Sanofi & Regeneron v Amgen - 7 Takeaways from the UPC Court of Appeal

2.    Divergence from the EPO remains possible

The seeming rejection of the EPO’s ‘problem-solution-approach’ to the assessment of obviousness provides ample scope for divergences between the EPO and UPC in their assessment of the same patent. We also note that the UPC has sometimes shown unwillingness to use Rule 295(a) Rules of Procedure (RoP) to stay proceedings where the patent is also subject to EPO opposition proceedings (Carrier Corp. v. Vicot³). This is despite it being made clear that, to the extent the EPO and UPC do diverge, the decision that finds the patent invalid will prevail. This can be contrasted with other cases, such as Meril v Edwards Life Sciences,⁴ where a stay was allowed (overturning the first instance decision) as the EPO’s decision was two months away and this was deemed to satisfy the ‘rapid’ threshold.

However, the CoA was plainly interested in, and considered, the EPO’s Opposition Division (OD) decision when coming to its conclusion, as it is cited in several places in its judgment. It therefore remains to be seen how much divergence will be seen in practice. We note that despite both applying the problem-solution approach and identical prior art, the Munich Central Division’s first instance decision in Amgen v Sanofi & Regeneron found the patent in suit obvious, but the EPO’s OD came to the opposite conclusion, upholding the patent as inventive. The CoA’s decision therefore actually aligned rather than diverged from the EPO’s finding, despite using different “guidelines” when considering inventive step. The EPO OD’s decision is under appeal before the Technical Board of Appeal, so it will be interesting to see what the outcome is on inventive step once this has concluded.

3.    The burden of proof when challenging inventive step is high

As part of the UPC’s holistic test, the CoA stressed that a claimed solution to the objective technical problem is obvious if the skilled person would (not only could) have taken the next step in expectation of finding an envisaged solution to the technical problem. This would generally be the case when “results of the next step were clearly predictable, or where there was a reasonable expectation of success”. This is one part of the guidance that is perhaps most similar to the EPO’s test, which applies a similar “could-would” approach in the latter part of its assessment. The CoA clearly indicates that the burden of proof lies with the party challenging the patent – not only in establishing this is the case on the evidence in the first instance, but also in rebutting any “sufficiently substantiated uncertainties and/or practical or technical difficulties”. This may seem to be difficult to establish based on contemporaneous documents alone, perhaps making expert evidence more crucial and, potentially, the limited cross-examination provided for by the UPCs RoP a more attractive proposition.

4.    Experts

On the topic of experts, it is interesting to note the consideration the CoA gave to the joint statement of the party’s experts prepared for the purposes of parallel Australian proceedings. The joint report was quoted and referred to throughout the inventive step section of the judgment when considering the prior art disclosure, despite the parties submitting separate independent expert declarations in the UPC proceedings.

We note that Rule 181 RoP allows parties to provide any expert evidence that they consider necessary, but does not explicitly provide for joint expert reports or meetings. It does, however, appear that this was something the CoA found useful, and may be something that parties want to consider in the future. We have also seen some Local Divisions take this idea even further, with suggestions for “hot-tubbing” of experts (where both parties’ experts give oral evidence together at the same time) at the oral hearing. This was suggested by the Munich LD in Sanofi v Accord, where the court asked the parties if the experts would be available for hot tubbing and a list of questions were put to the experts concurrently.

Overall, we think reliance on expert evidence for establishing the factual matrix and considering the potential weight to be applied to various factors is important. It should not be forgotten that the UPC CoA is the final arbiter of very important and valuable multinational monopoly rights and it is only proper that the Court basis such decisions on evidence demonstrated to be accurate and complete.

5.    Person skilled in the art

When considering what expert evidence to adduce, it is of note that the CoA interpreted the skilled team very broadly as being someone who explored all areas of drug development, and not just antibodies (despite it being an antibody patent). Such a general framing will also have an impact on the level of common general knowledge that the skilled team has – see for example Mr Justice Meade’s analysis of this under English law in Illumina v MGI⁵.

6.    A further high burden, this time in establishing insufficiency

Similarly to inventive step, the CoA held that the burden of proof to show that the skilled person is unable to reproduce the claimed subject matter rests with the party seeking to invalidate a patent. This seems to be particularly burdensome for broad functional claims, such as those for the patent in suite, where the CoA held that it was necessary for Sanofi and Regeneron to show that the skilled person would be unable to obtain antibodies falling within the claim “in a reliable manner with a reasonable amount of trial and error and without undue burden”. 

In this respect, the CoA noted that Sanofi and Regeneron had argued that the level of proof required was “too high” but said this complaint could be dismissed as “no proof of a failed attempt to obtain suitable antibodies within the scope of the claim” had been adduced. Perhaps, the CoA therefore expected Regeneron to have disclosed certain experiments it had conducted when developing its anti-PSK9 antibody, alirocumab. However, if they were instead indicating that Sanofi and Regeneron should have undertaken litigation experiments, this could prove very difficult given the time and cost involved, the UPC’s deadlines and the ethics of unnecessary animal studies.

For UK practitioners, it should also be noted that the CoA’s approach to insufficiency appears markedly different to that of the UK when considering “breadth of claim” insufficiency attacks. At least for functional features, the CoA established that a patent will not need to disclose every conceivable embodiment within the functional definition to be considered sufficiently disclosed. Importantly, the CoA held that non-availability of some embodiments of a functionally defined claim is immaterial to sufficiency, as long as the skilled person can obtain suitable embodiments within the scope. This could be due to the CoA adopting the approach that the rationale behind the concept of sufficiency is that a patent monopoly cannot be justified if the claimed subject matter cannot be achieved by the skilled person. This differs to the approach in the UK, where the Supreme Court has adopted a broader principle that the patent monopoly must be justified by the patentee’s technical contribution to the art.

7.    Construing functional medical use claims

Finally, important for the pharmaceutical field, is the CoA’s ratio on medical use claims. The CoA held that an “inherent” feature of functional features in medical use claims is that the claimed product must be objectively suitable for the claimed use i.e. therapeutically effective. This requires a “noticeable improvement of the medical condition” or in other words “the treatment must be meaningful”. The CoA considered that it does not matter if the patent specification includes or does not include a minimum required effect. It is through the use of the medical use claim language itself that necessitates a therapeutic effect.

While this appears to set a high standard for establishing sufficiency of medical use claims, we note that in separate UPC proceedings concerning the same parties but a different patent (Sanofi & Regeneron v Amgen⁶) the Düsseldorf LD applied the EPO’s G2/21 ‘credibility’ standard as requiring there to be serious doubts substantiated by verifiable facts about the sufficiency of disclosure of the subject matter claimed in the patent. It will therefore be interesting to see how the UPC’s approach to sufficiency and post‑filed data will develop in the future.

Footnotes:

[1] UPC_CoA_528/2024 and UPC_CoA_529/2024, Decision of 25 November 2025

[2] UPC_CoA_464/2024, Decision of 25 November 2025

[3] UPC CoA 22/2024, Decision of May 28, 2024

[4] UPC_CoA_511/2024, Decision of 21 November 2024

[5] [2021] EWHC 57 (Pat)

[6] UPC_CFI_505/2024, Decision of 13 May 2025