Amgen v Sanofi-Aventis Deutschland (CoA, 25 November 2025)

Dhenne Avocats · 10 October 2026

Our analysis

Summary

By decision of 25 November 2025, given in the joined appeals UPC_CoA_528/2024 and UPC_CoA_529/2024, the Court of Appeal set aside the decisions of the Munich Central Division of 16 July 2024, which had revoked Amgen’s EP 3 666 797 (antibodies against PCSK9) in its entirety on Sanofi’s action and Regeneron’s counterclaim, and rejected the requests for revocation. It dismissed the added matter and insufficiency objections and held the claims not obvious, departing from the Central Division (paragraphs 139 and 210). The decision matters for pharmaceutical practice on three points: the implied therapeutic effect of medical use claims, the sufficiency of functional claims, and reasonable expectation of success.

Facts and procedure

Sanofi filed a revocation action on 1 June 2023, Regeneron filed a counterclaim for revocation, the two being heard together by the Central Division while Amgen’s infringement action was stayed (paragraphs 25 and 26). Claim 1 covers a monoclonal antibody, or fragment, for treating or preventing hypercholesterolaemia, which binds the catalytic domain of PCSK9 and prevents or reduces its binding to the LDLR (paragraph 6). In parallel, the EPO Opposition Division rejected the opposition on 21 May 2025 (paragraphs 7 and 8). On appeal, the 9 January 2008 priority is no longer disputed (paragraph 34).

The applicable law

The grounds for revocation are those of Art. 65 UPCA and Art. 138(1) EPC: added matter (Art. 123(2)), insufficiency (Art. 83) and lack of inventive step (Art. 56). Claims are construed under Art. 69 EPC and its Protocol. The burden of proof lies on the party alleging invalidity (Arts 54 and 65(1) UPCA, Rules 25.1 and 44).

Question

Does a medical use claim require a specific therapeutic effect? Is the patent sufficiently disclosed and inventive over Lagace, given that PCSK9’s extracellular role had not been established at the priority date?

Decision

Dependent claims inform the main claim only case by case (paragraph 46). A medical use claim implies therapeutic effectiveness, meaning a noticeable improvement in the patient’s condition, with no numerical threshold (paragraphs 47 to 49). Added matter is rejected for all the claims challenged, the application being read as a whole (paragraphs 52 to 102). Sufficiency is upheld: a functional claim need not enable every embodiment, and Sanofi and Regeneron failed to show that an antibody within the claim could not be obtained without undue burden (paragraphs 103 to 121).

On inventive step, the Court defines the skilled person as a drug discovery and development team (paragraphs 35 to 37) and frames the problem without reference to PCSK9 or antibodies, to avoid hindsight (paragraph 38). A next step is obvious if its result was clearly predictable or there was a reasonable expectation of success. The burden lies on the party alleging invalidity, but shifts where the patentee substantiates technical uncertainties (paragraphs 133 to 137). Lagace is a realistic starting point alongside Graham (paragraphs 141 to 144), but since it was not known at the priority date whether PCSK9 acted mainly outside the cell, the skilled person could not reasonably predict that an antibody would be therapeutically effective. The Central Division was wrong to treat that question as irrelevant (paragraphs 166 and 203 to 205). Neither parallel industry work nor the combination with Zhang alters this, and Kwon, published after the priority date, cannot be taken into account (paragraphs 206 and 207).

The appeal was allowed and the revocation requests were rejected (paragraph 210). Sanofi and Regeneron bear Amgen’s costs in both instances. Each must pay it the agreed sum of EUR 1,375,000 for the first instance within seven days of the Rule 118.8 notice, and bear the costs of the appeal. The value of each appeal was set at EUR 100 million (paragraphs 211 to 213).

Key points for practice

• Therapeutic effect is an implied feature of every medical use claim, assessed without a threshold but by reference to a clinically noticeable improvement.
• A reasonable expectation of success requires a rational prediction based on known facts. Parallel work by other teams does not in itself establish it (paragraph 138).
• Post-priority publications cannot be used to reconstruct the skilled person’s knowledge (paragraphs 195 to 198 and 207).
• Practical point: a patentee who substantiates the scientific uncertainties at the priority date with precision obliges the revocation claimant to show that they did not prevent a reasonable expectation of success.

Provisions applied

Agreement on a Unified Patent Court

Arts 54, 65(1) and 69

Rules of Procedure

Rules 25.1, 44 and 118.8

European Patent Convention

Art. 56, 69, 83, 123(2) and 138(1)

Case law cited

NanoString v 10x Genomics, Court of Appeal, 26 February 2024, Abbott v Sibio, Court of Appeal, 14 February 2025.

Related decisions

• Sanofi-Aventis Deutschland v Amgen, 16 July 2024, the Central Division decision under appeal.
• Regeneron Pharmaceuticals v Amgen, 16 July 2024, the decision on Regeneron’s counterclaim.
• Sanofi-Aventis Deutschland v Amgen, 18 February 2026, order on suspensive effect of an application for rehearing of this decision.
• Sanofi-Aventis Deutschland v Amgen, 25 March 2026, withdrawal of the applications for rehearing.

Prepared by Dhenne Avocats from the official decision, consulted on 10 October 2026. The database is updated every week, on Friday. Only the official text is authoritative.