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The implementation of the 3Rs (replacement, reduction and refinement) is emphasized in EU Directive 2010/63. The task of the animal welfare bodies (AWB) is to strengthen animal welfare and develop the 3Rs at research animal facilities. In 2016, we surveyed the knowledge on, attitudes towards and implementation of the 3Rs within AWBs at eight major Swedish universities. Based on responses of 34 closed-ended questions from 44 of 90 AWB members, the overall attitude towards the 3Rs was positive. AWB members did not believe that the 3Rs slow down innovation or result in increased costs, and refinement was considered beneficial for research quality. AWB members were particularly positive towards refinement questions in the survey. A majority of the AWB members predicted that alternative methods will never replace animal use. Researchers as a group represented in the AWBs were significantly less positive towards the 3Rs compared to the group of veterinarians. The tasks of the AWBs, e.g., giving advice on the 3Rs and following up on animal use in projects, were often not carried out in the AWB or not known by the respondents. Our results indicate a need for more practical and regulatory guidance and support to the AWBs. To reach the goal of the EU Directive to phase out animal use in research and education, we suggest that technical expertise in replacement techniques is included in the AWBs. We emphasize the need to strengthen the awareness of the 3Rs among researchers at Swedish universities.

Animal testing for toxicity assessment of chemicals and pharmaceuticals must take the 3R principles into consideration. During toxicity testing in vivo, clinical signs are used to monitor animal welfare and to inform about potential toxicity. This study investigated possible associations between clinical signs, body weight change and histopathological findings observed after necropsy. We hypothesized that clinical signs and body weight loss observed during experiments could be used as early markers of organ toxicity. This represents a potential for refinement in terms of improved study man­agement and decreasing of pain and distress experienced during animal experiments. Data from three sequential toxicity studies of an anti-cancer drug candidate in rats were analyzed using the multivariate partial least squares (PLS) regression method. Associations with a predictive value over 80% were found between the occurrence of mild to severe clinical signs and histopathological findings in the thymus, testes, epididymides and bone marrow. Piloerection, eyes half shut and slightly decreased motor activity were most strongly associated with the pathological findings. A 5% body weight loss was found to be a strong empirical predictor of pathological findings but could also be predicted accurately by clinical signs. Thus, we suggest using mild clinical signs and a 5% body weight loss as toxicity markers and as a non-invasive surveillance tool to monitor research animal welfare in toxicity testing. These clinical signs may also enable reduction of animal use due to their informative potential to support scientific decisions regarding drug candidate selection, dose setting, study design, and toxicity assessment.

Reducing the number of laboratory animals used and refining experimental procedures to enhance animal welfare are fundamental questions to be considered in connection with animal experimentation. Here, we explored the use of cardinal ethical weights for clinical signs and symptoms in rodents by conducting trade-off interviews with members of Swedish Animal Ethics Committees in order to derive such weights for nine typical clinical signs of toxicity. The participants interviewed represent researchers, politically nominated political nominees and representatives of animal welfare organizations. We observed no statistically significant differences between these groups with respect to the magnitude of the ethical weights assigned, though the political nominees tended to assign lower weights. Overall, hunched posture was considered the most severe clinical sign and body weight loss the least severe. The ethical weights assigned varied considerably between individuals, from zero to infinite value, indicating discrepancies in prioritization of reduction and refinement. Cardinal ethical weights may be utilized to include both animal welfare refinement and reduction of animal use in designing as well as in retrospective assessment of animal experiments. Such weights may also be used to estimate ethical costs of animal experiments.

Hazard characterization during pharmaceutical development identifies the candidate drug's potential hazards and dose-response relationships. To date, the no-observed-adverse-effect-level (NOAEL) approach has been employed to identify the highest dose which results in no observed adverse effects. The benchmark dose (BMD) modeling approach describes potential dose-response relationships and has been used in diverse regulatory domains, but its applicability for pharmaceutical development has not previously been examined. Thus, we applied BMD-modeling to all endpoints in three sequential in vivo studies in a drug development setting, including biochemistry, hematology, organ pathology and clinical observations. In order to compare the results across such a broad range of effects, we needed to standardize the choice of the critical effect size (CES) for the different endpoints. A CES of 5%, previously suggested by the European Food Safety Authority, was compared with the study NOAEL and with the General Theory of Effect Size, which takes natural variability into account. Compared to the NOAEL approach, the BMD-modeling approach resulted in more informative estimates of the doses leading to effects. The BMD-modeling approach handled well situations where effects occurred below the lowest tested dose and the study's NOAEL, and seems advantageous to characterize the potential toxicity during safety assessment. The results imply a considerable step forward from the perspective of reducing and refining animal experiments, as more information is yielded from the same number of animals and at lower doses. Taken together, employing BMD-modeling as a substitute, or as a complement, to the NOAEL approach seems appropriate. [Display omitted] • Benchmark dose (BMD) approach was used to model multiple endpoints in drug development. • BMD improved the informative value for both dose-setting and safety evaluation. • BMD indicated effects at lower doses than the alternative NOAEL approach. • BMD implied a step towards refinement of animal experiments. • BMD can potentially improve the pharmaceutical development process. [ABSTRACT FROM AUTHOR]