title: Performance and data interpretation of the in vivo comet assay in pharmaceutical industry: EFPIA survey results.
abstract: In genotoxicity testing of pharmaceuticals the rodent alkaline comet assay is being increasingly used as a second in vivo assay in addition to the in vivo micronucleus assay to mitigate in vitro positive results as recommended by the ICH S2(R1) guideline. This paper summarizes a survey suggested by the Safety Working Party of European Medicines Agency (EMA), and conducted by the European Federation of Pharmaceutical Industries and Associations (EFPIA) to investigate the experience among European pharmaceutical companies by conducting the in vivo comet assay for regulatory purpose. A special focus was given on the typology of the obtained results and to identify potential difficulties encountered with the interpretation of study data. The participating companies reported a total of 147 studies (conducted in-house or outsourced) and shared the conclusion on the comet assay response for 136 studies. Most of the studies were negative (118/136). Only about 10% (14/136 studies) of the comet assays showed a positive response. None of the positive comet assay results were clearly associated with organ toxicity indicating that the positive responses are not due to cytotoxic effects of the compound in the tissue examined. The number of comet assays with an equivocal or inconclusive response was rare, respectively <1% (1/147 studies) and 2% (3/147 studies). In case additional information (e.g. repeat assay, organ toxicity, metabolism, tissue exposure) would have been available for evaluation, a final conclusion could most probably have been drawn for most or all of these studies. All (46) negative in vivo comet assays submitted alongside with a negative in vivo micronucleus assay were accepted by the regulatory authorities to mitigate a positive in vitro mammalian cell assay following the current ICH S2 guidance. The survey results demonstrate the robustness of the comet assay and the regulatory acceptance of the current ICH S2 guidance.
authors.affiliation: Janssen Research & Development, A Division of Janssen Pharmaceutica N.V., Beerse, Belgium. Electronic address: bvdleede@its.jnj.com.
authors.forename: Bas-Jan
authors.initials: BJ
authors.lastname: van der Leede
authors.affiliation: AstraZeneca, Drug Safety and Metabolism, Cambridge, United Kingdom.
authors.forename: Ann
authors.initials: A
authors.lastname: Doherty
authors.affiliation: F. Hoffmann-La Roche, Pharmaceutical Science, Pharma Research and Early Development (pRed), Basel, Switzerland.
authors.forename: Melanie
authors.initials: M
authors.lastname: Guérard
authors.affiliation: GlaxoSmithKline R&D, Safety Assessment, Ware, United Kingdom.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Howe
authors.affiliation: Consultant Genetic Toxicologist, Nottingham, United Kingdom.
authors.forename: Mike
authors.initials: M
authors.lastname: O'Donovan
authors.affiliation: Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland.
authors.forename: Ulla
authors.initials: U
authors.lastname: Plappert-Helbig
authors.affiliation: Sanofi, Drug Disposition, Preclinical Safety and Animal Research, Vitry sur Seine, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Thybaud
mesh_terms: D000818:Animals; D020552:Comet Assay / Q000379:methods* / Q000706:statistics & numerical data; D004249:DNA Damage; D003625:Data Collection; D004345:Drug Industry / Q000458:organization & administration / Q000706:statistics & numerical data; D005060:Europe; D017408:Guidelines as Topic; D015162:Micronucleus Tests / Q000379:methods; D012377:Rodentia / Q000235:genetics
keywords: Comet assay; EFPIA; Genotoxicity; Regulatory safety testing; Survey