Current progress of research and use of microminipigs in drug development

The use of minipigs has been increasing in the areas of pharmacology researches and drug development. The microminipig developed by Fuji Micra Inc. (Shizuoka, Japan) inherits characteristics of other pig strains showing several similarities to humans in anatomy, physiology, omnivorousness and diurnal, but at the same time has several advantages over other pig strains because of its small size which allows easy keeping, handling and dosing, and saving of test substances. The microminipig weighs about 10 kg at the age of 6 months. Canine cages can be used to keep the animal. Swine leukocyte antigens (SLA) are defined in each individual animal which is useful for testing immunological reactions. As there are many similarities in metabolic enzymes and transporters to those in humans, the microminipig is a powerful animal model for toxicokinetic studies. Unfortunately as in other minipigs the microminipig is not appropriate for embryo-fetal development studies of antibody drugs due to its poor placental transfer, but can be used for other reproductive and developmental studies. Repeat dose toxicity, safety pharmacology, immunotoxicity and local tolerance studies should be also other arenas of this animal model.