For the batch release of vaccines on the European market, a limited number of quality tests already performed by the manufacturer need to be repeated by an OMCL (Official Medicines Control Laboratory) before a release certificate for this specific batch can be granted. In general, testing on animals is only required for pre-clinical studies in order to test the toxicity of the drug substance and not for routine batch release. However, for some biological medicinal products in general and vaccines in particular, the quality cannot fully be assessed by physicochemical testing alone and therefore tests involving laboratory animals to measure biological characteristics such as safety and potency tests are needed.Currently a large number of animals are required for testing the safety and potency of vaccines both by the manufacturer and the national control authorities. Since the eighties of last century; the European Pharmacopoeia has invested time and effort in the reduction, the replacement and the refinement of animal tests, better known as the 3R's principle.During the past twenty years, IPH has implemented several 3R principles following the Ph. Eur principles for the official batch release of a DTPa-IPV combined vaccine. For the potency testing of diphtheria and tetanus toxoid vaccines, the multiple dilution assay was replaced by a single dilution assay, based on historical data, leading to a threefold reduction in the amount of animals used. The same reduction scheme has been implemented for testing the immunogenicity of acellullar pertussis (aP) vaccines. At IPH, a further reduction in the number of laboratory animals used was obtained by limiting the potency testing on DTPa-Hepb and DTPa-IPV vaccines to the first final bulk that is formulated with a new bulk antigen instead of each final bulk. This reduction fitted in the framework of the possibility within the OCABR network, to submit a proposal in order to reduce the number of animals to be used during batch release. To test the specific toxicity in vaccines containing the whole cell pertussis component, the mouse weight gain test is used. The use of 10 mice was required by the Ph. Eur. until 2001. In edition 4.2 of the Ph. Eur. published in 2002, it was stipulated to use not fewer than 5 healthy mice instead of ten mice. Implementing this reduced number of mice per test at IPH also resulted in a substantial reduction in the use of laboratory animals. To conclude, since IPH started in 1989 with the implementation of several 3R measures, the number of animals used has been drastically reduced. For example, in the case of a DTPa-IPV combined vaccine, a 7 fold reduction of the number of animals has been achieved as compared to a simulated situation where none of the above described reductions would have been implemented. With respect to refinement, currently at IPH a validation study, in collaboration with the manufacturer, is ongoing to set a more humane endpoint for the execution of the lethal challenge potency assays for tetanus and pertussis. The ideal situation however would be the replacement of the in vivo studies by a reliable in vitro assay omitting the use of laboratory animals, but this is an even more time consuming effort.
