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Overview of the Latest Scientific Developments on Animal Models and Alternatives Dr Philip A Botham Global Head of Human Safety Syngenta.

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Presentation on theme: "Overview of the Latest Scientific Developments on Animal Models and Alternatives Dr Philip A Botham Global Head of Human Safety Syngenta."— Presentation transcript:

1 Overview of the Latest Scientific Developments on Animal Models and Alternatives Dr Philip A Botham Global Head of Human Safety Syngenta

2 Animal Models for What ? Its not just about toxicology / safety evaluation

3 Statistics of Scientific Procedures on Living Animals : Great Britain 2000 Total number of Procedures 2,714,726 Total number of animals used 2,642,993 àTotal number of toxicology procedures 454,904 (16.8%) n Total number of toxicology procedures for Cosmetics and Toiletries 0 n Total number of acute lethal tests in the rat (LD50/LC50) 2292 àTotal number of Procedures in Dogs 7,632 (0.3%) àTotal number of procedures in primates 3,690 (0.1%)

4 The vast majority of animals used in the European Union are used in: àFundamental biological research àApplied research in human medicine and dentistry àApplied research in veterinary medicine àBreeding programmes, especially for genetically modified animals

5 The Use of Animals in Toxicology – Mandatory Tests For all industry sectors (pharmaceuticals, agrochemicals, industrial chemicals, cosmetics, household products) àRegulatory requirements for conducting clinical trials, registration, safe manufacture, transport àAssess hazard not risk àWide range of complex hazard endpoints (acute, chronic, reproductive system, cancer, teratogens, sensitisers) àNew endpoints / tests (nervous system, immune function, susceptible human sub-populations, e.g. children)

6 The Use of Animals in Toxicology - Elective Tests Compound selection in discovery (active ingredient) and formulation (product) development Mechanistic studies – are findings seen in mandatory tests in rodents / dogs relevant to man? Research studies – understanding generic mechanisms, e.g. how certain chemical classes cause cancer

7 Future Trends in Laboratory Animal Use in Toxicology New toxic endpoints – more testing More products of biotechnology / fewer traditional chemicals – change in testing requirements Greater emphasis on understanding mechanism of toxicity àRelevance of animal models àTransgenics (humanisation of models) àUse of in vitro and in silico technology Public and regulatory expectation for safer drugs pesticides, chemicals and food and for reduced animal use.

8 Toxicology offers both a threat and an opportunity for reduction, refinement and replacement alternatives to animal experimentation

9 What Progress Has Been Made ? Replacement àSkin corrosion àPhototoxicity àSkin permeability Refinement / Reduction àAcute oral toxicity àSkin sensitisation INVENTION TO REGULATORY ACCEPTANCE TOOK 15 – 20 YEARS

10 What Tests Are in Development or Validation? Available within 3 years àAcute oral toxicity (in vitro – screening/dose-setting for in vivo studies) àSkin irritation (in vitro - replacement) àDevelopmental toxicity (in vitro-screening for moderate to strong teratogens) Available within 5 – 10 years àEye irritation (in vitro – replacement) àAcute dermal and inhalation toxicity (in vivo – refinement / reduction) àRespiratory sensitisation (in vivo – new endpoint)

11 In-Vitro Replacement Tests Available Only in Longer Term (more than 10 years) Acute toxicity Skin and respiratory sensitisation Kinetics and metabolism Target organ / system toxicity Developmental and reproductive toxicity Non-genotoxic carcinogenesis

12 Is this pessimistic or too conservative ? Why does it take so long to develop and validate alternatives ? Would more investment in alternatives speed up progress ?

13 Stages in the Development of New Toxicology Test Methods StageOutcomeScience or Technology ResearchUnderstanding basic toxic or biological mechanisms Science Method Development New methods for specific applications Science Pre – ValidationOptimised transferable protocol Technology ValidationEstablishment of reliability and relevance Technology ReviewIndependent scientific peer review - Regulatory Acceptance Regulatory agency decision on acceptability for specific application -

14 Technology can be driven to a timetable by the application of sufficient resources and management skills, while science has a pace of its own IFH Purchase, 1996 Regulatory acceptance also has a pace of its own, and is perceived to be driven as much by politics as by science PA Botham, 2002


16 I know, lets invent the Ames test

17 Would More Investment in Alternatives Speed up Progress ? Yes – by giving more support for conduct and management of high quality validation studies Yes – by encouraging test developers to better understand the needs for hazard and risk assessment in toxicology (more collaboration between academics and industry) No – by funding poorly – conceived or poorly - conducted test development

18 Test Development – A Current Example of Expectation Not Matching Reality Genomics, Transcriptomics, Proteomics and Metabonomics

19 Genomics, Transcriptomics, Proteomics and Metabonomics (GTPM) Mechanistic toxicology; improve relevance to man Predictive toxicology; biomarkers for particular toxic endpoints or classes of toxiciant Can be used with in vitro culture systems

20 The Problems with the Development of GTMP Technology in Toxicology e.g. Using transcriptomics (toxicogenomics) Changes seen genuine adverse effects or healthy adaptive or repair responses? Effects seen at very low doses (relevance ?) Generic problems with the use of in vitro culture systems àTranscript changes may not reflect what would happen in an organ in vivo n Different microenvironment n Lack of cellular interactions n Inadequate or inappropriate metabolism

21 The appropriate application of these techniques is more demanding of careful experimental design than ever, as the potential to generate incomplete and misleading data is great. The attainment of common ground through collaboration involving the generation, sharing and publication of suitable, high quality, data should be prime goal for scientists and institutions engaged in researching the new technology and its appropriate application towards improving the knowledge of the interaction of chemicals with living things. B Pennie, 2001

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