Partner, Patent Attorney


Wilhelmus (Willum) deals with patent drafting, prosecution and opposition in all key jurisdictions. His particular area of focus is the pharmaceutical sector, where he has extensive experience working on small molecules for therapy of a range of indications, and spanning early drug discovery projects through to clinical candidates.

Areas of Expertise

  • NCE’s
  • Salts, solvates, crystal forms
  • Formulations
  • Treatment regimens
  • Combination therapies


Willum works with a broad range of clients – primarily in the UK, Europe, and the US. They include universities and spin-out companies, as well as large multinational pharmaceutical corporations.


He has a BSc (Hons.) in chemistry from Queens University in Canada and a PhD in chemistry from the University of Cambridge, and subsequently held a post-doctoral fellowship at Stanford University in the US.

Willum joined Mewburn Ellis LLP in 1999, after working as a US patent agent for five years. He qualified as a Chartered Patent Attorney in 2004 and as a European Patent Attorney in 2005. He joined the partnership in 2005.

He has been a tutor at the Centre d’Études Internationales de la Propriété Intellectuelle (CEIPI) since 2004 and continues to lecture prospective European patent attorneys in Strasbourg on an annual basis.


Described as “very good at grasping and summarising problems in the chemistry field... He is also highly regarded for his work on pharmaceutical and polymer patents.”

Client feedback: “Thank you so much for everything you’ve done for the project so far. We couldn’t have got the compound to this stage without you”.  UK based Drug Discovery Company