Marks & Clerk

Firm overview:

Known as one of the UK’s biggest IP firms, Marks & Clerk combines full-service patent prosecution capabilities with deep specialist insight, particularly in the life sciences and high-value technology sectors. Established in 1887 and headquartered in London, the firm operates through 15 offices globally, including eight of the UK’s most innovative cities. The team includes over 300 patent attorneys and solicitors across Europe, Asia, and North America.

The firm is recognised for delivering multidisciplinary teams that integrate technical know-how (spanning biotech, pharmaceuticals, electronics, AI, and medical devices) with strategic litigation and transactional acumen. Its structured and quality‑assured approach ensures responsive support across prosecution, opposition, validity, infringement, and licensing work.

Marks & Clerk is consistently ranked among Europe’s elite for patent prosecution and life sciences litigation. It earns praise for combining strategic insight with robust representation, particularly in biotech and medical devices. The firm is often cited alongside peers Dehns, Carpmaels, and J A Kemp for early involvement at the Unified Patent Court (UPC).

Team overview:

Marks & Clerk’s leadership includes seasoned UPC and European Patent Office representatives, among them Simon Mounteney, Thomas Prock, and Jonathan Stafford, who bridge technical specialisation with court-ready advocacy.

Life sciences litigation is anchored by Mike Gilbert, who is praised by his peers for his work on vaccine-related nullity actions. Other notable partners include Gareth Williams, known for his expertise in genetics. The firm’s UPC taskforce, including attorneys like Jonathan Stafford and partners Mike Gilbert and Charlie Balme, has rapidly built visibility in unitary patent litigation.

Key matters:

• Meril v Edwards Lifesciences

Marks & Clerk co-represented Meril in the UPC’s first full revocation hearing (June 2024) over medical-device patents (EP 3 646 825), with Jonathan Stafford and Charlie Balme leading advocacy—demonstrating cross-border litigation proficiency.

• Pfizer v GSK (UK High Court & UPC)

The firm successfully handled Pfizer’s nullity suit, leading to revocation of two GSK RSV-patent families in the High Court (October 2024) and coordinating ongoing UPC proceedings. Led by Mike Gilbert, the victory secured an Arrow declaration and cleared the way for continued vaccine distribution in the UK.

• Sumi Agro v Syngenta (UPC herbicide dispute)

Led by Gareth Williams, Marks & Clerk is handling parallel infringement and preliminary injunction proceedings before the UPC’s Munich Local Division—highlighting its growing strength in chemical and agricultural patent disputes.

Clients:

Pfizer, Sumi Agro, Meril Life Sciences, Broad Institute, Gilead, Daiichi Sankyo.