It has now been over six months since the doors of the Unified Patent Court (UPC) opened, bringing numerous changes for European patent applicants and recent patentees. While these adjustments have already been the subject of focused discussion, parallel subtleties have recently emerged.

The EPO top-up search

European patent portfolio holders are well aware of the meaning behind receiving a communication under Rule 71(3) of the European Patent Convention (EPC) – also known as a communication of intention to grant a European Patent.

As an annex to this notification from the European Patent Office (EPO) comes the so-called “Form 2906” – sometimes overlooked despite its critical importance. It can reveal undetected national prior rights documents that could potentially invalidate the subsequently granted patent if essential measures are not taken in time. For this reason, the EPO has implemented a new search system, benefiting applicants from September 1, 2022. The EPO now automatically broadens the scope of the supplementary search conducted during the grant phase to highlight national patent applications and patents from EPO contracting states. This search, conducted at no cost to the applicant, aims to provide guidance regarding the possibility of the granted patent to benefit from unitary effect. The implications of validating said patent in certain countries could also be affected.

National prior rights as post-grant risks

So-called national prior rights are national patent applications from states participating in the EPC, having a priority date preceding that of the considered European Patent but published afterward.

Article 139(2) EPC currently governs the principle of national prior rights, stating that their effects are determined for each jurisdiction according to its own national legislative provisions.

Assuming that a relevant, i.e., novelty-destroying, national prior right is identified during the EPO top-up search, the validity of the corresponding national part of a granted European Patent may be negatively affected in case of a revocation action before a competent national court. This is despite the fact that national prior rights do not impact the grant of a European Patent by the EPO as they are not part of the state of the art according to Article 54(2) and (3) EPC, being published after the effective date of the subject matter of the considered European Patent. Hence, the existence of a national prior right does not prevent the grant of a European Patent.

However, if seeking to validate in the country corresponding to this national prior right, a patent holder should take appropriate measures. These may include:

• Filing reasoned amendments or corrections to the text in response to the intention to grant and Form 2906, as provided by Rule 71(6) EPC.
• Filing a further request for amendments after approving the text communicated by the Examining Division, as provided by Rule 137(3) EPC.
• Providing the EPO with a set of specific claims for the state where the national prior right has been filed in a procedure corresponding to post-grant limitation.

These options play a fundamental role because things prove to be equally challenging when a European Patent with unitary effect is sought.

Impact on the Unitary Patent route

Since June 1, 2023, the entry into force of the UPC Agreement (UPCA) has allowed applicants to request unitary effect following the grant of a patent. There are numerous strategic elements involved in this choice, such as costs and annuities, territories of interest and even the strength of the patent.

A widely recognized consequence of Article 65(2) UPCA is that a single national prior right identified in a participating state of the UPC could serve as a basis for the centralized revocation of a patent granted with unitary effect.

However, the mere existence of national prior rights does not preclude a request for unitary effect for a European Patent as such. For instance, a known exception arises when the relevant national prior right originates from an EPC contracting state that is not a participant in the UPC, such as the United Kingdom or Spain. In this particular case, a national prior right does not necessarily imply foregoing a request for unitary effect since the aforementioned legal basis does not apply.

Otherwise, i.e., should the national prior right come from a UPC participating state, there is a risk of partial or even total nullity being declared for all participating states of the UPC. Additionally, Article 3(1) of Regulation (EU) No 1257/2012 stipulates that: “A European patent granted with different sets of claims for different participating Member States shall not benefit from unitary effect.” Therefore, the extent to which the validity of a European Patent with unitary effect can be affected is particularly severe and should not be neglected.

To alleviate these risks, patentees may:

• Choose the unitary route while filing a limitation of the claims to the EPO for the entire unitary block, thereby limiting protection in all participating countries simultaneously, or
• Choose not to request unitary effect; instead, validating the European Patent nationally so that the claims would only have to be limited in the specific country of the national prior right.

Though sometimes overlooked, it is important to remember that the second option is not devoid of risks either.

Impact on validations in EPC member states

As discussed above, it is not possible to provide a different set of claims beforehand for the state in question if one wishes to have unitary effect. On the other hand, it is allowed to file different sets of claims for different states when validating the European Patent in any selection of the 39 EPC members.

In the event of an identified national prior right from an EPC contracting state, it is essential to examine it thoroughly before deciding to request unitary effect or initiating the necessary actions for validation. And even in cases where unitary effect is not desired, it remains crucial to check the content of all annexes of the notification of intention of grant to ensure that the rights of the European Patent persist smoothly throughout its lifespan.