Once a patent is granted by the European Patent Office (EPO), it becomes a bundle of national patents. As a result when looking to amend a European patent after grant, despite attempts to harmonise national patent laws and practice, different countries may have different requirements as well as fees for making changes to the patent in those states.

The revision of the European Patent Convention (EPC) in December 2007 introduced Article 105a EPC and a relatively quick, cost effective and straightforward centralised procedure at the EPO to amend a European patent in all validated states after grant. In this respect the patentee may limit the scope of their European patent at any given time after grant, except when the patent is being opposed or appealed at the EPO.

The request requires payment of a fee (1165 EUR) and the proposed limiting amendment(s) should be clear (Article 84 EPC), not add matter (Article 123(2) EPC), and not extend the protection conferred (Article 123(3) EPC). Unlike reissue proceedings in the United States, the central limitation procedure does not re-open the prosecution of the patent and there is no assessment of novelty or inventive step of the amended claims.

Once the limitation request is allowed, the patentee will have to pay a fee for republication of the amended patent and file translations of the amended claims into the other official languages of the EPO.

It is not permissible to amend merely to resolve a clarity issue or to add additional claims directed to different subject-matter, there must be a reduction in scope. Non-limiting amendments are only allowed if they are a consequence of a limitation already present in the claim. Even though limiting the subject-matter of the dependent claims may be accepted, addition of new dependent claims is not allowed unless they are a direct consequence of the limiting amendment.

This procedure may be useful for example to address deficiencies in a patent claim especially when litigation is contemplated in a number of states. In a scenario where a patentee is made aware of a document that might prejudice the validity of their granted patent, they may proactively choose to amend the claims of their European patent by filing a request for limitation at the EPO. Usefully here, the patentee is not obliged to explain why they wish to limit the scope of their European Patent.

To summarise, post grant central limitation at the EPO is an efficient and cost effective way for a patentee to restrict the scope of their granted patent in a consistent manner in all validated states. For further information on the procedure and associated strategies, including coordinating with corresponding national and also US proceedings, please go to our webinar here on post grant amendment strategies.