The use of integrated and intelligent testing strategies in the prediction of toxic hazard and in risk assessment.

There is increasing concern that insurmountable differences between humans and laboratory animals limit the relevance and reliability for hazard identification and risk assessment purposes of animal data produced by traditional toxicity test procedures. A way forward is offered by the emerging new technologies, which can be directly applied to human material or even to human beings themselves. This promises to revolutionise the evaluation of the safety of chemicals and chemical products of various kinds and, in particular, pharmaceuticals. The available and developing technologies are summarised and it is emphasised that they will need to be used selectively, in integrated and intelligent testing strategies, which, in addition to being scientifically sound, must be manageable and affordable. Examples are given of proposed testing strategies for general chemicals, cosmetic ingredients, candidate pharmaceuticals, inhaled substances, nanoparticles and neurotoxicity.

In vivo research using early life stage models.

Scientists, for a variety of reasons, need to carry out in vivo research. Since experiments that require the use of adult animals pose various logistical, economical and ethical issues, the use of embryonic and larval forms of some organisms are potentially attractive alternatives. Early life stages are appealing because, in general, large numbers of individuals can be maintained in relatively simple housing, minimising costs, and their use involves fewer legal formalities. With this succinct review, we aim to provide an overview of different biological issues that have been successfully explored with the help of eggs, embryos and larvae from the frog, zebrafish and chicken.

Immunotoxicity and immunogenicity of biopharmaceuticals: design concepts and safety assessment.

The biopharmaceutical market has grown steadily since the early 1980s and today over 150 protein biopharmaceuticals have been approved for clinical use. These products often exhibit forms of immunotoxicity that often only come to light during clinical studies. The predictive value of animal studies and traditional in vitro screens is questionable, with few existing methods able to predict immunotoxicity in a way that is useful for estimating risk for entire patient populations for a specific, and often unique, product. Here, the relative merits of rational design and alternative strategies for immunotoxicity testing are considered with reference to the outcomes of preclinical and clinical studies on biopharmaceuticals. Specific reference is made to the prediction of immunogenicity using organotypic models, transgenic models of autoimmunity and immunogenicity as well as rodent models of hypersensitivity, immunosuppression and immunostimulation. The role played by human cell-based assays and in silico prediction models that have been developed and validated for the assessment of chemical classes is also appraised.

Welfare implications of standardised protocols for phenotyping and genotyping genetically altered mice.

Phenotype-driven mouse mutagenesis programmes are widely advocated as a means of assigning functions to human genes. These programmes often give rise to a number of animal welfare concerns, not least the large numbers of animals that are used. Here, we consider how the phenotyping screens used in all such programmes can be improved, with specific reference to the standard phenotyping procedures described by the European Mouse Phenotyping Resource of Standardised Screens (EMPReSS). Although we commend the efforts of the Consortium in developing standardised screens for phenotyping, animal welfare should take precedence over technical ease and the cost implications of the research. A number of recommendations are made that could reduce the suffering of the mice used in such studies. These include the use of minimally invasive practices, reduced sample sizes, and combining the assays used in such studies.

Translation of new technologies: from basic research to drug discovery and development.

Despite increasing investment in drug discovery and development, only around one in every ten new medicinal products that progresses to clinical testing ever reach from the registration stage. Approximately half of all drug failures are attributed to problems with efficacy and toxicity not anticipated from preclinical studies. As a consequence, the pharmaceutical industry is adopting a much more flexible and multi-disciplinary approach to drug discovery and development. Indeed, the line between basic and applied science is constantly being eroded, not least because of the increasing sophistication of therapeutic procedures and the complexity of the diseases that they aim to treat. Here, we look at the new technologies that are being explored as a way of reducing drug attrition rates and the development of chemical drugs and biotherapeutics. Specifically, we will consider the ways in which genomics and related disciplines, engineered cell-based and microfluidics systems, and nanotechnologies are being developed and used alongside in silico platforms during early drug pharmacokinetics and toxicity studies. The way in which information from such systems biology-oriented approaches can be integrated with information from animal based preclinical safety, toxicological and pharmacological studies on investigative medicinal products is considered, in view of its current and possible impact on clinical trial design.

The use of human cell line reporter gene-based assays in chemical toxicity testing.

Genetically modified rodents allow greater sensitivity in monitoring DNA damage or gene expression than traditional rodent bioassays and have become increasingly used for toxicity testing, particularly with the greater availability of protein and DNA-based toxicity biomarkers. Here, the advantages and limitations of several in vitro reporter assays already used to study the mechanisms of toxicity are discussed in relation to the in vivo traditional and reporter-based bioassays for carcinogenicity, mutagenicity, endocrine changes and inflammation endpoints to examine the scope for refining and replacing transgenic in vivo models.

The UK Food Standards Agency draft report on variability and uncertainty in toxicology: a response by FRAME.

At the request of the Food Standards Agency, the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) established a Working Group on Variation and Uncertainty in Toxicology (WG VUT). In April 2006, the WG VUT produced a draft report for public consultation. FRAME made a submission in response to this consultation in July 2006. We commend the WG VUT for its comprehensive account of many of the problems associated with risk assessment, and for making recommendations about the problems that need to be addressed. We were particularly encouraged by the WG VUTs recognition of the need for guidelines on how toxicological studies should be conducted and data analysed. However, we believe that the report has not achieved all of its objectives. It does not adequately consider how modern technologies, experimental design, statistical analysis and species extrapolation can be used in practice to address variability and uncertainty. There is a disproportionate focus on the sources of variability and uncertainty in human data, with relatively little consideration of how variation and uncertainty due to animal tests can be addressed. Furthermore, it is clear that, until the advantages and limitations of all toxicological methods are fully appraised and testing strategies and guidelines are agreed, the scope for improving the existing approaches to risk assessment will be severely limited. Hence, the use of alternative methods for hazard identification and characterisation merit more consideration than they were given in the draft report.

The relevance of genetically altered mouse models of human disease.

The impetus to develop useful models of human disease and toxicity has resulted in a number of large-scale mouse mutagenesis programmes. This, in turn, has stimulated considerable concern regarding the scientific validity and welfare of genetically altered mice, and the large numbers of mice that are required by such programmes. In this paper, the scientific advantages and limitations of genetically altered mice as models of several human diseases are discussed. We conclude that, while the use of some such mouse models has contributed considerably to an understanding of human disease and toxicity, other genetically altered mouse models have limited scientific relevance, and fewer have positively contributed to the development of novel human medicines. Suggestions for improving this unsatisfactory situation are made.

An update on TGN1412.

In the last issue of ATLA, we assessed whether the existing methods for assessing the safety and efficacy of new candidate medicines was adequate for the testing of humanised therapeutic agents. We made specific reference to the failed TGN1412 first-in-man study that took place earlier this year. This paper was circulated to experts and those involved in the development or testing of TGN1412. More recently, the Focus on Alternatives group has made a submission to the Expert Working Group that is currently considering how such incidences can be avoided in the future. Here, we provide an update of the events relating to the TGN1412 clinical trial.

TGN1412: time to change the paradigm for the testing of new pharmaceuticals.

Clinical studies in human volunteers are an essential part of drug development. These studies are designed to account for possible differences between the effects of pharmaceutical products in preclinical studies and in humans. However, the tragic outcome of the recent Phase 1 clinical trial on TGN1412 casts considerable doubt over the relevance of this traditional drug development paradigm to the testing of therapeutic agents for human use. The role of alternatives to animal testing is considered, and a series of recommendations are made, which could ensure that clinical trials are well informed and based on the most relevant scientific information.

An analysis of the Home Office Statistics of Scientific Procedures on Living Animals, Great Britain 2004.

The 2004 Statistics of Scientific Procedures on Living Animals were released by the Home Office in December 2005. They indicate that, for the third year running, there has been a significant increase in the number of laboratory animal procedures undertaken in Great Britain, and that increasing numbers of animals are involved. The overall trends in the use of toxicological and non-toxicological procedures involving animals are described. Particular emphasis is placed on the production and use of genetically modified animals, the production of biological materials, and acute toxicity testing. The use of non-human primates and dogs is also discussed. The implications of these latest statistics are considered with reference to the implementation of the Three Rs and their consequences for animal welfare.