Interpreting SEQ ID NO:4

Interpreting SEQ ID NO:4: UPC Court of Appeal Upholds Strict Claim Interpretation Standard – Still Not Even a Glimpse of the File Wrapper Estoppel Doctrine

On December 20, 2024, the Unified Patent Court (UPC) Court of Appeal issued an interesting order in Alexion Pharmaceuticals, Inc. v. Amgen (UPC_CoA_405/2024). The ruling upheld the dismissal of Alexion’s request for provisional measures, emphasizing a stringent standard for claim interpretation and corrections in European patent law.

Claim Interpretation and Corrective Standards

At the core of the dispute was the interpretation of claim 2 of Alexion’s patent, which involved an antibody with a light chain designated as SEQ ID NO:4. The Court of Appeal held that claim interpretation must be based on the perspective of a person skilled in the art at the time of the patent’s filing. Critically, corrections to claims are permissible only if the existence of an error and the precise correction are indisputably clear to the skilled person.

The Court rejected Alexion’s argument that the skilled person would recognize and correct a presumed error in SEQ ID NO:4 by excluding its first 22 amino acids, associated with a signal peptide. This finding diverges from the first instance and aligns with a prior EPO Board of Appeal decision ruling on the patent, emphasizing the need for high certainty in claim corrections to ensure legal clarity for third parties.

Validity Concerns Undermine Injunction

Although infringement of the patent was established, the Court concluded that the validity of claim 2 was insufficiently certain to grant provisional measures. Evidence indicated that the light chain as claimed, including the first 22 amino acids, might lack the necessary functionality to bind the targeted component (C5), raising doubts about the patent’s sufficiency of disclosure under Article 83 EPC. The Court also noted that Alexion’s own submissions during the EPO examination proceedings further undermined its current arguments. Notably, though, the Cort of Appeal did not see those submissions as being binding in any way, similar to the idea of the file wrapper estoppel in the USA.

Key Takeaways

• High Bar for Claim Corrections: The decision reinforces a strict approach to correcting claim errors. The correction must be indisputably clear to the skilled person based solely on the patent’s language, description, and common general knowledge.
• Alignment with EPO Board of Appel Standards: The UPC CoA aligns its approach with EPO BoA case law and diverges from the first instance.
• Submissions during Examination of the Patent: The decision highlights the importance of carefully crafting submissions during the examination and grant process of the patent. While the Court of Appeal has not adopted the file wrapper estoppel doctrine (and according to my crystal ball never will), any detrimental statements can and will be used against the patent holder.

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