Non-human primates in biomedical research : reasons and alternatives for their use

Abstract

More than one hundred thousand non-human primates are used for biomedical research annually worldwide. While the use of these animals leads to ethical objections, the scientific quality of primate studies is also the subject of discussion. This study investigates the extent to which the use of primates could be reduced or replaced through an analysis of the existing literature and interviews with stakeholders. In fundamental studies on disease, different (animal) models are often used alongside each other; arguments regarding why primates are used are only seldom given. Primates mainly seem to be used for immunologic reasons, which exclude the use of any in vitro alternative. In preclinical research, it appears that primates are mainly used for conventional medicines, which is contradictory to expectations. Next to scientific arguments for the use of primates, non-scientific reasons also play a major role. Financial and regulatory issues appear to be the most important factors, which hamper the replacement or reduction of primate use. The necessity of using primates for routine safety tests has not been established. The use of primates for both fundamental and preclinical studies is likely to increase in the near future, consequently increasing the need to replace or reduce the use of primates as much as possible. The most promising alternatives seem to be the use of other animal species, human tissue or volunteers and a tiered approach to reduce the number of primates. Although the use of other animal models is certainly not a 3R-alternative, this is generally regarded as some improvement and a first step towards complete replacement. However, there are a number of factors that hamper the development and implementation of alternatives. These include problems with the selection of the relevant animal model, regulatory requirements, information, motivation and funding for alternatives, as well as personal and commercial interests. Furthermore, there are no criteria that a model has to fullfil, which makes it hard to judge the traditional model or an alternative method on its merits. This, together with safety issues and fear of liability, makes regulators slow to implement alternatives. In view of this, the most relevant model for both fundamental and applied studies should be subject to discussion. For primate studies, advice on the relevance of the model could even be mandatory. Furthermore, the criteria that any model should fulfil must be decided and research into alternatives should be intensified. However, any stricter regulations on the use of primates should only be decided on in discussion with stakeholders, to prevent the outsourcing of primate studies to countries where animal welfare may be poorer.