The introduction of the Unified Patent Court ("UPC") has brought renewed attention to the application of second medical use claims, prompting practitioners to consider how the Court approaches these complex and commercially significant patents in light of established EPO and national case law.

Second medical use claims play a crucial role in pharmaceutical patent law, enabling the protection of new therapeutic applications of known substances or compositions. While the active ingredient may already be known, its newly discovered efficacy in treating a different medical condition or a new group of patients may be patentable.

In accordance with the established case law principles regarding the "Swiss claim formulation", such claims were formulated as the "use of substance X for the manufacture of a medication for treating disease Y". However, with the evolution of legal frameworks, particularly under Article 54(4) and (5) of the European Patent Convention ("EPC"), the more direct purpose-limited product claim format "substance X for use in treating disease Y" was established.

Not surprisingly, neither the UPC Agreement ("UPCA") nor the Rules of Procedure contain provisions that specifically address second medical use claims. Consequently, there is so far no harmonised approach within the UPC. As the UPC has only been operating since 1 June 2023, there is currently only one decision that addresses the specific application of claims to second medical uses.

The UPC decision (Düsseldorf Local Division, 13 May 2025, UPC_CFI_505/2024) clarifies several key principles. For second medical use claims, the novelty and inventiveness derive not from the substance itself, but from its specific new therapeutic application. The patent must relate to a defined and novel use, such as a new disease, patient group, or therapeutic indication. The claim's scope is determined by its wording, interpreted in light of the description and drawings. In order to benefit from the notional novelty provided by Article 54(5) EPC, second medical use claims must be directed to a specific use in a method as defined by Article 53(c) EPC. This legal framework creates a "legal fiction" of novelty, where the only justification for patentability is the novelty and inventive step of the new therapeutic use, not the substance itself.

When assessing validity, the Court applies established UPC standards: the claimed use must be directly and unambiguously disclosed in the priority documents, and the invention must not be obvious in light of the prior art. The sufficiency requirement is met if the patent, together with common general knowledge, enables the skilled person to carry out the invention, including achieving the claimed therapeutic effect. Added matter is assessed by whether the combination of features is clearly derivable from the application as filed. In the case of a second medical use claim, the therapeutic effect forms part of the claimed "use" and must therefore be sufficiently and reproducibly disclosed throughout the patent as a whole.

The UPC has stated that infringement requires more than just the offering or selling of the product. Instead, the burden of proof is on the party claiming the product's medical efficacy to demonstrate its intended use and that the alleged infringer was aware of this use. Therefore, both the objective likelihood of the patented use occurring and the subjective awareness of the infringers need to be assessed. This process involves a detailed, case-by-case assessment of market conditions, the scope and significance of the use, and any promotional or preventative measures implemented to safeguard the patented application. While packaging and product information such as the Summary of Product Characteristics ("SmPC") are relevant, they are not decisive on their own. The overall context and the infringer's knowledge remain central to determining liability.

Thus, the UPC does as already known e.g. from the German infringement courts, place a significant burden of proof on the patent holder to provide evidence on the key factors relevant to the case-by-case assessment. However, it remains to be seen how this jurisprudence will further evolve as the detailed requirements for determining the infringer’s knowledge are decisive.