title: Considerations on photochemical genotoxicity. II: report of the 2009 International Workshop on Genotoxicity Testing Working Group.
abstract: A workshop to reappraise the previous IWGT recommendations for photogenotoxicity testing [E. Gocke, L. Muller, P.J. Guzzie, S. Brendler-Schwaab, S. Bulera, C.F. Chignell, L.M. Henderson, A. Jacobs, H. Murli, R.D. Snyder, N. Tanaka, Considerations on photochemical genotoxicity: report of the International Workshop on Genotoxicity Test Procedures working group, Environ. Mol. Mutagen., 35 (2000) 173-184] was recently held as part of the 5th International Workshop on Genotoxicity Testing (IWGT) meeting in Basel, Switzerland (August 17-19, 2009). An Expert Panel was convened from regulatory, academic and industrial scientists (with several members serving on the original panel) and chaired by Dr Peter Kasper (BfArM, Germany). The aim of the workshop was to review progress made in photo(geno)toxicity testing over the past decade; a period which saw the introduction of several regulatory photosafety guidances in particular in Europe and the USA. Based on current regulatory guidelines a substantial proportion of compounds trigger the requirements for photosafety testing. Moreover, there has been growing concern within industry about the performance of the in vitro photosafety tests in the "real world" of compound development. Therefore, the expert group reviewed the status of the current regulatory guidance's and the impact these have had on compound development in the context of the various triggers for photosafety testing. In addition, the performance of photogenotoxicity assays (old and new) was discussed, particularly in view of reports of pseudophotoclastogencity. The Expert Panel finished with an assessment of the positioning of photogenotoxicity testing within a photosafety testing strategy. The most significant conclusion made by the Expert Panel was that photogenotoxicity testing should no longer be recommended as part of the standard photosafety testing strategy. In addition, progress was made on the refinement of triggers for photosafety testing. For example, there was support for harmonisation of methods to determine the Molar Extinction Coefficient (MEC) and a consensus agreement that there should be no requirement for testing of compounds with a MEC<1000Lmol(-1)cm(-1).
authors.affiliation: GlaxoSmithKline, Ware, United Kingdom. anthony.m.lynch@gsk.com
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Lynch
authors.forename: Peggy J
authors.initials: PJ
authors.lastname: Guzzie
authors.forename: Daniel
authors.initials: D
authors.lastname: Bauer
authors.forename: Elmar
authors.initials: E
authors.lastname: Gocke
authors.forename: Satoru
authors.initials: S
authors.lastname: Itoh
authors.forename: Abby
authors.initials: A
authors.lastname: Jacobs
authors.forename: Cyrille A M
authors.initials: CA
authors.lastname: Krul
authors.forename: Andreas
authors.initials: A
authors.lastname: Schepky
authors.forename: Noriho
authors.initials: N
authors.lastname: Tanaka
authors.forename: Peter
authors.initials: P
authors.lastname: Kasper
mesh_terms: D000818:Animals; D020552:Comet Assay / Q000379:methods; D004335:Drug and Narcotic Control; D005123:Eye / Q000187:drug effects; D017408:Guidelines as Topic; D015162:Micronucleus Tests / Q000379:methods; D023421:Models, Animal; D009152:Mutagenicity Tests / Q000379:methods* / Q000592:standards*; D055668:Photochemical Processes; D051381:Rats; D018570:Risk Assessment; D012867:Skin / Q000187:drug effects; D018675:Toxicity Tests / Q000379:methods