A new group housing approach for non-human primate metabolism studies

Understanding the absorption, distribution, metabolism and excretion (ADME) of candidate drugs in preclinical species is an integral part of the safety and efficacy evaluation in drug development. For this purpose, the housing of single animals in metabolism cages has historically been common practice for ADME studies. Whilst mini-pigs and dogs are selected wherever possible, non-human primates (NHPs) are used where there is no suitable scientific alternative. Having undergone only minimal revisions over the past 30 years, the traditional single-housing metabolism cage design for NHPs significantly limits normal vertical movement and social behaviours in primates. Minimising animal suffering and improving welfare is an important aspect of working with animals in research and Novo Nordisk A/S, together with collaborators, has focused on this area for many years. A novel metabolism cage for group housing of NHPs has been designed in a joint collaboration between Novo Nordisk A/S and Covance Inc. The advantages of this novel cage are extensive, including a significantly increased cage volume and ability for socialisation, as well as improvements to alleviate stress and boredom. The excretion balance data from six male NHPs housed in single or group metabolism cages were compared using the radiolabelled test compound [¹⁴C]-quetiapine. Welfare, in terms of stress and behaviour, when animals were single or group housed was also assessed. Mean recoveries of radioactivity were shown to be comparable irrespective of housing design (83.2% for group-housed animals vs. 87.1% for single-housed animals), supporting the potential suitability of NHP group housing for future metabolism ADME studies.