Experimental Toxicology Services (ETS) Nederland BV, based in Zutphen, Netherlands, is a privately owned toxicology consultancy managed by Henk Tennekes, PhD. ETS ensures high quality monitoring of outsourced toxicology studies in close collaboration with study sponsors, usually R&D departments of pharmaceutical and biotech companies.


Services include custom designed R&D programmes, contract research organisation (CRO) selection, coordination and follow-up of studies, study design and protocol review of in vivo and in vitro studies (such as ADME, toxicology and secondary pharmacology), as well as pharmacokinetic and toxicology data analysis and reporting. ETS mediates between sponsor and CRO, objectively selecting CROs that best suit the needs of the sponsor, and gives the sponsor insight into true costs.

Tennekes is a highly experienced and certified toxicologist, and an expert in risk assessment. He has published authoritative papers in leading scientific journals:

  • Tennekes H and Gretton VA. ‘Hazard and risk assessment of chemical carcinogenicity within a regulatory context’. Cancer Risk Assessment:
  • Carcinogenesis from Biology to Standards Quantification, Hoboken: John Wiley and Sons; 2008.
  • Tennekes H, Gembardt C, Dammann M, and van Ravenzwaay B. Regulatory
  • Toxicology and Pharmacology 40. 2004;pp18-27.
  • Tennekes H, Kaufmann W, Dammann M, and van Ravenzwaay B. Regulatory
  • Toxicology and Pharmacology 40. 2004;pp293-304.
  • Tennekes H, van Ravenzwaay B, and Kunz HW. Carcinogenesis 6. 1985;pp1457-62.
  • Tennekes HA, Edler L, and Kunz HW. Carcinogenesis 3. 1982; 941-45.
  • Tennekes HA, Wright AS, Dix KM, and Koeman JH. Cancer Research 41. 1981;pp3615-20.

Other ETS services include preparation of expert reports, PK summaries, toxicology summaries, contributions to Investigator’s Brochures, Investigational New Drugs, New Drug Applications, dossiers according to Directive 91/414/EEC and Biocidal Product Directive 98/8/EC, and the preparation of manuscripts for scientific journals (ghostwriting).