Narrowing the claim by adding a manufacturing step can broaden protection: EPO Board of Appeal confirms Article 123(3) EPC limits (T 0847/24)

A recent EPO Board of Appeal decision (T 0847/24) confirms a risk we frequently encounter in the European patent practice: an amendment that appears to narrow a claim by adding a manufacturing step may nonetheless extend the scope of protection contrary to Article 123(3) EPC. This decision is particularly relevant in sectors such as medical devices and other digital design-to-manufacture fields, where inventions may span computer-implemented design steps and physical end products.

The central issue: method to product extension via Article 64(2) EPC

The patent at issue in the Board of Appeal decision concerned a computer-implemented method for configuring a physical object in the field of medical implants — essentially generating configuration data for a customised implant based on patient-specific or design parameters. In its granted form, the claim was directed to a method producing data representing the configured implant, rather than directly covering the physical implant itself.

During opposition proceedings, the patentee sought to reinforce the claim by adding an explicit step of manufacturing the configured implant. The apparent intention was to align the claim more closely with commercially relevant embodiments, namely the physical medical device implanted in a patient, and to strengthen enforceability against manufacturers of the final product.

However, this amendment triggered a fundamental legal issue.

The Board confirmed that under Article 64(2) EPC, a process claim confers protection not only on the process itself but also on the product directly obtained by that process. However, this principle only applies within the boundaries of what the granted claim actually defines as the “directly obtained” product.

In the present case, the granted claim did not define a manufacturing process or a process resulting in a physical implant — it was limited to a computational configuration method producing data. Accordingly, the physical implant was not a product directly obtained by the claimed process.

By introducing a manufacturing step, the patentee attempted to shift the claim from a purely data-generating method to a method that produces a physical medical device. This, as the Board concluded, effectively introduced a new category of protection.

The decisive finding: Article 123(3) EPC violation

A key passage of the decision is particularly significant:

“Article 123(3) EPC provides that a European patent may not be amended in such a way as to “extend the protection it confers”. Article 64(2) EPC also addresses the extent of protection. Pursuant to that provision, if the subject-matter of the European patent is a process, the “protection conferred” by the patent shall “extend” to the products directly obtained by such process. In view of the wording of these two provisions and the Enlarged Board’s statement in G 2/88, Reasons 5.1, the present Board considers that assessing a possible extension of a patent’s scope of protection under Article 123(3) EPC must include possible changes of the scope of protection due to Article 64(2) EPC.”

Applying this principle, the Board concluded that auxiliary request 1 extended the scope of protection beyond that conferred by the granted patent. The addition of a production step to a granted computer-implemented method meant that the amended claim extended to medical implants produced by the method via Article 64(2), whereas the granted claims were limited to a method generating the implant configuration data. Because the amendment captured physical implants that were outside the granted scope, the Board found a violation of Article 123(3) EPC and rejected the request.

Why this matters: the hidden expansion risk in “seemingly narrowing” amendments

At first glance, adding a manufacturing step to a method claim may appear to be a limitation — it introduces additional technical features and appears to narrow the claim to a more specific embodiment.

However, this decision highlights a crucial point in European patent law: the assessment under Article 123(3) EPC is not concerned with linguistic narrowing, but with whether the scope of legal protection has changed in substance, including through the effect of Article 64(2) EPC.

A granted computer-implemented method that produces only data does not automatically protect the physical object represented by that data. Consequently, an amendment introducing a manufacturing step can transform the claim into one that covers the production of a tangible medical device, thereby capturing new categories of infringing subject-matter. This is precisely the type of post-grant shift in protection that Article 123(3) EPC is intended to prevent.

Practical implications for patent drafting and prosecution strategy

This decision has important implications not only in medical technology, but also in broader engineering sectors involving digital design-to-manufacture workflows.

1. Be explicit early about product protection intent

Claim strategy at the drafting stage should match the intended enforcement target. If protection of the physical medical device (e.g. implant, prosthesis, or surgical component) is commercially important, we should ideally include in the application:

• Product claims directed to the implant or device itself
• Method claims explicitly covering manufacturing steps
• Computer-implemented design or configuration claims, where appropriate

A robust approach is to ensure that claim sets cover the full digital-to-physical chain where commercially relevant, since post-grant amendments are likely to fail in extending protection.

2. Beware of “upgrade amendments” in opposition and limitation proceedings

In opposition, patentees may try to save a claim by adding manufacturing steps, especially where infringement is expected at the level of physical production. This decision shows that such amendments can fail if they introduce protection for subject-matter not already covered by the granted claims.

Before introducing manufacturing steps, we should carefully assess:

• Whether the granted claim already implicitly covered the physical product
• Whether Article 64(2) EPC legitimately extends protection to the manufactured object
• Whether the amendment introduces a new category of infringing act (e.g. making a medical implant)

If the amendment effectively shifts protection from a data-processing method to a physical product manufacturing method, it is likely to fail under Article 123(3) EPC.

3. Understand the limits of Article 64(2) EPC

This decision reinforces the often misunderstood interaction between Article 64(2) EPC and Article 123(3) EPC. Article 64(2) EPC extends protection to products directly obtained by a claimed process, but it cannot be used after grant to convert a data-generating method into a product-generating manufacturing process.

Broader significance beyond medical devices

Although this case arises in the context of a medical implant technology, the underlying legal principle is not limited to MedTech. It applies equally to any field where a computer-implemented or simulation-based method generates design data and the physical implementation or manufacturing of a product is performed separately.

This includes, for example, additive manufacturing (3D printing), automotive component design, aerospace engineering, industrial tooling, and CAD/CAM-based production systems.

Conclusion

T 0847/24is a clear reminder that amendments must be assessed not only linguistically but by the protection they confer, including the effect of Article 64(2) EPC.

The key takeaway is straightforward: adding a manufacturing step to a claim originally directed to a computer-implemented configuration method can introduce protection for physical products, such as medical implants, that were not previously covered, thereby violating Article 123(3) EPC. For us, patent practitioners, the decision underlines the value of forward-looking claim drafting that reflects the full commercial lifecycle of the invention, from digital design to physical product.