Five biosimilar manufacturers attack Millenium’s Entyvio patents in London

Some of the lawsuits against vedolizumab in the UK date back to early this year. Initially, Fresenius Kabi and Advanz Pharma filed revocation actions in February against most of the patents protecting the biologic (case IDs: HP-2026-000010 and HP-2026-000011). Accord then followed with revocation actions in May (case ID: HP-2026-000019) and then Samsung Bioepis in July (case ID: HP-2026-000028). In August, Celltrion became the last biosimilar manufacturer to file its revocation action with the UK High Court (case ID: HP-2026-000032).

Vedolizumab is a monoclonal antibody used to treat chronic inflammatory bowel diseases such as ulcerative colitis, Crohn’s disease and pouchitis. Millennium Pharma and its parent company Takeda market the biologic under the brand name Entyvio. The claimants are seeking to clear the way for the UK launch of their biosimilar vedolizumab products.

In each of the proceedings, the biosimilar manufacturers have applied for the revocation of various Millennium patents and for declarations of non-infringement or Arrow declarations. Accord, Advanz Pharma, Fresenius Kabi, and Samsung Bioepis are seeking the revocation of EP 3 329 965 and EP 3 311 834. Fresenius Kabi and Advanz Pharma are also seeking revocation of the formulation patents EP 2 704 798 and EP 4 403 579. The patent applications EP 4 378 484 and EP 4 438 625 are also in the crosshairs. Due to their status, these are the subject of Arrow declarations.

Whilst EP 965, EP 834, EPA 484 and EPA 625 all relate to the dosing regimen for vedolizumab, EP 798 and EP 579 relate to formulations. JUVE Patent does not know which of the patents Celltrion has challenged.

Further cases in France and the Netherlands

Fresenius Kabi appears to be at the forefront of the dispute over Entyvio. JUVE Patent has learnt that the company has also initiated related proceedings in France and the Netherlands, and that opposition proceedings are currently underway before the EPO in respect of EP 965. In addition, Advanz Pharma and four straw man claimants are also challenging the validity of EP 965.

At least one other biosimilar manufacturer has also filed invalidity actions against some of the patents in the Netherlands. However, the exact details of these actions are not known at this stage.

James Mellor

The UK High Court intends to hear the four proceedings brought by Accord, Advanz Pharma, Fresenius Kabi, and Samsung Bioepis together. It has scheduled a trial for April 2027. The court will very likely also include Celltrion’s latest claim. In the UK part of the proceedings, the court has already handed down an initial judgment. In July 2026, judge James Mellor ruled in the dispute between Advanz and Millennium regarding the confidentiality regime applying to information concerning Advanz’s IV and SC vedolizumab formulations.

Millennium retains A&O Shearman and Hoyng ROKH

In all UK proceedings, Millennium is fending off the challenges with a team from A&O Shearman. It is understood that the two partners Marjan Noor and Gemma Barrett are leading the cases. At the first hearing concerning Entyvio at the UK High Court, Millennium also relied on the barristers Andrew Waugh and Richard Darby from Three New Square.

In the Netherlands, a team from Hoyng ROKH Monegier took on the defence against the claims brought by Fresenius Kabi. Partners Peter van Schijndel and Theo Blomme are leading the team. Carpmaels & Ransford is also said to be involved in coordinating the proceedings. The firm filed the patents EP 965 and EP 798. Rival firm Hoffmann Eitle filed the other patents.

Fresenius Kabi launched its attacks against Entyvio on both sides of the Channel with the assistance of Winston Taylor and Taylor Wessing. Winston Taylor’s London partner Amanda Ebbutt, as well as the Amsterdam partner Sebastien Versaevel are in charge for the UK and Dutch proceedings. Michael Conway from 8 New Square was also involved as a barrister in the UK proceedings.

Paris based Taylor Wessing partner Jules Fabre and a team consiting of Louise Millot and Clémence de Marassé-Enouf run the French case and handle the European-wide coordination on behalf of Fresenius Kabi.

Pinsent Masons is advising Advanz Pharma in the UK proceedings. The team consists of Charlotte Weekes as lead partner, as well as Sarah Johnson, Alexis Keating, Anna Samokhina, and Robyn Stapelberg. Advanz Pharma’s barristers to date have been 8 New Square’s Charlotte May and Thomas Lunt from Three New Square.

Celltrion’s counsel unknown

A Simmons & Simmons team led by Scott Parker represents Samsung Bioepis. Associates Elsa Glauert and Alexander Kritharidis complete the team, whilst William Duncan of 8 New Square acted as barrister at the first hearing.

Powell Gilbert is advising Accord in the dispute. Tess Waldron and Tim Whitfield are in charge. Theo Cooper, Ioana Sabau, and Gemma Feng complete the team. Barrister Iain Purvis from 11 South Square represented Accord in court.

So far little is known about Celltrion’s claim, as the company only filed it following judge Mellor’s first judgment. However, JUVE Patent has discovered that Tim Harris, a partner at Osborne Clarke, filed the latest claim on behalf of Celltrion. Ben Thomas and Amy Hopkins complete the team. JUVE Patent does not know which barristers will represent Celltrion in court.