Mepha v Bristol-Myers Squibb (BPatGer, O2022_007, 2024)

Dhenne Avocats · 11 October 2026

Our analysis

Summary

The Swiss Federal Patent Court dismisses the nullity action against the Swiss supplementary protection certificate for apixaban. It holds that the basic patent validly claims its US priority, which removes the cited prior art, and that apixaban is inventive over WO 00/39131. In admitting post-filed data on factor Xa inhibition, it reads G 2/21 as requiring the effect to be encompassed by, and derivable from, the teaching of the application, without experimental data. It thus departs from the Court of Appeal of England and Wales, which had invalidated the UK part of the same patent, and keeps the burden of proving priority on the proprietor under Swiss law after G 1/22.

Facts and procedure

SPC C01427415/01, granted on 30 April 2014 and in force since 17 September 2022, is based on the Swiss part of EP 1 427 415, whose claim 1 covers apixaban (para. 15). Mepha brought its nullity action on 31 May 2022 (para. 1). During the proceedings the proprietor surrendered claims 5 to 29, directed to therapeutic uses, and the case continued on the limited patent (para. 11). The court notes that an action for nullity of an SPC is open to anyone, without any need to show an interest (para. 13). It sets out the diverging decisions given on the same patent in seven other European countries (para. 14).

The applicable law

Under Article 20(1) of the Patents Act (PatG), the proprietor must prove the existence of the priority right. The court holds that G 1/22 does not displace that rule: the presumption adopted by the Enlarged Board is a matter of assessment of evidence, governed by the law of the forum, and does not bind Swiss courts (paras 27 to 29). Inventive step is assessed under the problem and solution approach (para. 32). It analyses G 2/21 and the subsequent case law of the Boards of Appeal (paras 36 to 38).

Question

Is priority valid where the later application was filed by another group company without a prior written assignment, and may post-filed data support inventive step for a compound in respect of which the application reports no inhibition value?

Decision

On priority, the court adopts the reasoning of G 1/22: since the US provisional application was unpublished, the filing company depended on the cooperation of the first applicant, and the priority right passed to it tacitly when the priority documents were handed over, an informal transfer valid under Swiss law and under the EPC; the expert evidence on Delaware law is immaterial (para. 30). WO 03/049681 is therefore not prior art and claim 1 is new (para. 31).

On inventive step, the court observes that plausibility has no statutory basis and is rooted in the prohibition of abuse of rights, which calls for restraint (para. 39). It rejects a reading of G 2/21 confined to the absence of legitimate doubt, which would not prevent speculative applications, and adopts two cumulative criteria: the effect must be encompassed by the teaching of the application as filed and derivable from it by the skilled person, with no requirement for experimental data, and the bar must not be set too high (para. 39). As the application presents the compounds as factor Xa inhibitors, the first criterion is met (para. 40). It also describes how to measure the inhibition constant (Ki) and states preferred thresholds; measuring the Ki of the 110 examples involves no undue effort and reveals a value of 0.08 nM for apixaban, from which selectivity can also be derived (para. 42). The problem is to provide an effective and selective factor Xa inhibitor (para. 43), and nothing prompted the skilled person to make the many structural changes leading to apixaban (para. 45). The outcome is the same starting from examples 61 and 86 of WO 00/39131 (paras 47 and 48). The action is dismissed in full (para. 49). Mepha bears the CHF 80,000 court fee and CHF 138,500 in party compensation; the proprietor bears the cost of the expert report made necessary by its Delaware law argument (paras 50 to 52).

Key points for practice

• In Switzerland, the proprietor bears the burden of proving valid priority; G 1/22 does not alter Article 20 PatG (para. 29).
• Handing priority documents to a company in the same group may amount to a tacit transfer of the priority right (para. 30).
• A technical effect may be derivable from the application without experimental data where the application provides the means of verifying it on its examples (paras 39 and 42).
• Practical point: as national readings of G 2/21 may produce opposite outcomes on the same patent, derivability should be argued from the concrete indications of the application as filed.

Provisions applied

European Patent Convention

art. 54, art. 87, art. 88, art. 89

National law

Arts 1, 7, 20, 109 and 140k of the Federal Patents Act (PatG); Art. 26 of the Patent Court Act (PatGG); Art. 110 of the Private International Law Act; Arts 106 and 108 of the Swiss Civil Procedure Code

Other provisions

PCT, Rules 4.10 and 17.1

Case law cited

EPO, G 2/21, G 1/22 and G 2/22, T 116/18, T 1989/19, T 2015/20, T 1329/04, T 606/89, T 967/97; Sandoz v Bristol-Myers Squibb [2023] EWCA Civ 472; Warner-Lambert v Generics [2016] EWCA Civ 1006; BGE 133 III 229 (Citalopram I); BGE 138 III 111; BPatGer O2013_011, O2015_007, S2017_001

Related decisions

• Sandoz v Bristol-Myers Squibb, 4 May 2023, UK part of the same patent invalidated for lack of plausibility (para. 14).
• Bristol-Myers Squibb v Sandoz, 15 August 2023, preliminary relief granted in the Netherlands on the same patent (para. 14).
• G 2/21, 23 March 2023, test applied to post-filed data (paras 36 to 39).
• G 1/22 and G 2/22, 10 October 2023, followed on transfer of the priority right, not followed on burden of proof (paras 29 and 30).

Prepared by Dhenne Avocats from the text of the decision (official text, bundespatentgericht.ch), consulted on 11 October 2026. Only the official text is authoritative.