Evening lecture by Barae Jomaa, PhD, ERT, organized by the 'Chemische Kring Zwolle'.

Endocrine Disruption Testing strategy for REACH: Current gaps and future requirements

Summary
The EU now has dedicated endocrine disruption (ED) hazard classes under its Classification, Labelling and Packaging (CLP) regulation but no REACH information requirements designed to populate them. Since the 2023 CLP amendment, registrants have been expected to reach ED conclusions. They do this from evidence assembled mostly from existing dossier data and published literature which was generated to answer other research questions. Conclusions are supplemented, where possible, by in silico predictions. The standard information requirements in Annexes VII to X remain essentially unchanged.

This presentation examines where that disconnect leaves testing strategy. It maps the estrogen, androgen, thyroid and steroidogenesis (EATS) modalities against what the OECD conceptual framework can currently deliver. The estrogen, androgen and steroidogenesis pathways are served by validated in vitro guidelines. In contrast, thyroid disruption still has no mechanistic test guideline, despite a decade of EURL ECVAM and OECD expert group work and a large inventory of candidate methods. Modalities beyond EATS remain largely uncovered.

With the full REACH revision set aside in April 2026 in favour of targeted annex amendments through comitology, ED information requirements are likely to arrive as a series of technical changes rather than one legislative package. The options discussed so far imply substantial in vivo testing, with published estimates running into millions of animals, sitting uneasily against the last resort principle in Article 25 (testing a substance on animals is permitted only if no other options are available).

The talk covers what a proportionate strategy could look like: tonnage-based triggers, weight of evidence, and the level of validation regulators should reasonably require before accepting a non-animal method in place of an in vivo study.

Biography
Barae Jomaa, PhD, ERT, is Principal Toxicologist and International Regulatory Lead at Colonial Chemical, Inc. With more than 16 years of experience in toxicology, regulatory affairs and scientific communication, he spearheads the company's international regulatory initiatives, focused on safety assessments and substance registrations under global chemical regulations. A European Registered Toxicologist, he holds a PhD in Toxicology from Wageningen University. His doctoral and postdoctoral research developed in vitro assays and integrated testing strategies for thyroid-disrupting compounds, including a human thyroid peroxidase assay that removed the need for animal-derived tissue. That work was published in ALTEX and an Elsevier volume on toxicogenomics-based cellular models. An advocate for animal welfare and environmental protection, he is founder and Editor in Chief of the Journal of the Netherlands Society of Toxicology, and has been Editor in Chief of TCDD, the society's newsletter, since 2015. He speaks regularly at international chemical regulation and cosmetic science conferences on animal-free safety assessment.

Invitees are very welcome.

For further information about the lectures, please contact the CKZ by email: ckzsecretariaat@gmail.com.