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Bourcier T, McGovern T, Cavaliero T, Ebere G, Nishikawa A, Nishimura J, Ogawa K, Pasanen M, Vespa A, Van der Laan JW. ICH S1 prospective evaluation study: weight of evidence approach to predict outcome and value of 2-year rat carcinogenicity studies. A report from the regulatory authorities subgroup. FRONTIERS IN TOXICOLOGY 2024; 6:1353783. [PMID: 38665214 PMCID: PMC11043531 DOI: 10.3389/ftox.2024.1353783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 01/29/2024] [Indexed: 04/28/2024] Open
Abstract
Introduction: The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) initiated a process in 2012 to revise the S1B Guideline "Testing for Carcinogenicity of Pharmaceuticals". Previous retrospective analysis indicated the importance of histopathological risk factors in chronic toxicity studies, evidence of endocrine perturbation, and positive genetic toxicology results as potentially predictive indicators of carcinogenic risk. In addition, a relationship between pharmacodynamic activity and carcinogenicity outcome in long-term rodent studies has been reported. It was postulated that these factors could be evaluated in a Weight-of-Evidence (WoE) approach to predict the outcome of a 2-year rat study. Methods: The ICH S1B(R1) Expert Working Group (EWG) conducted a Prospective Evaluation Study (PES) to determine the regulatory feasibility of this WoE approach. Drug Regulatory Authorities (DRAs) evaluated 49 Carcinogenicity Assessment Documents (CADs), which describe the WoE for submitted pharmaceutical compounds. Each compound was categorized into a carcinogenic risk category including a statement of the value of the 2-year rat study. The outcome of the completed 2-year rat studies was evaluated in relation to the prospective CAD to determine the accuracy of predictions. Results: Based on the results of the PES, the EWG concluded that the evaluation process for assessing human carcinogenic risk of pharmaceuticals described in ICH S1B could be expanded to include a WoE approach. Approximately 27% of 2-year rat studies could be avoided in cases where DRAs and sponsors unanimously agreed that such a study would not add value. Discussion: Key factors supporting a WoE assessment were identified: data that inform carcinogenic potential based on drug target biology and the primary pharmacologic mechanism of the parent compound and major human metabolites; results from secondary pharmacology screens for this compound and major human metabolites that inform carcinogenic risk; histopathology data from repeated-dose toxicity studies; evidence for hormonal perturbation; genotoxicity data; and evidence of immune modulation. The outcome of the PES indicates that a WoE approach can be used in place of conducting a 2-year rat study for some pharmaceuticals. These data were used by the ICH S1B(R1) EWG to write the R1 Addendum to the S1B Guideline published in August 2022.
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Affiliation(s)
- Todd Bourcier
- Food and Drug Administration, Silver Spring, MD, United States
| | | | - Tania Cavaliero
- Swissmedic, Swiss Agency for Therapeutic Products, Bern, Switzerland
| | - Geoffrey Ebere
- Health Canada, Pharmaceutical Drugs Directorate, Ottawa, ON, Canada
| | | | | | - Kumiko Ogawa
- National Institute of Health Sciences, Kanagawa, Japan
| | - Markku Pasanen
- Faculty of Health Sciences, School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Alisa Vespa
- Health Canada, Pharmaceutical Drugs Directorate, Ottawa, ON, Canada
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Rahmani K, Wu YC, Buck NR, Lau A, Hanlon PR. Retrospective analysis of carcinogenicity assessments within FDA-notified GRAS determinations. Hum Exp Toxicol 2024; 43:9603271241254338. [PMID: 39052968 DOI: 10.1177/09603271241254338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Frameworks have been developed to standardize the assessment of carcinogenic potential in the pharmaceutical and agrochemical industries, building upon decades of research. Carcinogenicity is also evaluated during the safety evaluation of food substances, using a comprehensive approach unique to each substance. To better understand these approaches, a retrospective assessment was conducted on the publicly available database of substances notified to the United States Food and Drug Administration (US FDA) as being Generally Recognized As Safe (GRAS). The data contained within these GRAS notifications (GRNs) were reviewed for the methods used to evaluate carcinogenic potential (genotoxicity studies, 2-year bioassays, other pre-clinical animal studies) to identify patterns that could provide an understanding of how this assessment has been conducted for different categories of food substances. While different approaches to the safety evaluation were required to adapt to the unique food substances, the data in all notifications supported the conclusion of safety. The evaluation of food substances for carcinogenic potential must consider all available data, including identifying the need for when more data must be generated to support an evaluation. Due to the complexity of substances used in food, ranging from defined chemical entities to minimally processed agricultural commodities to live microorganisms, the approach to conducting the safety evaluation of food substances must be able to adapt to the most relevant scientifically supported approach. This paper illustrates the data commonly used to support the safety of different types of food substances and proposes an approach familiar to other product sectors.
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Felter SP, Bhat VS, Botham PA, Bussard DA, Casey W, Hayes AW, Hilton GM, Magurany KA, Sauer UG, Ohanian EV. Assessing chemical carcinogenicity: hazard identification, classification, and risk assessment. Insight from a Toxicology Forum state-of-the-science workshop. Crit Rev Toxicol 2022; 51:653-694. [DOI: 10.1080/10408444.2021.2003295] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | | | | | - David A. Bussard
- U.S. Environmental Protection Agency, Office of the Science Advisor, Policy and Engagement, Washington, DC, USA
| | - Warren Casey
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - A. Wallace Hayes
- University of South Florida College of Public Health, Tampa, FL, USA
| | - Gina M. Hilton
- PETA Science Consortium International e.V., Stuttgart, Germany
| | | | | | - Edward V. Ohanian
- United States Environmental Protection Agency, Office of Water, Washington, DC, USA
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Mistry P, McInnes EF, Beevers C, Wolf D, Currie RA, Salimraj R, Parsons P. An evaluation of carcinogenicity predictors from short-term and sub chronic repeat-dose studies of agrochemicals in rats: Opportunities to refine and reduce animal use. Toxicol Lett 2021; 351:18-27. [PMID: 34364947 DOI: 10.1016/j.toxlet.2021.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/15/2021] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
The aim of this study was to examine whether short term, repeat dose, rat studies provide sufficient information about potential carcinogenicity to enable predictions about the carcinogenic potential of agrochemicals to be made earlier in compound development. This study aimed to identify any correlations between toxicity findings obtained for short term rat studies (28 day and 90 day) and neoplastic findings obtained from 24 month rat carcinogenicity studies for agrochemical compounds (18 compounds) tested in Han Wistar and Sprague Dawley rats. The macroscopic pathology, microscopic pathology, hematology, biochemistry, organ weights, estrogen receptor activation and genotoxicity results were examined. Seven out of 18 non genotoxic compounds developed tumors in treated rats in the carcinogenicity study and of these, two compounds showed no preneoplastic findings in the affected tissues (false positives). Of the remaining five true positives, correlations were noted between corneal opacity and keratitis (90 day study) as early indicators of squamous cell carcinoma and papilloma of the cornea of the eye (compound 1, a hydroxyphenylpyruvate dioxygenase inhibitor) and inflammation of the stomach and kidney (90 day study) and gastric squamous cell papilloma and squamous cell carcinoma and renal tubular adenoma and carcinoma, respectively (compound 12, a fungicide with multisite activity). Minor decreases in uterine weight and increases in estradiol hydroxylation activity at 28 days were associated with endometrial adenocarcinoma (compound 18, a mitochondrial complex II electron transport inhibitor). Early liver weight increases and hepatocellular centrilobular hypertrophy (28 day study) were associated with thyroid follicular adenomas (compound 11, a succinate dehydrogenase inhibitor) in female animals only. Hepatic centrilobular hypertrophy (28 day studies) correlated with thyroid adenomas in males in carcinogenicity studies (compound 2, a hydroxyphenylpyruvate dioxygenase inhibitor). In contrast, treatment related, nasopharynx tumors (compound 3, an elongase inhibitor) and uterine adenocarcinoma (compound 9, a succinate dehydrogenase inhibitor) could not be correlated with findings from the short term studies examined. Eleven compounds displayed preneoplastic findings with no tumors (false negatives) and there were no compounds with no preneoplastic findings and no tumors (true negatives). This work indicates the value of examining historical, short term studies for specific, nonneoplastic findings which correlate with tumors in carcinogenicity studies, which may obviate the need for further animal carcinogenicity studies.
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Affiliation(s)
- Pratibha Mistry
- The Lenz, Hornbeam Park, Harrogate, North Yorkshire, HG2 8RE, United Kingdom
| | | | - Carol Beevers
- The Lenz, Hornbeam Park, Harrogate, North Yorkshire, HG2 8RE, United Kingdom
| | - Douglas Wolf
- Syngenta, Jealotts Hill, Bracknell, Berks, RG426EY, United Kingdom
| | - Richard A Currie
- Syngenta, Jealotts Hill, Bracknell, Berks, RG426EY, United Kingdom
| | - Rejin Salimraj
- Delphic HSE Solutions Ltd, Building B, Watchmoor Park, Camberley, Surrey, GU15 3YL, United Kingdom
| | - Paul Parsons
- The Lenz, Hornbeam Park, Harrogate, North Yorkshire, HG2 8RE, United Kingdom
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5
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Liang PI, Wang CC, Cheng HJ, Wang SS, Lin YC, Lin P, Tung CW. Curation of cancer hallmark-based genes and pathways for in silico characterization of chemical carcinogenesis. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2021; 2020:5857494. [PMID: 32539087 PMCID: PMC7294774 DOI: 10.1093/database/baaa045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 05/10/2020] [Accepted: 05/19/2020] [Indexed: 01/19/2023]
Abstract
Exposure to toxic substances in the environment is one of the most important causes of cancer. However, the time-consuming process for the identification and characterization of carcinogens is not applicable to a huge amount of testing chemicals. The data gaps make the carcinogenic risk uncontrollable. An efficient and effective way of prioritizing chemicals of carcinogenic concern with interpretable mechanism information is highly desirable. This study presents a curation work for genes and pathways associated with 11 hallmarks of cancer (HOCs) reported by the Halifax Project. To demonstrate the usefulness of the curated HOC data, the interacting HOC genes and affected HOC pathways of chemicals of the three carcinogen lists from IARC, NTP and EPA were analyzed using the in silico toxicogenomics ChemDIS system. Results showed that a higher number of affected HOCs were observed for known carcinogens than the other chemicals. The curated HOC data is expected to be useful for prioritizing chemicals of carcinogenic concern. Database URL: The HOC database is available at https://github.com/hocdb-KMU-TMU/hocdb and the website of Database journal as Supplementary Data.
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Affiliation(s)
- Peir-In Liang
- Phd Program in Toxicology, Kaohsiung Medical University, 100 Shiquan 1st Road, Kaohsiung 80706, Taiwan.,Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, 100 Ziyou 1st Road, Kaohsiung 80706, Taiwan
| | - Chia-Chi Wang
- Department and Graduate Institute of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, 1 Section 4 Roosevelt Rd, Taipei 10617, Taiwan
| | - Hsien-Jen Cheng
- National Institute of Environmental Health Sciences, National Health Research Institutes, 35 Keyan Road, Miaoli County 35053, Taiwan
| | - Shan-Shan Wang
- Graduate Institute of Data Science, College of Management, Taipei Medical University, 250 Wuxing Street, Taipei 10675, Taiwan
| | - Ying-Chi Lin
- Phd Program in Toxicology, Kaohsiung Medical University, 100 Shiquan 1st Road, Kaohsiung 80706, Taiwan.,School of Pharmacy, Kaohsiung Medical University, 100 Shiquan 1st Road, Kaohsiung 80706, Taiwan
| | - Pinpin Lin
- National Institute of Environmental Health Sciences, National Health Research Institutes, 35 Keyan Road, Miaoli County 35053, Taiwan
| | - Chun-Wei Tung
- National Institute of Environmental Health Sciences, National Health Research Institutes, 35 Keyan Road, Miaoli County 35053, Taiwan.,Graduate Institute of Data Science, College of Management, Taipei Medical University, 250 Wuxing Street, Taipei 10675, Taiwan
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6
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Batke M, Afrapoli FM, Kellner R, Rathman JF, Yang C, Cronin MTD, Escher SE. Threshold of Toxicological Concern—An Update for Non-Genotoxic Carcinogens. FRONTIERS IN TOXICOLOGY 2021; 3:688321. [PMID: 35295144 PMCID: PMC8915827 DOI: 10.3389/ftox.2021.688321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/25/2021] [Indexed: 11/22/2022] Open
Abstract
The Threshold of Toxicological Concern (TTC) concept can be applied to organic compounds with the known chemical structure to derive a threshold for exposure, below which a toxic effect on human health by the compound is not expected. The TTC concept distinguishes between carcinogens that may act as genotoxic and non-genotoxic compounds. A positive prediction of a genotoxic mode of action, either by structural alerts or experimental data, leads to the application of the threshold value for genotoxic compounds. Non-genotoxic substances are assigned to the TTC value of their respective Cramer class, even though it is recognized that they could test positive in a rodent cancer bioassay. This study investigated the applicability of the Cramer classes specifically to provide adequate protection for non-genotoxic carcinogens. For this purpose, benchmark dose levels based on tumor incidence were compared with no observed effect levels (NOELs) derived from non-, pre- or neoplastic lesions. One key aspect was the categorization of compounds as non-genotoxic carcinogens. The recently finished CEFIC LRI project B18 classified the carcinogens of the Carcinogenicity Potency DataBase (CPDB) as either non-genotoxic or genotoxic compounds based on experimental or in silico data. A detailed consistency check resulted in a dataset of 137 non-genotoxic organic compounds. For these 137 compounds, NOEL values were derived from high quality animal studies with oral exposure and chronic duration using well-known repositories, such as RepDose, ToxRef, and COSMOS DB. Further, an effective tumor dose (ETD10) was calculated and compared with the lower confidence limit on benchmark dose levels (BMDL10) derived by model averaging. Comparative analysis of NOEL/EDT10/BMDL10 values showed that potentially bioaccumulative compounds in humans, as well as steroids, which both belong to the exclusion categories, occur predominantly in the region of the fifth percentiles of the distributions. Excluding these 25 compounds resulted in significantly higher but comparable fifth percentile chronic NOEL and BMDL10 values, while the fifth percentile EDT10 value was slightly higher but not statistically significant. The comparison of the obtained distributions of NOELs with the existing Cramer classes and their derived TTC values supports the application of Cramer class thresholds to all non-genotoxic compounds, such as non-genotoxic carcinogens.
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Affiliation(s)
- Monika Batke
- Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Hannover, Germany
| | | | - Rupert Kellner
- Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Hannover, Germany
| | - James F. Rathman
- Altamira, LLC, Columbus, OH, United States
- Molecular Networks GmbH, Nuremberg, Germany
| | - Chihae Yang
- Altamira, LLC, Columbus, OH, United States
- Molecular Networks GmbH, Nuremberg, Germany
| | - Mark T. D. Cronin
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Sylvia E. Escher
- Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Hannover, Germany
- *Correspondence: Sylvia E. Escher
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7
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Garnick L, Gillie C, Kozal J, Monnot A, Spencer P, Quinn J, Maier A. Hazard characterization of carcinogenicity, mutagenicity, and reproductive toxicity for short chain primary nitroalkanes. J Appl Toxicol 2021; 41:1910-1936. [PMID: 33847381 DOI: 10.1002/jat.4169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/12/2021] [Accepted: 03/15/2021] [Indexed: 11/11/2022]
Abstract
Nitroalkanes are organic aliphatic hydrocarbon compounds with a nitro moiety that are commonly used as solvents or intermediates to synthesize a variety of organic compounds due to their inherent reactivity. In June 2020, a harmonized classification and labeling (CLH) proposal was submitted to the European Chemicals Agency (ECHA) for the following harmonized carcinogenicity, mutagenicity, and reproductive toxicity ("CMR") classifications for nitromethane (NM), nitroethane (NE), and 1-nitropropane (1-NP): NM Carc. 1B and Repr. 1B; NE Repr. 1B; and 1-NP Repr. 2. In this assessment, a weight of evidence (WoE) evaluation of studies on animal carcinogenicity and reproductive and developmental toxicity, genotoxicity, and mode of action for these three nitroalkanes was performed to critically assess the relevance of the proposed CMR classifications. Overall, the WoE indicates that NM, NE, and 1-NP are not carcinogenic, genotoxic, nor selective reproductive or developmental toxicants. Based on our analysis, classifying NM, NE, and 1-NP as Category 2 reproductive toxicants is most appropriate. Furthermore, not classifying NE and 1-NP with respect to their carcinogenicity is appropriate based on the available studies for this endpoint coupled with negative results in genotoxicity studies, metabolism data, and in silico predictions. We determined that the classification for NM of Carc. 1B is not appropriate, based on the fact that rat mammary and harderian tumors are likely not relevant to humans and lung and liver tumors reported in mice were equivocal in their dose-response and statistical significance.
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Affiliation(s)
| | | | | | - Andy Monnot
- Cardno ChemRisk, Cardno, San Francisco, CA, USA
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8
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Felter SP, Boobis AR, Botham PA, Brousse A, Greim H, Hollnagel HM, Sauer UG. Hazard identification, classification, and risk assessment of carcinogens: too much or too little? - Report of an ECETOC workshop. Crit Rev Toxicol 2020; 50:72-95. [PMID: 32133908 DOI: 10.1080/10408444.2020.1727843] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) organized a workshop "Hazard Identification, Classification and Risk Assessment of Carcinogens: Too Much or Too Little?" to explore the scientific limitations of the current binary carcinogenicity classification scheme that classifies substances as either carcinogenic or not. Classification is often based upon the rodent 2-year bioassay, which has scientific limitations and is not necessary to predict whether substances are likely human carcinogens. By contrast, tiered testing strategies founded on new approach methodologies (NAMs) followed by subchronic toxicity testing, as necessary, are useful to determine if a substance is likely carcinogenic, by which mode-of-action effects would occur and, for non-genotoxic carcinogens, the dose levels below which the key events leading to carcinogenicity are not affected. Importantly, the objective is not for NAMs to mimic high-dose effects recorded in vivo, as these are not relevant to human risk assessment. Carcinogenicity testing at the "maximum tolerated dose" does not reflect human exposure conditions, but causes major disturbances of homeostasis, which are very unlikely to occur at relevant human exposure levels. The evaluation of findings should consider biological relevance and not just statistical significance. Using this approach, safe exposures to non-genotoxic substances can be established.
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Affiliation(s)
| | | | | | - Alice Brousse
- European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC), Brussels, Belgium
| | | | | | - Ursula G Sauer
- Scientific Consultancy - Animal Welfare, Neubiberg, Germany
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9
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Leenaars CHC, Kouwenaar C, Stafleu FR, Bleich A, Ritskes-Hoitinga M, De Vries RBM, Meijboom FLB. Animal to human translation: a systematic scoping review of reported concordance rates. J Transl Med 2019; 17:223. [PMID: 31307492 PMCID: PMC6631915 DOI: 10.1186/s12967-019-1976-2] [Citation(s) in RCA: 151] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/08/2019] [Indexed: 12/14/2022] Open
Abstract
Background Drug development is currently hampered by high attrition rates; many developed treatments fail during clinical testing. Part of the attrition may be due to low animal-to-human translational success rates; so-called “translational failure”. As far as we know, no systematic overview of published translational success rates exists. Systematic scoping review The following research question was examined: “What is the observed range of the animal-to-human translational success (and failure) rates within the currently available empirical evidence?”. We searched PubMed and Embase on 16 October 2017. We included reviews and all other types of “umbrella”-studies of meta-data quantitatively comparing the translational results of studies including at least two species with one being human. We supplemented our database searches with additional strategies. All abstracts and full-text papers were screened by two independent reviewers. Our scoping review comprises 121 references, with various units of measurement: compound or intervention (k = 104), study/experiment (k = 10), and symptom or event (k = 7). Diagnostic statistics corresponded with binary and continuous definitions of successful translation. Binary definitions comprise percentages below twofold error, percentages accurately predicted, and predictive values. Quantitative definitions comprise correlation/regression (r2) and meta-analyses (percentage overlap of 95% confidence intervals). Translational success rates ranged from 0 to 100%. Conclusion The wide range of translational success rates observed in our study might indicate that translational success is unpredictable; i.e. it might be unclear upfront if the results of primary animal studies will contribute to translational knowledge. However, the risk of bias of the included studies was high, and much of the included evidence is old, while newer models have become available. Therefore, the reliability of the cumulative evidence from current papers on this topic is insufficient. Further in-depth “umbrella”-studies of translational success rates are still warranted. These are needed to evaluate the probabilistic evidence for predictivity of animal studies for the human situation more reliably, and to determine which factors affect this process.
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Affiliation(s)
- Cathalijn H C Leenaars
- Department of Animals in Science and Society, Faculty of Veterinary Sciences, Utrecht University, Utrecht, The Netherlands. .,Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany. .,SYRCLE, Department for Health Evidence (section HTA), Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Carien Kouwenaar
- Department of Animals in Science and Society, Faculty of Veterinary Sciences, Utrecht University, Utrecht, The Netherlands
| | - Frans R Stafleu
- Department of Animals in Science and Society, Faculty of Veterinary Sciences, Utrecht University, Utrecht, The Netherlands
| | - André Bleich
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Merel Ritskes-Hoitinga
- SYRCLE, Department for Health Evidence (section HTA), Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob B M De Vries
- SYRCLE, Department for Health Evidence (section HTA), Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Franck L B Meijboom
- Department of Animals in Science and Society, Faculty of Veterinary Sciences, Utrecht University, Utrecht, The Netherlands
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Goodman JI. Goodbye to the bioassay. Toxicol Res (Camb) 2018; 7:558-564. [PMID: 30090606 PMCID: PMC6062362 DOI: 10.1039/c8tx00004b] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 01/31/2018] [Indexed: 12/30/2022] Open
Abstract
It is time to say goodbye to the standard two-year rodent bioassay. While a few, primarily genotoxic, compounds which are clearly associated with human cancer test positive in the bioassay, there is no science-based, sound foundation for presuming it provides either a valid broad (across different chemicals) capability for discerning potential human carcinogens or a valid starting point for making human risk assessment decisions. The two basic assumptions underlying the bioassay are: (1) rodent carcinogens are human carcinogens; and (2) results obtained at high doses are indicative of results that will occur at lower, environmentally relevant, doses. Both of these assumptions are not correct. Furthermore, a reevaluation of National Toxicology Program bioassay data has revealed that if the dose group size were increased from 50 to 200 rodents per group the number of bioassays deemed to be positive would increase from approximately 50% to very close to 100%. Thus, under the extreme conditions of the bioassay (e.g., high doses, lifetime exposure and, at times, a non-physiological route of administration) virtually all chemicals tested could be made into rodent carcinogens. In recent years there have been a number of proposals to move away from the standard bioassay. In particular, a recently formulated decision tree (Cohen, 2017), which places an emphasis on dose-response relationships and invites the use of MOA information, provides a sound basis for moving on from the bioassay and towards a rational approach to both identify chemicals which appear to have the potential to cause cancer in humans and take dose-response relationships into consideration in order to place the extent, if any, of the risk they might pose into proper perspective.
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Affiliation(s)
- Jay I Goodman
- Department of Pharmacology and Toxicology , Michigan State University , East Lansing , MI 48824 , USA . ; Tel: +1-517-353-9346
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11
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Solano MDLM, Rocha NS, Barbisan LF, Franchi CADS, Spinardi-Barbisan ALT, de Oliveira MLCS, Salvadori DMF, Ribeiro LR, de Camargo JLV. Alternative Multiorgan Initiation–Promotion Assay for Chemical Carcinogenesis in the Wistar Rat. Toxicol Pathol 2016; 44:1146-1159. [DOI: 10.1177/0192623316678931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The medium-term multiorgan initiation–promotion chemical bioassay (diethylnitrosamine, methyl-nitrosourea, butyl-hydroxybutylnitrosamine, dihydroxypropylnitrosamine, dimethylhydrazine [DMBDD]) with the Fischer 344 rat was proposed as an alternative to the conventional 2-year carcinogenesis bioassay for regulatory purposes. The acronym DMBDD stands for the names of five genotoxic agents used for initiation of multiorgan carcinogenesis. The Brazilian Agency for the Environment officially recognized a variation of this assay (DMBDDb) as a valid method to assess the carcinogenic potential of agrochemicals. Different from the original protocol, this DMBDDb is 30-week long, uses Wistar rats and two positive control groups exposed to carcinogenesis promoters sodium phenobarbital (PB) or 2-acetylaminofluorene (2-AAF). This report presents the experience of an academic laboratory with the DMBDDb assay and contributes to the establishment of this alternative DMBDD bioassay in a different rat strain. Frequent lesions observed in positive groups to evaluate the promoting potential of pesticides and the immunohistochemical expressions of liver cytochrome P450 (CYP) 2B1/2B2 and CYP1A2 enzymes were assessed. Commonly affected organs were liver, kidney, intestines, urinary bladder, and thyroid. PB promoting activity was less evident than that of 2-AAF, especially in males. This study provides a repository of characteristic lesions occurring in positive control animals submitted to a modified alternative 2-stage multiorgan protocol for carcinogenesis in Wistar rat.
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Affiliation(s)
| | - Noeme Souza Rocha
- Department of Clinical Medicine, Faculty of Veterinary Medicine and Zootechnology, UNESP—São Paulo State University, Botucatu, São Paulo, Brazil
| | - Luis Fernando Barbisan
- Department of Morphology, Bioscience Institute, UNESP—São Paulo State University, Botucatu, São Paulo, Brazil
| | | | | | | | | | - Lúcia Regina Ribeiro
- Department of Pathology, Botucatu Medical School, UNESP—São Paulo State University, Botucatu, São Paulo, Brazil
| | - João Lauro Viana de Camargo
- Department of Pathology, Botucatu Medical School, UNESP—São Paulo State University, Botucatu, São Paulo, Brazil
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12
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van der Laan JW, Buitenhuis WHW, Wagenaar L, Soffers AEMF, van Someren EP, Krul CAM, Woutersen RA. Prediction of the Carcinogenic Potential of Human Pharmaceuticals Using Repeated Dose Toxicity Data and Their Pharmacological Properties. Front Med (Lausanne) 2016; 3:45. [PMID: 27790617 PMCID: PMC5063850 DOI: 10.3389/fmed.2016.00045] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/20/2016] [Indexed: 01/06/2023] Open
Abstract
In an exercise designed to reduce animal use, we analyzed the results of rat subchronic toxicity studies from 289 pharmaceutical compounds with the aim to predict the tumor outcome of carcinogenicity studies in this species. The results were obtained from the assessment reports available at the Medicines Evaluation Board of the Netherlands for 289 pharmaceutical compounds that had been shown to be non-genotoxic. One hundred forty-three of the 239 compounds not inducing putative preneoplastic lesions in the subchronic study did not induce tumors in the carcinogenicity study [true negatives (TNs)], whereas 96 compounds were categorized as false negatives (FNs) because tumors were observed in the carcinogenicity study. Of the remaining 50 compounds, 31 showed preneoplastic lesions in the subchronic study and tumors in the carcinogenicity study [true positives (TPs)], and 19 only showed preneoplastic lesions in subchronic studies but no tumors in the carcinogenicity study [false positives (FPs)]. In addition, we then re-assessed the prediction of the tumor outcome by integrating the pharmacological properties of these compounds. These pharmacological properties were evaluated with respect to the presence or absence of a direct or indirect proliferative action. We found support for the absence of cellular proliferation for 204 compounds (TN). For 67 compounds, the presence of cellular hyperplasia as evidence for proliferative action could be found (TP). Therefore, this approach resulted in an ability to predict non-carcinogens at a success rate of 92% and the ability to detect carcinogens at 98%. The combined evaluation of pharmacological and histopathological endpoints eventually led to only 18 unknown outcomes (17 categorized as FN and 1 as FP), thereby enhancing both the negative and positive predictivity of an evaluation based upon histopathological evaluation only. The data show the added value of a consideration of the pharmacological properties of compounds in relation to potential class effects, both in the negative and positive direction. A high negative and a high positive predictivity will both result in waiving the need for conducting 2-year rat carcinogenicity studies, if this is accepted by Regulatory Authorities, which will save large numbers of animals and reduce drug development costs and time.
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Affiliation(s)
- Jan Willem van der Laan
- Medicines Evaluation Board, Utrecht, Netherlands
- Division of Toxicology, Leiden Academic Center for Drug Research, Leiden, Netherlands
| | | | | | - Ans E. M. F. Soffers
- Division of Toxicology, Wageningen University and Research Centre, Wageningen, Netherlands
| | | | | | - Ruud A. Woutersen
- Division of Toxicology, Wageningen University and Research Centre, Wageningen, Netherlands
- TNO Innovation for Life, Zeist, Netherlands
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