Can a patentee seek to amend a patent that is in the midst of patent litigation?

Patent Litigation

Australia Small Flag Australia

The Court may amend a patent in patent proceedings. The Patents Office cannot amend a patent while relevant litigation is ongoing. Amendments in the Court must meet the usual requirements, namely the amendments must not disclose or claim additional matter beyond that disclosed in the complete specification as filed, the amended claims must in substance fall within the scope of the claims before amendment, and the specification must comply with the usual internal specification requirements.

Unlike in the Patents Office, the Court maintains a general discretion as to whether to allow amendments. To satisfy the Court that the amendments should be made (particularly where a granted patent is asserted against another party), the patentee will usually need to explain why the amendment was not sought earlier, including potentially waiving privilege in communications with patent attorneys. Amendments should generally be sought as early as possible in any litigation.

An application for amendment must be notified to the Commissioner for Patents and advertised in the Official Journal, with an opportunity for a third party to oppose. Any other party in the litigation may also oppose the application for amendment.

Austria Small Flag Austria

The Austrian Patent Act does not provide for special amendment or limitation proceedings. However, the patentee may waive parts of his patent via an application before the APO (Sec 46 PA). The APO examines the admissibility of the waiver and especially if the scope of protection is not in any way broadened or extended beyond the original disclosure by the partial waiver.

In infringement proceedings, the patentee is allowed to amend a claim, irrespective of whether he already filed a formal waiver with the Patent Office. Case law has confirmed that a limitation is always possible, even during infringement proceedings, provided that it leads to a narrower scope.

Brazil Small Flag Brazil

Yes. The judge might establish the amendment of a patent during litigation.

Canada Small Flag Canada

Re-examination: Any person (patentee or third party) may request re-examination of a claim of a patent at any time by filing with the Commissioner prior art, identifying the relevance of the prior art and the manner of applying it to the claim to be re-examined, and by paying a prescribed fee. A re-examination process can result in the original patent claims being upheld, found to be invalid, or amended.

Third parties do not have a right to participate in the re-examination proceedings beyond the initial filing of the prior art. Further, if the re-examination board determines that the request does not raise any substantial new questions affecting the patentability of the claim, the requesting party has no right to review or appeal. For these reasons, expungement actions in the Federal Court are typically preferred over re-examination proceedings.

The Federal Court has held that it can stay re-examination proceedings pending ongoing infringement proceedings, but it is unclear whether the court would be willing to stay an infringement action pending the determination of a re-examination proceeding.

Disclaimer/Reissue: In appropriate circumstances, disclaimer or reissue of a patent may also be available to a patentee. A disclaimer may be brought at any time but should be sought without delay when the defect is determined. A reissue can be sought within four years of grant.

China Small Flag China

In the patent litigation, amendments to a patent are not allowed. However, in the invalidity proceedings before the CNIPA, the patentee can amend claims generally by limited means, this is, deletion of a claim, deletion of a solution defined in a claim, further limitation to a claim, and correction of obvious errors.

The other party in the invalidity proceedings can oppose the amendments, but the decision rests with the CNIPA. Once the amendments are accepted, the pre-amendment claims would be deemed to be non-existent.

Czech Republic Small Flag Czech Republic


It must be borne in mind, however, that validity and infringement are bifurcated. In practice therefore the plaintiff has no reason to limit its patent in the infringement proceedings, and the defendant would challenge the patent before the IPO. The amendments would then be made in these proceedings.

The plaintiff could in some circumstances concede that the patent is partially invalid, and the court would then examine only the limited scope of the patent for infringement.

The plaintiff can also apply to limit its own patent at the IPO, however, it would have to argue lack novelty, inventive step or another reason for the limitation to succeed.

Third parties cannot intervene in the IPO proceedings or the litigation.

France Small Flag France

The patent holder of a patent can, at any moment,:
- Withdraw its patent;
- Limit the scope of its patent by amending one or several claims; with an effect ab initio, by filing an application for limitation of:

  • the French patent or the French part of a European patent at the Institut National de la Propriété Industrielle ; or
  • the European patent at the EPO (central limitation)

Germany Small Flag Germany

Claim amendments during infringement proceedings are admissible and commonly used in order to overcome validity issues of the claims as granted.

Rather than formally restricting the patent at the Patent Office, a claimant usually simply limits his asserted patent claim during the infringement proceedings, e.g. by combining a main claim with dependent claims. It is then up to the claimant to convince the infringement court that the limitation is admissible and overcomes potential invalidity objections. Since the infringement court cannot finally decide on the validity of such an amended claim, there is a high likelihood that the infringement court will stay the infringement proceedings pending the outcome of parallel invalidity proceedings, unless the claim amendment is clearly admissible, and the amended claim is clearly valid.

During invalidity proceedings it is standard procedure to limit the claims in view of relevant prior art. Validity of the limited claims must be shown to the Federal Patent Court. Here, particularly formal issues such as inadmissible broadening and lack of disclosure are usually relevant. Also, the patentee is free to limit the claim in limitation proceedings before the Patent Office.

Greece Small Flag Greece

There is no legal provision allowing for the amendment of a patent in the midst of patent litigation. As a rule, under the Greek law no post-grant amendment of a patent is possible. Only within the frame of a nullification proceeding, where the nullification action is directed against a part of a patent, the patent can be restricted to that extent.

India Small Flag India

Yes. An amendment of patent may be done in the following manner:

a) Before the Controller

As per Section 57 of the Patents Act, 1970, subject to the provisions of section 59, the Controller may, upon application made under this section in the prescribed manner by an applicant for a patent or by a patentee, allow the application for the patent or the complete specification [or any document related thereto] to be amended subject to such conditions, if any, as the Controller thinks fit: Provided that the Controller shall not pass any order allowing or refusing an application to amend an application for a patent or a specification [or any document related thereto] under this section while any suit before a court for the infringement of the patent or any proceeding before the High Court for the revocation of the patent is pending, whether the suit or proceeding commenced before or after the filing of the application to amend.

The application shall state the nature of the proposed amendment, and shall give full particulars of the reasons for which the application is made. Such application may be published and any person interested may, within the prescribed period after the publication thereof, give notice to the Controller of opposition thereto; and where such a notice is given within the period aforesaid, the Controller shall notify the person by whom the application under this section is made and shall give to that person and to the opponent an opportunity to be heard before he decides the case.

b) Before the Appellate Board or the High Court

Under Section 58 of the Patents Act, 1970 in any proceeding before the Appellate Board or the High Court for the revocation of a patent, the appellate board or the High Court may allow the patentee to amend his complete specification in such manner and subject to such terms as to costs, advertisement or otherwise as the appellate board or the High Court may deem fit. If in any proceeding for revocation, the Appellate Board or the High Court decides that the patent is invalid, it may allow the specification to be amended instead of revoking the patent. Where an application for such order is made to the Appellate Board or the High Court, the applicant may give notice of the application to the Controller, and the Controller will be entitled to appear and be heard and shall appear, if so directed by the Appellate Board or the High Court. Copies of all orders of the Appellate Board or the High Court allowing the patentee to amend the specification must be transmitted by the Appellate Board or the High Court to the Controller who will enter the same in the register.

c) Scope of amendments before the Controller, the Appellate Board and the High Court

Under Section 59(1) of the Patents Act, 1970 no amendment of an application for a patent or a complete specification or any document related thereto shall be made except by way of disclaimer, correction or explanation, and no amendment thereof shall be allowed, except for the purpose of incorporation of actual fact, and no amendment of a complete specification shall be allowed, the effect of which would be that the specification as amended would claim or describe matter not in substance disclosed or shown in the specification before the amendment, or that any claim of the specification as amended would not fall wholly within the scope of a claim of the specification before the amendment.

Ireland Small Flag Ireland

Section 38(2) of the Patents Act provides that the Court or the Controller, as the case may be, may, in the course of invalidity proceedings, allow the patent proprietor to amend the specification of the patent in such a manner as the Court or the Controller thinks fit and subject to such terms as to advertising the proposed amendment and as to costs. Any such amendment is deemed to have had effect from the date of grant of the patent.

Israel Small Flag Israel

It is possible to petition the Patent Office to grant patent term extension for patents covering pharmaceutical compounds, processes for their preparation, use thereof, pharmaceutical compositions containing them, processes for preparing such compositions or formulations, and medical devices.

A petition for patent term extension can be submitted no later than ninety days from the date of regulatory approval of the pharmaceutical preparation (non-extendable).

Patent term extension is only available with respect to the first regulatory approval permitting use of the active ingredient in Israel. It is not possible to obtain patent term extension if there were previous regulatory approvals for salts, esters, hydrates or different crystalline forms of the active ingredient. In accordance with Patent Office decisions, patent term extensions will not be available for a new combination of two previously registered active ingredients or a new single enantiomer of a previously registered racemic mixture.

If the pharmaceutical preparation is registered in the US, patent term extension will only be available if a US patent covering the pharmaceutical preparation was also extended in the US. Moreover, if the pharmaceutical preparation is registered in the EU-5 countries (Italy, Britain, Germany, Spain and France), patent term extension will only be available if a patent covering the pharmaceutical preparation was extended in at least one of the EU-5 countries.

The period of Patent Term Extension will be equal to the shortest period of extension granted to a patent covering the pharmaceutical preparation in the US or in any of the EU-5 countries. However, in any event, the period of extension will not exceed five years, and the overall period of the patent and the extension must end no later than fourteen years from the earliest date in which a regulatory approval was obtained in the US or in any of the EU-5 countries. Moreover, the period of extension will automatically expire when an extension granted to a patent covering the pharmaceutical preparation in the US or in any of the EU-5 countries is revoked or withdrawn.

Patent term extensions may be challenged similarly to basic patents. In recent years, most of the inter partes litigation in this area has revolved around the proper scope of the first regulatory approval principle.

Italy Small Flag Italy

A patent in the midst of litigation can be amended either by means of an application to amend filed directly at the Italian Patent and Trademarks Office (PTO) or, if the litigation includes a claim of invalidity/revocation, directly in court.

Our system does not contemplate the filing of auxiliary requests. No matter whether it is filed before the PTO or in court, an application to amend is a one-off withdrawal of the broader scope of protection defined by the previous claim set.

Japan Small Flag Japan

Yes. The patentee is, in principle, eligible to file a trial for correction in order to correct the patent even while a patent lawsuit is pending. In a trial-for-correction process, no third party is permitted to file an opposition, etc. against a correction. As an exception, while an invalidation trial or a lawsuit for trial-decision cancellation is pending for the relevant patent, the patentee is ineligible to file a trial for correction; however, the patentee is permitted to file a demand for correction in order to correct the patent within a predetermined period during the invalidation trial proceedings. When filing a demand for correction, the demandant of the invalidation trial is allowed to file an opposition as to whether the correction is acceptable. In order for such correction to be accepted, it must satisfy, for example, the following requirements: the correction does not correspond to an addition of new matter; and the correction does not fall under a substantial change or expansion of the claims. When a correction is accepted, the patent application, etc. is regarded to have been filed through the corrected specification and claims.

Norway Small Flag Norway

A patentee is entitled to seek to amend a patent during a litigation. This can be done at any stage of the litigation. The patentee can seek to amend the patent by filing auxiliary claims in the litigation or by filing a request for administrative limitation to the Norwegian Industrial Property Office (NIPO).

Poland Small Flag Poland

Post-grant patent amendment has not been regulated so far. In the revocation proceedings, amendment may be considered only in relation to a partial patent invalidation (i.e., if the Patent Office considers the patent to be valid in part). It is, however, even controversial to what extent a patent may be partially invalidated by the Patent Office.

Even if a possibility to partially invalidate the patent is considered and the patent holder files proposals for amendment of patent claims, they are not binding for the Patent Office.

In practice, so far both the Patent Office and administrative courts have been very reluctant to allow partial invalidation and have limited it to maintaining the patent with regard to one or more categories of claims but disallowed any amendment to the patent claims per se.

Portugal Small Flag Portugal

Patents can be amended, provided that such amendments do not affect the elements of the patent that are essential and characteristic thereof. An amendment application cannot be opposed but any third party who might be “directly and effectively affected” by INPI’s decision may appeal the decision.

Patents may be limited (the amended claims shall not extend the protection of the patent as granted) either via the administrative route before INPI (a) or the judicial route before the IP Court (b):

a) The IPC does not expressly provide for the requirements that need to be examined. INPI will assess and decide on whether the amended claims reduce the scope of protection of the patent as granted, whether the amended claims are clear, supported by the description and do not add matter beyond the application as filed. A decision by INPI takes approximately 2-5 months. If the limitation is granted, INPI publishes a notice of the alteration of the claims. The IPC does not provide for a deadline for third parties to oppose the limitation application but any third party who might be “directly and effectively affected” by INPI’s decision may appeal the decision within 2 months of the respective publication (or the date of the respective certificate requested by the appellant, if made earlier). If the amendment is not granted, INPI only communicates the decision to the applicant. The patentee may appeal this decision to the IP Court, within 2 months from the date of reception of the communication of the decision denying the limitation.

b) The patent holder is entitled to limit the claims before the IP Court. The limitation of the scope of protection of a patent claims in court proceedings is uncommon in Portugal.

Russia Small Flag Russia

Article 1399 of the RUCC permits amending the claim by withdrawing independent claim (and dependent claims thereof). The RUPTO registers such amendment and makes appropriate publication based on petition of the patent owner irrespective of any pending litigation.

Third parties can oppose such amendment with the IP Court within three months after the respective party became aware of such an amendment due to the general rule of law.

The patent owner has the right to amend the claims with an inclusion of dependent claim(s) into respective independent claim during the invalidation proceedings to overcome objections on novelty and/or inventive level. The case law specifies that while amending the claims there is no possibility to include features from the specification, but only from the dependent claims. Since such amendments are done during the invalidation procedure, only a party involved into such procedure can object against such amendment and oppose it with the IP Court afterwards.

Singapore Small Flag Singapore

A patent that is the subject of a patent litigation may be amended in the midst of patent litigation.

The patentee may only apply do so if the validity of the patent has been put in issue before the Court or the Registrar. This would usually be in a case where there is a counterclaim filed by the defendant and alleged infringer to invalidate and revoke the patent. A patentee intending to do so must give notice of his intention to the Registrar and a copy of an advertisement containing relevant details of the patent sought to be amended must be published in the patent journal by the patent Registry. Such details include the full particulars of the amendment sought, whether the amendment is by way of deletion or re-writing of claims and the patentee’s address for service within Singapore.

Any person may oppose the amendment and that person must give written notice of his intention to oppose to the patentee within 28 days after the publication of the advertisement. This notice is to be accompanied by a statement of opposition, which is to contain full particulars of all grounds of opposition to the patentee’s application to amend.

After the expiration of 42 days from the appearance of the advertisement, the patentee must make his application to amend by way of summons in the proceedings pending before the Court. A copy of the summons and a copy of the specification with amendments marked up in coloured ink must be served on the Registrar, the parties to the proceedings and any person who has given notice of his intention to oppose the amendment.

An amendment application will be refused if it is made in respect of a matter which has been disclosed in an earlier application or in the specification of a patent which has been granted, or if it discloses additional matter being matter that extends beyond that disclosed in an earlier application.

Further, the Court retains the discretion to allow an amendment. The following factors are relevant to the exercise of this discretion:

(a) whether the patentee had disclosed all relevant information with regard to the proposed amendments;

(b) whether the amendments comply with the statutory requirements;

(c) whether the amendments introduce additional matter;

(d) whether the amendments extend the scope of protection of the patent (i.e. the amended patent is broader than the patent in its current form);

(e) Whether there had been undue and inexplicable delay on the patentee’s part in taking out the amendment application;

(f) whether the patentee had sought to obtain an unfair advantage from the patent by delaying the amendments which it knew were needed; and

(g) whether the patentee’s conduct discourages the amendment of the patent.

Following a successful application to amend the patent specifications, the patentee (i.e. the plaintiff) may be in a better position to resist any claims from the defendant that the patent in the suit is invalid on the ground of anticipation by the prior art. This is generally why a patentee seeks to amend its patent.

However, the adverse implication to an application to amend a patent specification is that it indicates to the adverse party and to the Court that the unamended patent as granted may not be valid. As such, if the application to amend is rejected, it is more likely that the unamended patent would not withstand an invalidity/revocation attack from the adverse party.

The Court has the discretion to direct whether the hearing of the patent amendment application should be at the trial of the patent infringement suit or separately, which would be before the trial of the patent infringement suit. While the patent amendment application is considered an interlocutory application where cross-examination of deponents is typically not allowed, given the complexity and the finding of facts involved in a patent amendment application, expert witnesses are usually cross-examined at the hearing of a patent amendment application that is separate from the trial of the suit.

South Korea Small Flag South Korea

Yes, there are two ways the patentee can seek to amend a patent during pendency of patent litigation: filing a correction trial and filing a request for correction. The patentee may bring a correction trial before the IPTAB to amend the claims and/or specification of the patent after issuance. In case a trial for correction is filed while an infringement action involving the patent is pending, the court reviewing the infringement action may at its discretion stay the infringement action until a decision in the trial for correction is rendered. A third party may file opinion and evidence as to the validity of the amendment, but it cannot participate in the proceeding as a party. An interested party, however, may file a trial for invalidation of correction to challenge the grant of the amendment any time after the amendment is effectuated via a correction trial.

A correction trial cannot be brought if an invalidation action is in progress before the IPTAB. Instead, a request for correction may be filed to amend the patent as part of, and under the schedule set within, the invalidation proceeding. Once the amendment is effectuated, it can be challenged via a trial for invalidation of correction.

Amendment by way of a correction trial or request for correction may be made only for the purpose of (i) narrowing the scope of the claims; (ii) correcting obvious errors; or (iii) clarifying ambiguous languages. Further, corrections can only be made within the disclosure made in the specification and the drawings and cannot widen or substantially change the scope of the claims. If the amendment is effectuated, the patent is deemed to have been filed, published and allowed in the amended form.

Sweden Small Flag Sweden

A patent can be amended by the Swedish Patent Office unless opposition or invalidity proceedings are pending against that patent. The courts have the power to amend claims, if this is requested in invalidity proceedings.

Switzerland Small Flag Switzerland

It is possible for a patent owner to amend the patent claims during patent litigation (either by request with the office or before the court). The claims may be amended by deleting claims altogether, by combining an independent claim with one or more dependent claims, or by limiting a claim in some other way. The restricted claims must relate to the same invention and define an embodiment that was included in the specification of the published patent and the application.

Taiwan Small Flag Taiwan

Under Taiwan’s patent practice, a patentee is allowed to amend a patent that is in the midst of patent litigation. In practice, a patentee can seek to amend a patent whenever necessary without the limitation of time, as long as the patent is valid and has not yet conclusively revoked. However, a patentee who would like to amend a granted patent can only delete claims, narrow the scope of claims, correct errors or translation errors, or clarify ambiguous statements. Except for the correction of translation errors, an amendment cannot go beyond the scope of content disclosed in the description, claims, or drawings as filed, or substantially enlarge or alter the scope of the claims as published. Examiners of TIPO will examine the amendment and determine whether the amendment is allowable. At the same time, in a patent infringement litigation, if a patentee amends the patented claims which were used by the patentee to assert the infringement, the IP Court will consider whether the amendment is allowable in the situation where the defendants disputes the amendment.

Thailand Small Flag Thailand

A patent cannot be amended after grant, except for cancellation of the patent or patent claim(s). If an invalidation action has already been filed against the patent, cancellation of patent claims is also prohibited.

Turkey Small Flag Turkey

The legislation does not allow the patent owners to amend their patents during patent litigation. Amendment is only allowed under the following articles:

According to Article 99/4 of the IP Law, the patent holder is entitled to amend his/her patent after the publication of the patent grant decision in the Official Gazette as a response to post-grant opposition. These amendments are examined by the TPTO, and if they are approved, the patent is published in the Official Gazette. No further opposition procedures against the amendment is available. If TPTO, has the opinion that the patent or the changed version complies with IP Law, it shall decide for the patent or the changed version, if any, to maintain the position.

Likewise, in line with the Article 103/1 of the IP Law, the patent holder is entitled to amend his/her patent application during the prosecution proceedings before the TPTO, including the opposition periods, in a manner that the first scope of the application is not exceeded.
Moreover, Turkey became a party to the European Patent Convention (“EPC”) on 29 January 2000, and once this agreement is duly approved by the Grand National Assembly of Turkey and published in the Official Gazette, any provision of the EPC has the power of national law by constitution.

According to Article 138/3 of the EPC, in proceedings before the competent court or authority relating to the validity of the European patent, the proprietor of the patent shall have the right to limit the patent by amending the claims. However, the practice of this article and the precedents whereby such requests accepted are very few.

United Kingdom Small Flag United Kingdom

A patentee can seek to amend a patent that is in the midst of patent litigation either nationally (through UK courts) or centrally (through the European Patent Office “EPO”).


In proceedings before the court or the Comptroller in which the validity of a patent may be put in issue, an application to amend a patent must be made pursuant to the specialised procedure under Section 75 Patents Act. This provision empowers the court or the Comptroller to allow the patentee to amend the specification of that patent in such a manner, and subject to such terms as to advertising the proposed amendment and as to costs, expenses or otherwise, as the court or Comptroller thinks fit.
A person may give notice to the court or the Comptroller of his or her opposition to a patentee’s proposed amendment, in which case the court or the Comptroller shall notify the patentee and consider the opposition in deciding whether the amendment or any amendment should be allowed.

Section 76 Patents Act importantly specifies that an amendment of the specification of a patent is not allowable if it would result in the specification disclosing additional matter, or the extension of the protection conferred by the patent.

Once an amendment is allowed, it is deemed to have retrospective effect from the date of grant. Where there is a finding of patent infringement in respect of a patent which is subsequently amended (e.g. in the EPO), the patentee can no longer rely on that earlier finding of infringement to claim damages, because there has not been a finding of infringement of the patent in its amended form.

An application to amend a patent can either take place on a conditional basis, whereby the patentee maintains the patent or relevant patent claim to be valid in its unamended form, or an unconditional amendment, whereby the patentee accepts that the unamended patent or patent claim is invalid.

A national amendment of a patent specification has typically not been allowed in past cases following an unsuccessful defence to a challenge to the validity of the patent.


Pursuant to Article 105a of the EPC, the proprietor of a European patent may in certain circumstances file a request with the EPO to limit it by amendment of its claims. The effect of such a central limitation is that all national designations of the patent will be amended ab initio, including any such UK designation.

The EPC sets out certain requirements for amendments. These are contained in Article 123(2) EPC (no added matter) and Article 123(3) EPC (no claim broadening in any amendment after grant). Any amended claim must also satisfy the requirements of Article 84 (conciseness, clarity and support).

Where patent litigation proceedings are underway in the UK and a patentee subsequently files for a central amendment, the UK court may stay the UK proceedings while the central amendment application is considered, though it will not necessarily do so. The circumstances where a UK court may grant a stay are considered in further detail at Question 16 below.

United States Small Flag United States

A patent owner cannot amend a patent claim through a litigation proceeding. Nevertheless, a patent challenged at the PTAB may be amended during the PTAB proceeding. Because PTAB proceedings are adversarial, any proposed amendments may be challenged by the party that commenced the proceeding. Claim amendments at the PTAB may only narrow claims and may not broaden claims in any respect. When amendments are made, the patent owner may potentially forfeit past damages that may otherwise have been available for the original claims.

Vietnam Small Flag Vietnam

It is possible to amend a patent during infringement proceedings. However, this can only be carried out by the IP Office and not the court or the administrative bodies. The court and the administrative bodies can stay proceedings pending the conclusion of the amendment proceedings.

Updated: November 14, 2019