The evolving role of investigative toxicology in the pharmaceutical industry.

For decades, preclinical toxicology was essentially a descriptive discipline in which treatment-related effects were carefully reported and used as a basis to calculate safety margins for drug candidates. In recent years, however, technological advances have increasingly enabled researchers to gain insights into toxicity mechanisms, supporting greater understanding of species relevance and translatability to humans, prediction of safety events, mitigation of side effects and development of safety biomarkers. Consequently, investigative (or mechanistic) toxicology has been gaining momentum and is now a key capability in the pharmaceutical industry. Here, we provide an overview of the current status of the field using case studies and discuss the potential impact of ongoing technological developments, based on a survey of investigative toxicologists from 14 European-based medium-sized to large pharmaceutical companies.

Introducing the concept of virtual control groups into preclinical toxicology testing.

Sharing legacy data from in vivo toxicity studies offers the opportunity to analyze the variability of control groups stratified for strain, age, duration of study, vehicle and other experimental conditions. Historical animal control group data may lead to a repository, which could be used to construct virtual control groups (VCGs) for toxicity studies. VCGs are an established concept in clinical trials, but the idea of replacing living beings with virtual data sets has so far not been introduced into the design of regulatory animal studies. The use of VCGs has the potential of a 25% reduction in animal use by replacing the control group animals with existing randomized data sets. Prerequisites for such an approach are the availability of large and well-structured control data sets as well as thorough statistical evaluations. the foundation of data sharing has been laid within the Innovative Medicines Initiatives projects eTOX and eTRANSAFE. For a proof of principle participating companies have started to collect control group data for subacute (4-week) GLP studies with Wistar rats (the strain preferentially used in Europe) and are characterizing these data for its variability. In a second step, the control group data will be shared among the companies and cross-company variability will be investigated. In a third step, a set of studies will be analyzed to assess whether the use of VCG data would have influenced the outcome of the study compared to the real control group.

Optimizing drug discovery by Investigative Toxicology: Current and future trends.

Investigative Toxicology describes the de-risking and mechanistic elucidation of toxicities, supporting early safety decisions in the pharmaceutical industry. Recently, Investigative Toxicology has contributed to a shift in pharmaceutical toxicology, from a descriptive to an evidence-based, mechanistic discipline. This was triggered by high costs and low throughput of Good Laboratory Practice in vivo studies, and increasing demands for adhering to the 3R (Replacement, Reduction and Refinement) principles of animal welfare. Outside the boundaries of regulatory toxicology, Investigative Toxicology has the flexibility to embrace new technologies, enhancing translational steps from in silico, in vitro to in vivo mechanistic understanding to eventually predict human response. One major goal of Investigative Toxicology is improving preclinical decisions, which coincides with the concept of animal-free safety testing. Currently, compounds under preclinical development are being discarded due to the use of inappropriate animal models. Progress in Investigative Toxicology could lead to humanized in vitro test systems and the development of medicines less reliant on animal tests. To advance this field a group of 14 European-based leaders from the pharmaceutical industry founded the Investigative Toxicology Leaders Forum (ITLF), an open, non-exclusive and pre-competitive group that shares knowledge and experience. The ITLF collaborated with the Centre for Alternatives to Animal Testing Europe (CAAT-Europe) to organize an "Investigative Toxicology Think-Tank", which aimed to enhance the interaction with experts from academia and regulatory bodies in the field. Summarizing the topics and discussion of the workshop, this article highlights Investigative Toxicology's position by identifying key challenges and perspectives.

Improving the Safety Assessment of Chemicals and Drug Candidates by the Integration of Bioinformatics and Chemoinformatics Data.

The application of read-across and in silico tools for regulatory decision-making has been limited for pharmaceutical compounds to the assessment of genotoxic impurity. In contrast, the broad availability of toxicity data for industrial chemicals has triggered regulatory frameworks for read-across (e.g. ECHA Read-Across Assessment Framework), software tools and public databases for an automated process of gap filling in the context of safety assessment. This MiniReview provides an overview of the currently existing in silico and read-across approaches for chemicals together with recent developments for pharmaceutical compounds in these areas. It also highlights the differences and commonalities in the in silico safety assessment of industrial chemicals and drug candidates. Whereas toxicity data collection and sharing is now common practice for chemicals falling under the European REACH regulation (Registration, Evaluation, Authorisation and Restriction of Chemicals), the biggest hurdle for establishing preclinical safety databases for pharmaceutical compounds is the unwillingness to share proprietary data and lack of published data sets. In a recent consortium approach, thirteen pharmaceutical companies, eleven academic partners and six small to medium size enterprises (SMEs) of the bioinformatics sector joined forces over the last 7 years within the European Innovative Medicines Initiative project eTOX ('electronic toxicity') to design and implement a strategy for leveraging these preclinical data for small molecules and sharing them across project partners. The eTOX database has evolved as the largest preclinical toxicity database for drugs and drug candidates and currently contains more than 1900 different chemical structures and more than 8000 in vivo toxicity study data sets. It can be foreseen that the development and application of such databases for drugs or drug candidates will in the future also cross-fertilize the read-across and the in silico assessment of industrial or consumer chemicals particularly as soon as human safety data from clinical trials are integrated too.

Legacy data sharing to improve drug safety assessment: the eTOX project.

The sharing of legacy preclinical safety data among pharmaceutical companies and its integration with other information sources offers unprecedented opportunities to improve the early assessment of drug safety. Here, we discuss the experience of the eTOX project, which was established through the Innovative Medicines Initiative to explore this possibility.

Investigative safety science as a competitive advantage for Pharma.

INTRODUCTION: Following a US National Academy of Sciences report in 2007 entitled "Toxicity Testing of the 21st Century: a Vision and a Strategy," significant advances within translational drug safety sciences promise to revolutionize drug discovery and development. The purpose of this review is to outline why investigative safety science is a competitive advantage for the pharmaceutical industry. AREAS COVERED: The article discusses the essential goals for modern investigative toxicologists including: cross-species target biology; molecular pathways of toxicity; and development of predictive tools, models and biomarkers that allow discovery researchers and clinicians to anticipate safety problems and plan ways to address them, earlier than ever before. Furthermore, the article emphasizes the importance of investigating unanticipated clinical safety signals through a combination of mechanistic preclinical studies and/or molecular characterization of clinical samples from affected organs. EXPERT OPINION: The traditional boundaries between pharma industry teams focusing on safety/efficacy and preclinical/clinical development are rapidly disappearing in favor of translational safety science-centric organizations with a vision of bringing more effective medicines forward safely and quickly. Comparative biology and mechanistic toxicology approaches facilitate: i) identifying translational safety biomarkers; ii) identifying new drug targets/indications; and iii) mitigating off-target toxicities. These value-adding safety science contributions will change traditional toxicologists from side-effect identifiers to drug development enablers.

Inroads to predict in vivo toxicology-an introduction to the eTOX Project.

There is a widespread awareness that the wealth of preclinical toxicity data that the pharmaceutical industry has generated in recent decades is not exploited as efficiently as it could be. Enhanced data availability for compound comparison ("read-across"), or for data mining to build predictive tools, should lead to a more efficient drug development process and contribute to the reduction of animal use (3Rs principle). In order to achieve these goals, a consortium approach, grouping numbers of relevant partners, is required. The eTOX ("electronic toxicity") consortium represents such a project and is a public-private partnership within the framework of the European Innovative Medicines Initiative (IMI). The project aims at the development of in silico prediction systems for organ and in vivo toxicity. The backbone of the project will be a database consisting of preclinical toxicity data for drug compounds or candidates extracted from previously unpublished, legacy reports from thirteen European and European operation-based pharmaceutical companies. The database will be enhanced by incorporation of publically available, high quality toxicology data. Seven academic institutes and five small-to-medium size enterprises (SMEs) contribute with their expertise in data gathering, database curation, data mining, chemoinformatics and predictive systems development. The outcome of the project will be a predictive system contributing to early potential hazard identification and risk assessment during the drug development process. The concept and strategy of the eTOX project is described here, together with current achievements and future deliverables.

Preclinical evaluation of potential nilotinib cardiotoxicity.

In vitro, concentrations ≥ 10 µM of nilotinib were needed to induce markers of cytotoxicity, apoptosis, and endoplasmic reticulum stress in both neonatal rat ventricular myocytes, a putative target tissue, and non-target heart fibroblasts, indicating a lack of cardiomyocyte-specific nilotinib toxicity in vitro. In rats, oral nilotinib treatment at 80 mg/kg for 4 weeks induced increased heart weight; however, this was not associated with relevant histopathological changes or effects on heart function. Thus, nilotinib at and above clinically relevant concentrations (4.27 µM) did not induce overt cardiovascular pathologies or heart failure in vitro or in vivo under study conditions.