Achieving scientific and regulatory success in implementing non-animal approaches to human and veterinary rabies vaccine testing: A NICEATM and IABS workshop report

Animal testing for vaccines. Implementing replacement, reduction and refinement: challenges and priorities

“…Jean-Michel Chapsal, from the European Partnership for Animal Alternative Approaches to Animal Testing (EPAA), made an overview of the current status of the validation of an ELISA for potency assay of human rabies vaccines within the Biological Standardisation Programme 148 (BSP148). Summarizing the current potency testing method, the NIH method, he noted its several criticalities (including a very high variability, and the safety factor of requiring use of a live virus [ 30 ]), and the extreme severity of the procedure's effects on the animals, to highlight the consensus on the need to find a suitable in vitro alternative, and then proceeded to trace back the steps that led to the current BSP148 project for the validation of a G-protein ELISA for potency testing [ 31 ]. He mentioned the 2012 EPAA workshop at Arcachon (France), where the decision to create an International Working Group for the creation of an G-protein ELISA replacement to NIH test was taken, to be based on the evaluation of three competing ELISA assays, a study which eventually produced a candidate ELISA (developed at Sanofi Pasteur) based on 2 monoclonal antibodies (accessible to all laboratories, and commercially available worldwide from two suppliers) specific to the conformational trimeric form of the glycoprotein G, which does not react with non-immunogenic soluble glycoprotein, that recognizes most rabies strains used worldwide for human vaccines, and is able to discriminate sub-potent vaccines altered by a variety of methods including over-inactivation by b-propiolactone, the viral inactivation agent.…”

“…Richard Hill (International Alliance for Biological Standardization (IABS), U.S.A) commented on the need to encourage a change in the regulators' approach, which is often strongly favoring a conservative perspective based on old codified methodologies. As an example of the possible complexities involved in transitioning away from in vivo testing, Hill brought up the complex case of veterinary rabies vaccines [ 31 ] – a multi-species product that is tested and licensed separately for many species, each of which needs to be tested to validate efficacy. Veterinary vaccines comprise over 200 different antigens which are available in many combinations.…”

Overcoming scientific barriers in the transition fromin vivoto non-animal batch testing of human and veterinary vaccines

“…These antigen quantification methods may be physiochemical or immunochemical assays that are specific for one or more dominant antigens of the vaccines. In particular, the development of enzyme-linked immunosorbent assays (ELISAs) for antigen quantification has been successful for the replacement of in vivo potency tests of several vaccines in Europe, including those against Newcastle disease in poultry, foot-and-mouth disease in cattle, leptospirosis in cattle and dogs (monographs 0447 and 1939), rabies in both animals and humans, and hepatitis A and B in humans (Figure 1a) [17,20,[26][27][28][29]. Other ELISAs for antigen quantification have shown to be successful in determining the potency of some but not all inactivated vaccines and toxoid vaccines, but these are not yet fully validated and/or approved by the regulatory authorities in Europe.…”