ICCVAM Biennial Report 2024-2025

ICCVAM member agencies participate in the development and review of chemical testing guidelines issued by the Test Guidelines Programme of the Organisation for Economic Co-operation and Development (OECD) and collaborate on projects supporting the Integrated Approaches to Testing and Assessment (IATA) case studies program under the Working Party for Hazard Assessment. OECD test guidelines (TGs) and related documents are used by government, industry, and independent laboratories of the 38 OECD member countries to assess chemical safety. The U.S. National Coordinator for the OECD Test Guidelines Programme, who is a member of ICCVAM, facilitates the development, review, and clearance of a comprehensive U.S. interagency position for all draft test guidelines, guidance documents, project proposals, workshop reports, and other documents of the supported programs. The National Coordinator also coordinates expert group membership and project leadership for U.S. sponsored projects. The National Coordinator heads the delegation that represents the United States at the annual meeting of the Working Group of National Coordinators and in other test guideline development activities. One or more ICCVAM subject matter experts may join the National Coordinator at this meeting.

In 2024 and 2025, ICCVAM agencies actively participated and commented on draft OECD documents through the National Coordinator. ICCVAM members and/or NICEATM staff also supported a wide range of OECD activities during 2024 and 2025, such as:

• Supporting OECD activities to revise Test Guidelines Programme resources and processes to better support the uptake of emerging technologies, particularly for in silico methods. Efforts are ongoing to develop criteria for evaluation of in silico methods in defined approaches.
• Co-leading a project and participating in an OECD expert group coordinating revision of Guidance Document 34 on validation and acceptance of new or updated test methods for hazard assessment. ICCVAM experts participated in one in-person meeting for the drafting of the document in December 2025, in addition to ongoing virtual meetings. ICCVAM members are leading drafting of revised chapters on the essential elements of validation, the design and conduct of validation studies, and developing readiness criteria for methods undergoing validation. It is anticipated that the revised guidance document will be submitted for approval in the 2027 review cycle.
• Participating in a workshop on operation and financial aspects of validation under the OECD Test Guidelines Programme. The workshop was part of broader discussions aimed at strengthening regulatory confidence and modernizing validation processes for new and emerging chemical safety testing methods. Key points included the need for increased public funding for validation activities, particularly independent peer review, and improved visibility of existing validation resources and expertise to better support and guide method developers in facilitating validation efforts.
• Contributing to a proposal to update OECD TG 496 for in vitro test methods to identify eye irritants. TG 496 was updated in 2024 to add the OptiSafe test method.
• Leading a project to update OECD TG 497 for defined approaches to identify skin sensitizers. TG 497 was updated in 2025 to allow in vitro and in chemico methods in TGs 442C, 442D, and 442E to be used as alternate sources of information. The update also expands TG 497 to include Skin Allergy Risk Assessment–Integrated Chemical Environment (SARA-ICE), a defined approach for the determination of points-of-departure for skin sensitization potential.
• Leading a project to develop a Detailed Review Paper to “Facilitate the Development of Non-animal Test Methods to Predict the Respiratory Sensitisation Potential of Low Molecular Weight Chemicals.” The paper will support the development of an IATA for respiratory sensitization. The Detailed Review Paper was submitted to the Working Group of National Coordinators for the 2026 review cycle. An IATA project was submitted to the Working Party on Hazard Assessment for inclusion on the 2026 work plan. 
• Co-leading a project with the OECD and the European Food Safety Authority to develop an IATA framework template specifically for developmental neurotoxicity. The project will build on the existing developmental neurotoxicity IATA case studies, support the development of new ones, and provide guidance on in vitro to in vivo extrapolation, as well as standardizing uncertainty analysis and data integration within weight-of-evidence assessment. The project was approved by the Working Party on Hazard Assessment in June 2024.
• Participating in a group developing a case study on the use of an IATA for identifying systemic toxicity, which has been submitted to the OECD Working Party on Hazard Assessment.
• Serving as members and cochairs of the Developmental Neurotoxicity Expert Group. In December 2024, a “Workshop on Critical Innovations in Pesticides Safety Testing and Chemical Risk Assessment for Developmental Neurotoxicity” was convened, cochaired by U.S. experts alongside representatives from OECD and the European Food Safety Authority. The workshop examined key challenges identified through regulatory case studies, with the goal of defining priority questions and action items to be addressed in the short to medium term for regulatory implementation. Its overall aim was to support a more efficient regulatory framework by advancing the use of NAMs for assessing developmental neurotoxicity risks, particularly for chemicals and pesticides. 
• Participating in expert groups that are evaluating methods to assess thyroid disruption, skin sensitization, respiratory sensitization, and defined approaches for skin sensitization.
• Participating in an advisory group on emerging science in chemicals assessment.