Stephen Duffield


Described as “simply a super patent attorney(JUVE 2023), Stephen is a Partner in the Life Sciences team and manages the firm’s Munich office. He is qualified as a patent attorney and as a solicitor, and is a registered UPC representative. Stephen brings each of these perspectives to the matters on which he works, where he has a particular focus on biological therapies. This work is often contentious and relating to therapies involving complex immunological aspects in their mechanisms of action. Stephen is regularly entrusted by clients with matters relating to blockbuster products. These clients recognise his key skills in distilling the complexities of their matters into easily understood arguments for use at the EPO, and in courts and patent offices across Europe. In this respect, industry guides remark that Stephen is “incredibly smart, creative and responsive” and “very knowledgeable about EPO opposition issues and strategy (IAM Patent 1000 2023).

Stephen is regularly involved in UK and pan-European litigations, attacking and defending patents in EPO opposition proceedings and on appeal, and pressure testing patents before their assertion in litigation, including in the anti-TNF, anti-IL12, anti-IL23, anti-PCSK9, anti-IL4R and anti-CD38 fields as well as the immuno-oncology arena (immune checkpoint inhibitors and T-cell retargeting bispecifics). He also has an extensive prosecution and advisory practice relating to patent applications in Europe and across the globe, SPCs and regulatory exclusivities, encompassing biosimilars.

Stephen is often sought out by clients for due diligence and freedom to operate matters, for his ability to assemble and focus teams to achieve results in commercially critical timeframes. He has a real understanding of the business drivers of his work, which was developed through a six-month secondment working in-house at the US patent law department of a global pharmaceuticals company.

When qualifying as a patent attorney, Stephen was awarded the prestigious Gill Prize for achieving the highest overall mark in his final UK qualification exams, as well as the Michael Jones Prize for achieving the highest mark in the finals level patent prosecution paper. Earlier, Stephen was awarded the Bill Caro Prize for the highest mark when passing the Certificate in Intellectual Property Law at Queen Mary University of London.

Stephen graduated with a first class degree in Natural Sciences (Genetics) from Cambridge University and during his studies he picked up a series of college prizes and scholarships for outstanding academic achievement, culminating in the university J. M. Thoday prize for Genetics for graduating with the highest mark. As a result he was also awarded the Emmanuel College Master and Tutors’ Prize. He stayed on at Cambridge to undertake his PhD studies in the field of stereoselective biocatalysis, sponsored by DowPharma.

Following his PhD, Stephen worked at GlaxoSmithKline (GSK) in antibody discovery and engineering. Here he trained in the wet-lab techniques that underpin the matters he works on day-to-day, from phage display to assays for the biophysical and functional characterisation of the antibodies he made. His work at GSK led to patent applications for anti-TNFR antibody-based molecules.

Stephen also sits on the Chartered Institute of Patent Attorneys (CIPA) litigation committee which assists the UK IPO by commenting on draft legislation and coordinates litigation training for UK patent attorneys.

Outside of work, Stephen enjoys snowboarding and listening to live music.


UK Practitioner of the Year
Managing IP Awards 2023


  • MA Natural Sciences (University of Cambridge)
  • PhD (University of Cambridge)
  • LLM (Nottingham Law School)
  • Chartered Patent Attorney
  • European Patent Attorney
  • Irish Patent Agent
  • Solicitor
  • UPC Representative

Key Cases

  • Tecvayli® – Janssen Biotech v Amgen
  • Darzalex® – Janssen Biotech v multiple biosimilar opponents; Janssen Biotech v MorphoSys
  • Stelara® – Janssen Biotech v AbbVie; Stelara® – Janssen Biotech v multiple biosimilar opponents
  • Tremfya® – Janssen Biotech v multiple opponents
  • Dupixent® – Regeneron v Amgen
  • Praluent® – Regeneron v Amgen; Regeneron v Furo Ventures