Prof. Willem Hoyng


Willem’s practice primarily consists of litigating in the field of intellectual property law.  Willem acts before all the national courts (the courts of first instance, the courts of appeal and the Supreme Court). He also regularly litigates before the Court of Justice of the European Union (CJEU) and the European Patent Office (EPO). Willem is also involved in advising on European patent strategies and coordinating and conducting European patent proceedings. He is the adviser of many innovative Dutch and foreign multinationals, including pharmaceutical and biotechnological companies.

Willem is a professor of Intellectual Property Law at the University of Tilburg.

Willem is one of the founding members of HOYNG ROKH MONEGIER, he was the managing partner of HOYNG MONEGIER from 2011 until 2015, when the firm merged with German IP boutique ROKH IP and stepped down as a managing partner of  HOYNG ROKH MONEGIER in January 2018.

Willem is a member of a select group of lawyers admitted to appear before the Dutch Supreme Court.

Willem is the Chairman of the Advisory Committee of the Unified Patent Court (UPC). He was a member of the drafting committee of the Rules of Proceedings of the UPC and advises the Dutch Ministry of Economic Affairs on UPC matters.

Willem Hoyng has registered Intellectual Property Law and Supreme Court litigation as his principal legal practice areas in the Netherlands Bar’s register of legal practice areas (rechtsgebiedenregister). Based on this registration, he is required to obtain ten training credits per calendar year in each principal legal practice area in accordance with the standards set by the Netherlands Bar.

    • Monsanto v Cefetra. Represented Monsanto in the first patent case (interpretation of the Biotech Directive) before the CJEU.
    • Isover St Gobain v Rockwool. Represented Isover St. Gobain in a patent infringement case lasting 25 years. The Supreme Court confirmed that Rockwool’s patent was invalid and not infringed.
    • Dijkstra v Saier. Represented Dijkstra before the Dutch Supreme Court, which accepted the doctrine of file wrapper estoppel in Dutch patent law. Convinced the Supreme Court to revoke the decision of the Court of Appeal.
    • Van Bentum v Kool. Represented Van Bentum before the Dutch Supreme Court, convincing the court that foreseeable equivalents which the patentee did not claim can still be claimed under the doctrine of equivalents.
    • Mega Brands v Lego. Convinced the Court of Appeal of Den Bosch that, contrary to the earlier decision of the Court of Appeal of Amsterdam, the sale of copies of Lego bricks by Mega Brands should not be prevented under the doctrine of slavish imitation and thereafter convinced the Supreme Court to dismiss Lego’s appeal.
    • Solvay v Honeywell. Argued that Dutch courts can grant cross border injunctions in preliminary injunction proceeding. The ECJ agreed.
    • European Patent Lawyers Association (EPLAW), Co-founder and Former President
    • International Association for the Protection of Intellectual Property (AIPPI), Former President of the Dutch Group
    • IP Advisory Committee of the Dutch Bar, Former Chairman
    • Former member of the Government Advisory Committee on patents
    • Former member of the Supervisory Board of the Academy of the European Patent Organisation
    • Former chairman of the VIEPA, the association of Dutch attorneys specialized in IP matters
    • De Rechtbank is de weg kwijt. Showing that first instance decision in “Pemetrexed” is wrong (June 2019 IE Forum)
    •  Transborder enforcement of patent rights in Europe, Festschrift Thomas Reimann
    •  100 years of the Patent Act in the land of the Polders, A Century of Patents in the Netherlands
    •  Patent Law and the Dutch Supreme Court, Festschrift De Gryse
    •  The allowability of disclaimers, Festschrift Guntram Rahn
    •  Contributory Infringement, Festschrift Brinkhof
    •  Een pleidooi voor enige demassificatie in het Octrooirecht, 200 jaar Iustitia & Amicitia
    •  De Angorakat, Festschrift Spoor
    •  The Dutch Supreme Court and art. 69 EPC, an inspiration for the UPC, liber amicorum Gielen
    • BNA International Patent Litigation Book Netherlands and EU Chapter
    • Volume The interplay between Competition law and Intellectual Property Law – an international perspective. Can an injunction in non SEP cases be contrary to competition rules?
    • Kluwer Law International, Global Patent Litigation – revision Netherlands chapter
    • Dutch chapter tailored injunctions book “injunctions and the turn towards a proportionality-based approach in Dutch patent law”
    • Elgar Publishing “Research Handbook European Patent Law”
    • IER Amicorum Ernst Numann “Voor nu man(n) blijft het “wezen” ernst
    • Festschrift Dr. Sabine Rojahn “From sail to ink cartridges and coffee pads”
    • Kluwer, IRDI UPC re post Duitse beslissing “De UPC Quo vadis”
    • Amicorum Constant van Nispen: Cross-border decisions and the UPC.
    • GRUR, Festschrift Dr. Peter Meier-Beck: Back to the “Erfindungsgedanke“?
    • EPO seminar “Unresolved procedural issues in the UPC” – July 2024
    • IPO European Annual Congress “the UPC after one year” with judge Brinkman – London – June 2024
    • Nederlands Octrooicongres met Bart van den Broek “Eén jaar UPC jurisprudentie” – Amsterdam – June 2024
    • ACI’s Patent Prosecution Program “the UPC” with judge Brinkman – New York – May 2024
    • Pharma & Biotech Patent Litigation in Europe “the UPC one year later” with judge Kupecz – Amsterdam – May 2024
    • Meeting Administrative Committee – Luxembourg – May 2024
    • ACI’s 20th Annual Paragraph IV Disputes Conference “One year UPC” with judge Kalden – New York – April 2024
    • Meeting Advisory Board of the Advisory Committee of the UPC  – Paris – April 2024
    • IPBC Europe 2024, “keynote interview judge Kalden” – Munich – March 2024
    • Willem is a regular speaker at all types of IP dedicated seminars and conferences. Most recently he held the Hugh Laddie Lecture 2019, spoke at the ELI conference in Vienna in September 2019 and the Venice Patent Judges Conference in October 2019/2020, Delex patent course 2020. In February 2021 Willem is chairman for the EPLAW webinar CJEU’s judgment C-688/17 (Bayer) – “a support for innovation or a miscarriage of justice”.
    • Willem is a regular speaker at all types of IP dedicated seminars and conferences. Most recently he held the Hugh Laddie Lecture 2019, spoke at the ELI conference in Vienna in September 2019 and the Venice Patent Judges Conference in October 2019/2020, Delex patent course 2020. In February 2021 Willem is chairman for the EPLAW webinar CJEU’s judgment C-688/17 (Bayer) – “a support for innovation or a miscarriage of justice”.
      • “Hoyng is an encyclopaedia of IP knowledge, having seen and done it all over the course of his nearly 50-year career.” IAM Patent 2022
      • “An authority on patent law.» Chambers & Partners 2022
      • “Hoyng has seen and done it all in the trademark world.» World Trademark Review 2022
      • “He has the gift of explaining complicated things in a very comprehensible and accessible manner.» Chambers & Partners 2021
      • “Extremely experienced, extremely pleasant and always available.” IAM Patent 1000 2021
      • “Hoyng has built the practice into the behemoth it is today and serves as a vital sounding board to patrons and peers alike.” World Trademark Review 2021
      • “A strong fighter, pragmatic, open and direct, as well as strategically very good.” Chambers & Partners 2020
      • “Brilliant strategic thinker” JUVE Patent 2020
      • “Undoubtedly a superlative lawyer and one of the best in the country.” Legal 500 2020
      • “Adept at compressing very complicated issues into comprehensible language. An unrivalled force in the Dutch trademark sphere.” World Trademark Review 2020
      • “Knows the court system inside out.” IAM Patent 1000 2020
      •  “Willem Hoyng is a consistently recognised leader in the field with unrivalled experience and expertise at domestic, European and Supreme Court level.” Chambers & Partners 2019 
      • “He has the most rigorous legal mind and is a top-flight strategic thinker who knows how the courts approach matters. He is the person you need by your side in a big case.” IAM Patent 1000 2019
      • “The best patent lawyer in the Netherlands.” Chambers & Partners 2019 
      • “He’s an extraordinary lawyer who can do anything.” World Trademark Review 2019 
      •  “Willem Hoyng is a “formidable litigator” and an “excellent advocate who is very well known and respected.” Chambers & Partners 2018 
      • “Outstanding” IAM Patent 1000 2017 
      • “The straight-talking Willem Hoyng is the best-known litigator in the Netherlands. He combines so many excellent qualities – he is thorough, persuasive and persistent, and his vast experience makes him an authority whom judges look up to.” IAM Patent 1000 2016 
      • Sources are quick to applaud Willem Hoyng as “really in a different class. He is an extremely strong litigator who immediately drills down to the issue and familiarises himself quickly with all aspects of the case. He has a broad practice and is widely regarded as one of the best patent litigators on the market.” Chambers & Partners 2015 
      • “Absolutely stellar and one of the best patent litigators in Europe. He is able to plead before the Supreme Court and is valued by clients for his presence and impact in the courtroom.” Chambers & Partners 2014
      • “Maybe the greatest litigator there has ever been in the Netherlands” World Trademark Review 2013




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