Sanofi vs. Amgen: Success of the first UPCA revocation action and strict assessment of the patentability of therapeutic antibodies

In this case, an action for revocation was brought against the patent EP 3,666,797, one of Amgen's patents concerning PCSK9 antibodies. The first claim of this title concerned an antibody used to treat or prevent hypercholesterolaemia or arteriosclerotic disease, in which the antibody «binds to the catalytic domain of a PCSK9 protein of the amino acid sequence SEQ ID NO: 1, and prevents or reduces the binding of PCSK9 to LDLR». Three Sanofi companies filed a principal revocation action on 1 June 2023, the day the UPC entered into force, before the Munich Local Division of the Central Division of the UPC, while on the same day, a few minutes later, Amgen filed an infringement action against these three companies and Regeneron before the Munich Local Division. Regeneron subsequently filed a counterclaim for revocation, which the Sanofi companies did not do. These are therefore parallel and similar revocation actions before the Central Division and the Local Division, so all parties agreed that the counterclaim for revocation should be referred to the Central Division. These actions take place in a context that is at least rich. Amgen, Sanofi and Regeneron have been fighting since 2014 over Amgen's PCSK9 antibody patents, which reportedly cover both its Repatha and Praluent marketed by Sanofi and Regeneron. Initially, the disputes were brought before national European courts, before being brought before the UPC. A case relating to the US patent corresponding to EP’797 was also brought before the Supreme Court of the United States.

The JUB's decision's main contribution lies in its teaching on the patentability of therapeutic antibodies. The Court first focused on interpreting claim 1, and therefore its interpretation method. First, the Court considers that the person skilled in the art interpreting a claim determines the technical meaning of the terms used with the help of the description and drawings. Then, the Court examines the functional characteristic of the claim «binds to the catalytic domain of a PCSK9». This is about understanding the functional limitation of the claim. The Court considers that for the person skilled in the art, the binding of an antibody has a function, namely to prevent or reduce the binding of PCSK9 to the LDLR. However, in the absence of any indication in the claim or the description that the binding must take place exclusively or mainly within the catalytic domain for the technical function to be achieved, it follows that the person skilled in the art would not have understood it. Furthermore, the Court also considered that the other functional limitation, namely the therapeutic effect of the antibodies (i.e., cholesterol reduction), implied that the claim only concerned antibodies with a therapeutic effect (even if it is «very weak»). Ultimately, the functional language of the claim should not be interpreted as covering «all antibodies capable of binding to the catalytic domain». Such an interpretation shows that the Court appears to want to give more weight to the description than the EPO's Boards of Appeal generally do (e.g., T 169/20, «the support of the description for interpreting the claims should only be used in exceptional cases where the subject matter of the invention and/or its technical context needs to be clarified, and can only be applicable when the invention in the description corresponds to the invention as claimed»).

Secondly, the Court develops its analysis of the inventive step requirementCBE, art. 56It is interesting to note here that the Court chose not to follow the problem-solution approach conventionally used at the EPO, by not starting from the closest, i.e. most promising, prior artEPO guideline G-VII, point 5.1), but only from a realistic starting point. The central division considered that there was an explicit direction in the prior art towards the development of antibodies capable of blocking the link between PCSK9 and LLDR, as a person skilled in the art would have understood from the prior art that blocking this link could be explored for the treatment of hypercholesterolemia. Thus, given this direction, the person skilled in the art would have had a reasonable chance of success in obtaining the antibodies defined by my claims without exercising inventive activity, even if they would have realised that the manufacture of the antibodies and the implementation of screening methods might require considerable time and resources. The court therefore revoked the patent in its entirety (i.e. here for all EPC member states), considering that the person skilled in the art was motivated to develop therapeutic antibodies against PCSK9 and that they would have arrived at the claimed antibodies with a reasonable chance of success without «undue burden» (referring to the time and resources required).

As we have already noted above, the Munich Central Division deviates slightly from the EPO's positions on the interpretation of claims and the assessment of inventive step. Nevertheless, the outcome regarding the patentability of antibodies is close to that of the EPO and therefore also differs from the US approach. The Court's position is close to that of the EPO, which considers that «the subject matter of a claim defining a new antibody that binds to a known antigen does not involve an inventive step, unless a surprising technical effect is demonstrated in the claim or there was no reasonable expectation of obtaining antibodies with the required properties» (EPO guideline G-II-5.6.2Therefore, according to the German local division, in the absence of particular difficulties, the development of antibodies for a known target is routine and thus not inventive. This contrasts with the revocation in the United States, based on the enablement requirement, and where enablement was deemed insufficient because, even from the description, the person skilled in the art had to make an inventive effort to arrive at the millions of antibodies covered, according to the Supreme Court, by Amgen's patents (21-757 Amgen Inc. v. Sanofi (05/18/23)). Ultimately, the UPC establishes a much higher patentability threshold for antibodies in Europe than in the United States.