plenum of the Supreme Court as of April 23, 2019 No 10 clearly stated, that consideration of an patent invalidation action before RU PTO is a ground for a stay in a patent infringement procedure.

Singapore Small Flag Singapore

Singapore’s system of post-grant opposition proceedings is known as the revocation of a patent at the IPOS Registry. This is to be differentiated from the revocation of a patent in the High Court, which will generally be brought by way of a Defence and Counterclaim (see answer to Question 1 above). Once patent infringement proceedings have commenced in the High Court, revocation proceedings can only be brought in the High Court and these proceedings will be heard together with the patent infringement suit.

In the event that post-grant opposition proceedings have commenced at the IPOS Registry prior to the revocation action in the patent infringement proceedings in the High Court, the parties can consider whether any of the proceedings ought to be stayed, and if so, which one. While there are no provisions in the Rules of Court that provide for an automatic stay of proceedings, it is likely that parties will opt for the IPOS Registry proceedings to be stayed given that any appeal from the IPOS Registry would eventually be heard in the High Court.

The IPDR Bill, which has yet to come into force, will introduce a re-examination system as an alternative to revocation proceedings. This will allow third parties to request the IPOS Registry to re-examine a granted patent in certain situations, instead of having to engage in the relatively lengthy and costly process of revocation.

South Korea Small Flag South Korea

As a post-grant opposition procedure, the KPA provides patent cancellation procedure. The patent cancellation procedure is ex parte (no involvement by petitioner after filing a petition) and must be filed within 6 months from patent publication. The cancellation claim must be based on: (i) lack of novelty and/or inventive step based on at least one prior art publication(s) not cited by the KIPO examiner; (ii) lack of industrial utility; or (iii) violation of the first-to-file rule.

Cancellation proceedings, given their general timeline, do not proceed in parallel with infringement actions covering the same patents. Courts generally exercise their discretion to wait for the decision in the cancellation proceeding.

Sweden Small Flag Sweden

Yes, within nine months from the date the grant of a patent was published in the Swedish Patent Gazette, anyone can oppose the patent claiming that the basic requirements are not met for granting the patent (novelty, inventive step, enablement, added matter etc.). Patents for Sweden granted by the EPO are open for opposition based on the rules of the EPC.

Opposition proceedings before the Patent Office can occur concurrently with validity proceedings before court. The Swedish courts are reluctant to stay patent proceedings pending opposition (national or at the EPO). In practice, the court appears to stay the proceedings only if both parties agree to a stay.

Switzerland Small Flag Switzerland

In Switzerland, there is a system of post-grant opposition. The decision to uphold a patent in opposition proceedings is not binding on the FPC. Accordingly, the FPC may nonetheless declare such patent invalid.

Even if opposition proceedings are still possible or pending, a party may bring an action related to the respective patent (e.g., an infringement or an invalidity action). The FPC may, however, suspend the proceedings or defer judgment.

Taiwan Small Flag Taiwan

Anyone who would like to challenge the validity of a granted patent could file with TIPO an invalidation action against said patent. Examiners of TIPO will consider arguments by the party initiating this invalidation action and also argument made by the patentee responding the party filling the invalidation action. The examiners will render a ruling upon the invalidation action. Any party who disagree with the TIPO’s ruling could file an appeal with the appeal review board of the TIPO’s supervising agency. Any party who disagree with the ruling made by the appeal review board could bring an administrative lawsuit before the IP Court to seek proper remedies.

Meanwhile, defendants in patent infringement litigation usually raise an invalidity defense. Under Taiwan’s IP practice, the IP Court in a patent infringement proceeding shall determine the validity issue on its own and shall not stay the proceeding and wait for the TIPO’s ruling on the invalidation action. The IP Court’s decision upon the validity issue merely binds the parties of the patent infringement litigation and has no effects on anyone other than the parties of the patent infringement litigation. In a situation where the IP Court holds a patent is invalid, the IP Court will dismiss the patentee’s infringement lawsuit on the ground that the patentee is not able to enforce said patent. In this situation, as long as the TIPO is not a party to this proceeding, the TIPO will have to rule on the invalidation action independently; in other words, the IP Court’s invilidty decision in a patent infringement proceeding does not bind the TIPO. In practice, however, the TIPO will render its ruling upon an invalidation proceeding after the IP Court renders its decision in a patent infringement proceeding and will follow the IP Court’s opinion in respect of the validity issue. As such, the IP Court’s decision on the validity issue has a de facto binding effect upon the TIPO.

Thailand Small Flag Thailand

As of 2019, there is no post-grant opposition proceedings. However, note that the Patent Act may be amended in the near future.

Turkey Small Flag Turkey

The IP Law introduces a post-grant opposition system, whereby third parties can oppose a patent within six months of publishing the decision stating that the patent is granted.

The grounds for such a patent opposition are:

- The patent does not meet the patentability criteria.
- The invention is not disclosed in a sufficient manner.
- The patent exceeds the scope of the initial application.

Upon TPTO notifying the patent owner about an opposition, the patent owner can file a response or amendments to the patent within 3 months as of the date of the TPTO’s notification.

If the Re-examination and Evaluation Board examines the opposition and finds that the patent conforms with the IP Law, it will refuse the opposition. If the Board concludes that the patent partially conforms to the law, it will confirm the partial validity. It will inform the patent owner accordingly, requesting the amendment of the patent in line with partial approval. If no amendments are filed (or the amendments are not approved), the patent will be invalidated.

The post opposition grant system is highly associated with infringement claims, as by law, infringement claims cannot be settled until the post grant opposition proceedings are finalized.

United Kingdom Small Flag United Kingdom


In the UK, although it is possible to seek revocation of a European or nationally granted patent in the UK IPO and the national courts (the Patents Court and the IPEC) there is no national system of post‑grant opposition proceedings. 


Under Article 99 EPC, any person may give notice to the EPO of opposition to a patent within nine months of the publication of the mention of the grant of a European patent in the European Patent Bulletin. Under subsection (2), that opposition shall apply to the European patent in all the Contracting States in which that patent has effect. 

Article 100 EPC specifies that the only grounds upon which an opposition may be filed are: that the subject-matter of the patent is not patentable under articles 52 to 57, that the European patent 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, or that the the subject-matter of the European patent extends beyond the content of the application as filed, or if the patent was granted on a divisional application or on a new application filed under Article 61, beyond the content of the earlier application as filed.

Under Article 101 EPC, if the opposition is admissible, then the Opposition Division of the EPO will examine whether at least one ground under Article 100 prejudices the maintenance of the European patent, and if so, will revoke the patent, and otherwise, will reject the opposition. Under Article 101(3) EPC, the Opposition Division may decide to maintain the patent in amended form. Under Article 21 EPC, appeals from decisions of the Opposition Divisions may be heard by the Boards of Appeal.

Interaction of EPO Oppositions with UK patent litigation

Under Article 68 EPC, where a European patent has been revoked or limited in opposition, limitation or revocation proceedings, the patent shall be deemed not to have had effect from the outset, (to the extent that it has been so revoked or limited). Accordingly, if a European patent is revoked or amended in the course of post‑grant opposition proceedings, that European patent will be revoked and/or amended in any designated state, including for the purpose of any UK litigation proceedings. Given the potential for EPO post-grant opposition proceedings to impact national proceedings by revoking or limiting the claims of the patent-in-suit, a party to national proceedings may apply for a stay of those national proceedings pending the outcome of EPO proceedings. The decision to grant a stay will depend on a number of factors, including: the expected date of disposition of the EPO proceedings as against the UK proceedings, the prejudice faced by either of the parties to the national proceedings as a result of the grant of a stay, and the potential for wasted costs and time. Whether a UK court grants a stay will depend on all of the circumstances, and it should not be assumed that a UK court will necessarily grant a stay as a matter of course.

United States Small Flag United States

There are two main types of post-grant challenges. First, parties may seek review in adversarial proceedings at the PTAB. These proceedings include IPR, post-grant review (“PGR”), covered business method (“CBM”) review, and derivations. Second, parties may file ex parte re-examination requests, which are not adversarial and essentially place the challenged patent back in examination at the USPTO.

Accused infringers often try to stay litigation proceedings pending the outcome of a post-grant validity challenge. Courts are reluctant to grant stays unless and until the PTAB or re-examination branch of the USPTO decides to institute a review proceeding. Courts also look at other factors such as how soon the litigation will reach a trial, potential prejudice to the patent owner, and the accused infringer’s diligence in seeking the post-grant challenge.

Vietnam Small Flag Vietnam

Opposition proceedings are not available after the patent grant. If the defendant wants to challenge the patent, it must instigate invalidation proceedings (often before the patent office).

In administrative action, while invalidation proceedings are ongoing, administrative bodies must decline to take infringement cases. If the invalidation is filed in the middle of the infringement proceedings, the administrative bodies might either proceed with the final ruling or drop the case. In practice, MOST often holds off on infringement cases pending the final results of the invalidation action.

In civil action (before court), generally, the court is not obliged to stay the infringement proceedings pending the invalidation action. However, some courts have decided to hold off on the main proceedings to wait for the results of the invalidation proceedings.

Updated: November 14, 2019