Stephen Duffield


Stephen’s work has a particular focus on biological therapies, often contentious and involving complex immunological aspects in their mechanisms of action. Stephen’s involvement on these matters ranges from co-ordination and support roles on pan-European litigations, attacking and defending patents in EPO opposition proceedings and on appeal, through to 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 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 biocatalysis, sponsored by DowPharma.

Following his PhD, Stephen worked at GlaxoSmithKline 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.


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