Partner, Patent Attorney
Life Sciences


Katherine specialises in EPO oppositions and appeals, particularly defending patents in complex opposition cases involving very large numbers of opponents.  Her defence of a patent protecting Xolair® against ten opponents in T 99/13 prompted an update of the EPO Guidelines for Examination emphasising the importance of assessing added matter from a technical and reasonable standpoint (read about this significant case in more detail).

Katherine advises on European prosecution strategies for many important patent families, particularly divisional strategies for opposed patents.  Katherine’s prosecution work includes advising on securing grant for the high-profile family of cases protecting CRISPR/Cas platform technology invented by Jennifer Doudna and Emmanuelle Charpentier.

Areas of Expertise

  • Purification and formulation techniques for biological therapeutics, particularly recombinant antibodies
  • CRISPR/Cas
  • Gene therapy, including viral vehicles
  • Complex recombinant antibodies e.g. BiTEs
  • Mitochondrial biology
  • Diabetes


Katherine works for multinational biotech corporations and biotech start-ups.


Katherine has a degree in Biochemistry and Molecular Biology from the University of Cambridge and graduated with the highest score in her class.  She also completed a PhD at Cambridge based in the Medical Research Council’s Mitochondrial Biology Unit.  Her doctoral project investigated the influence of free radicals in efficiency of ATP production.

Katherine joined Mewburn Ellis in 2006, became a Chartered Patent Attorney and European Patent Attorney in 2010, and joined the partnership in 2014.


Katherine’s work advising UC Berkeley, California on their European and UK applications for CRISPR/Cas gene editing technology was noted in Legal 500 2018. She was also recognised as a 'key lawyer' in Legal 500 2021 and 2022.

‘Katherine Green is very dedicated to deliver the best possible position for her clients. She can digs into every detail but keeps the big picture at the same time – very impressive!‘ - The Legal 500, 2022