The OECD is currently developing a Detailed Review Paper (DRP) under the OECD Test Guidelines Programme, on test methods for the assessment of liver toxicity using 3D in vitro models, with a focus on human iPSC-based models for regulatory purposes.

This work responds to the increasing need for non‑animal methods for regulatory toxicology and the current absence of OECD Test Guidelines addressing liver toxicity endpoints in 3D liver systems.

The draft DRP includes two chapters:

• Chapter 1 which provides an overview of iPSC technology and of the international efforts undertaken to support the development, characterisation, and standardisation of iPSC-derived models,
• Chapter 2 which focuses on liver microphysiological systems, with particular emphasis on human iPSC-derived liver organoids.

The current consultation is limited to Chapter 1, as the two chapters are being developed on slightly different timelines.

The draft Chapter 1 of the DRP on liver toxicity test method using liver organoids, with a focus on human iPSC-based models for regulatory purposes is currently under a commenting round by the Working Party of the National Coordinators of the Test Guidelines Programme and open for comments from the public at the same time. Interested parties are invited to submit comments to/contact their National Coordinators at least a week before 11 December 2026.

• Draft Chapter 1: Assessment of the scientific and technical maturity of iPSC-based technologies for standardised toxicity testing and review of current recommendations