The project to develop a Test Guideline on the Determination of Cytochrome 450 (CYP) Induction using Differentiated Human Hepatic Cells, has resumed at the OECD in September-October 2025, following the completion of additional inter-laboratory comparison work on additional non-pharmaceutical chemicals.
Commenting round on the draft Test Guideline on the Determination of CYP induction using Differentiated Human Hepatic Cells
- Submission period
- 10 November - 19 December 2025
Background public consultation
Project description
The methodology proposed in the draft Test Guidelines relies upon the determination of enzymatic activity involved in the biotransformation of a wide variety of endogenous and exogenous substances in humans. The three CYP enzyme isoforms (CYP 3A4, CYP1A2 and CYP2B6) included in this TG are recommended by the EMA and the US FDA Guidelines for drug-drug interactions studies. 50. The proposed TG is based on the use of a human derived metabolic competent test system (e.g. cryopreserved differentiated HepaRGTM cells). The proposed method was originally validated by EURL-ECVAM and validation was peer-reviewed. The first review at the OECD pointed the need to evaluate more chemicals representative of the future use of the method, i.e. non pharmaceuticals. The United Kingdom took over the project to augment the validation set of chemicals.
How to contribute
The draft Test Guideline is currently under a commenting round by the Working Party of the National Coordinators of the Test Guidelines Programmes and open for comments from the public at the same time. Interested parties are invited to contact their National Coordinators at least a week before 19 December 2025.
