Physiologically-based Kinetic Modelling (PBK Modelling): meeting the 3Rs agenda. The report and recommendations of ECVAM Workshop 63.

This is the report of the 63rd of a series of workshops organised by the European Centre for the Validation of Alternative Methods (ECVAM). ECVAM’s main objective, as defined in 1993 by its Scientific Advisory Committee, is to promote the scientific and regulatory acceptance of alternative methods which are relevant to the biosciences and which reduce, refine or replace the use of laboratory animals. One of the first priorities set by ECVAM was the implementation of procedures that would permit the acquisition of expertise about the stateof-the-art of non-animal test development and validation, and the potential for incorporating such alternative tests into regulatory procedures. It was decided that this would be best achieved through a programme of ECVAM workshops, each addressing a specific topic, and at which selected groups of independent international experts would review the current status of various types of in vitro tests and their potential uses, and make recommendations about the best ways forward. The workshop entitled Physiologically-based Kinetic Modelling (PBK Modelling): Meeting the 3Rs Agenda was held at ECVAM (Ispra, Italy) on 10–12 October 2005, building upon a programming meeting held at Ispra on 31 May and 1 June 2005. The participants included international experts in PBK modelling and in the risk assessment of chemical products, from academia, regulatory or risk assessment advisory bodies, and industry. The objectives of the workshop were: