Fresenius Kabi Swissbiosim GmbH & Ors v Millennium Pharmaceuticals, Inc

In patent litigation, managing confidential technical information requires a balance between the receiving party’s access to relevant material and protection of commercial secrecy. No universal confidentiality regime applies. A post-grant prosecution bar may be imposed where there is a non-negligible risk that in-house lawyers will subconsciously use confidential product information when dealing with foreign or EPO claim amendments. Relevant factors include the nature and duration of the secrecy, the recipients’ roles, the difficulty of policing misuse, the organisation’s structure, and the availability of alternative personnel. A bar may be limited to the period of confidentiality and may leave the current proceedings unaffected.

Four coordinated patent actions concerned follow-on patents and applications for vedolizumab. The claimants sought revocation, declarations of non-infringement and Arrow relief in preparation for biosimilar launches. At joint case management conferences, most issues were resolved; the judgment addressed the remaining confidentiality dispute in Advanz’s action.

Advanz proposed to disclose confidential intravenous and subcutaneous formulations to Millennium under a confidentiality club. The parties agreed that two Takeda in-house lawyers could not participate in pre-grant claim drafting. The issue was whether that restriction should also cover their involvement in post-grant claim amendments and auxiliary requests in foreign proceedings and at the EPO. The central question was whether the risk of subconscious use justified the extended prosecution bar.

1. Disposition. The court imposed the extended prosecution bar sought by Advanz. It declined to impose Millennium’s proposed additional conditions requiring fully consolidated validity pleadings or joint leading counsel.
2. Applicable principles. The court applied the non-exhaustive framework in OnePlus v Mitsubishi [2020] EWCA Civ 1562; [2021] FSR 13 and considered the staged, organisation-sensitive approach in InterDigital v OnePlus [2023] EWCA Civ 166. The court must balance access to relevant material against preservation of confidential information. There is no universal form of order. The nature and value of the information, the risk and difficulty of policing misuse, the role of the documents, the receiving party’s contribution and the receiving organisation’s structure are relevant.
3. Risk and evidence. The Advanz formulations were confidential and likely to remain so until around the trial. Ms Cole and Ms Selli had intimate, global involvement in prosecution and enforcement of the vedolizumab portfolio. The court found a non-negligible risk that they would subconsciously use the formulation information when considering post-grant amendments or auxiliary requests. The practical difficulty was analogous to that recognised in Roussel Uclaf v Imperial Chemical Industries (No.2) [1990] RPC 45 (CA).
4. Proportionality. Millennium had not shown that only the nominated individuals could instruct the litigation team. Given Takeda’s size and resources, the court inferred that other suitably qualified personnel were available. The order would not require a significant or impractical business reorganisation, distinguishing General Electric v Siemens Gamesa Renewable Energy [2022] EWHC 490 (Pat). Unlike Merck Sharp & Dohme Ltd v GlaxoSmithKline Biologicals SA [2018] EWHC 3425 (Ch), the bar did not restrict amendments in the current proceedings beyond the baseline reflected in the Civil Procedure Rules 1998. The nominated individuals could not access the formulations while they remained confidential, but Takeda could nominate alternative representatives. The protection would fall away to the extent the information became legitimately public.

not stated in the judgment.