Drug development for rare diseases is faced with the dilemma of a small number of patients, scarcity of research samples, and high difficulty of clinical trials. One of the major problems hindering drug development for rare diseases is the lack of suitable animal models in preclinical studies. The establishment and availability of stable and reliable animal models of rare diseases are irreplaceable for the study of rare diseases. They have an inestimable potential for the study of rare disease pathogenesis, drug target research, and therapeutic effects evaluation. Several excellent models have already been developed, such as the GAA-knockout mouse model for Pompe's disease and the Sgca-null mouse model for α-sarcoglycanopathy. Some of these have already led to the development of much-needed therapies such as ERTs. Nevertheless, there is a continuing need to develop more effective models to facilitate drug development and clinical trial design for rare diseases.

Fig. 1 Animal models presented to the EMA Committee for Orphan Medicinal Products. (Vaquer G, et al., 2013)