Ilja is Counsel in the intellectual property practice at De Brauw Blackstone Westbroek. Ilja was an associate with De Brauw from 1995 to 2003, after which she was with UK firm Bristows for a year. She joined pharmaceutical company AstraZeneca in 2004, first as General Counsel and later was appointed Vice President Corporate & Legal Affairs. Ilja re-joined De Brauw in 2012 as Counsel. Her focus in the intellectual property practice will be predominantly trademarks, marketing & advertising and medicines.  

Ilja is a member of the board of the Pharmaceutical Law Association (VFenR) and is an active member of several national and international professional associations. She regularly lectures on pharmaceutical law.