Dr. Jeroen den Hartog

CounselPatent Attorney

Jeroen is an organic chemist (PhD) and a European and Dutch Patent Attorney. Jeroen specialises in patents, including patent drafting and grant procedures, infringement opinions and oppositions and appeals before the European Patent Office. He also is regularly involved in litigation, he advises on IP strategy, due diligence and national and international licensing. Jeroen’s practice focuses on the chemical and biochemical industries (including the pharmaceutical, processing and food industries).

Jeroen is on the editorial board of Berichten Industriële Eigendom, the leading Dutch specialist intellectual property publication, and publishes widely in the field. He is a Senior Lecturer at the Dutch Institute of Patent Attorneys on the subjects of infringement and freedom to operate.

Before joining HOYNG ROKH MONEGIER, Jeroen worked at a leading international law firm. Prior to this, Jeroen worked for more than 20 years as an in-house patent attorney for DSM, a leading life science and materials company, where he held the chair of corporate patent counsel.

    • Procurement of IP rights. Obtained patents for Tessenderlo, Scelta Mushrooms, ICL, Kleiss, Sulfateq.
    • Oppositions defensive. Defended patents for Tessenderlo, Scelta Mushrooms, ICL, against various parties.
    • Oppositions offensive. Various oppositions and appeals on behalf of above mentioned and other clients; assisting Merck in the field of veterinary medicaments.
    • Opinions and due diligence. For the above and other clients, freedom to operate analysis, validity opinions and due diligence analysis.
    • Litigation support.
    • AstraZeneca v. Sandoz. Assisting in the case for AstraZeneca in relation to the generic infringement of their Faslodex breast cancer patents, confirming the validity of these patents in appeal and securing an injunction.
    • Ceva v. Bayer IP. Defend Ceva against infringement allegations; successfully got the patent revoked in the Netherlands; assisting in opposition before the TBA of the EPO.
    • AbbVie. Several matters on biologics.
    • Essity. Litigation and advise on several matters relating to paper dispensers.
    • Licensing Executives Society (LES)
    • Institute of Professional Representatives Before the European Patent Office (EPI)
    • Dutch Patent Attorney Association
    • European Patent Litigators Association (EPLIT)
    • Update of commentary to sections of the Dutch Ptent law (Tekst en Commentaar) 2019.
    • Comments to the decision on pemetrexed (Fresenius/Eli Lilly 8 May 2018; Court of Appeal The Hague): doctrine of equivalents and file wrapper estoppel or foreseeable equivalents BIE March 2019.
    • “Inventive Step”, Chapter in e-book IEC-digitaal (2016).
    • Comments on plausibility of a technical effect, Court of Appeal, The Hague 26 April 2016; (Ajinomoto / Global Bio-Chem) IEF 15914; nr. 41 2016 BIE oktober 2016.
    • Comments on scope of protection, Supreme Court decision 5 February 2016 (Bayer/Sandoz); IEF15677; J.H.J. den Hartog nr. 15 2016 BIE april 2016.
    • Professional training for patent attorneys; inventive step, May 2019.
    • Professional training for patent attorneys: Infringement and invalidity opinions, June 2019.
    • “He takes a pragmatic, business-centric approach to every matter.” IAM Patent 1000 2021
    • “Jeroen den Hartog provides concise and tactical guidance informed by excellent subject-matter and commercial knowledge.” IAM Patent 1000 2020
    • “Jeroen’s extensive in-house experience grants him a strong strategic and commercial sense and a pragmatic outlook.” IAM Patent 1000 2019
    • “Organic chemist Jeroen den Hartog has immense experience in EPO matters and recently represented Procter & Gamble on several notable prosecutions.” IAM Patent 1000 2016

Assistant details

Visit us

Visiting address:

Rembrandt Tower, 30th Floor
Amstelplein 1
1096 HA Amsterdam
The Netherlands

Postal address:

P.O. Bo 94361
1090 GJ Amsterdam
The Netherlands

The facts


Dutch, English, German, French


University of Leiden (PhD, Chemistry, with honors, 1985)

University of Leiden (Organic Chemistry, 1981)