Other animals, such as mice, rats, rabbits, dogs and monkeys, are widely used as surrogates for humans in fundamental medical research. This involves creating disorders in animals by chemical, surgical or genetic means, with the aim of mimicking selected aspects of human illnesses.
It is a truism that any model or surrogate is not identical to the target being modelled. So, in medical research, experiments using animals or cell cultures or even healthy volunteers instead of patients (being the target population with the target illness) will inevitably have limitations, although these will be greater or lesser depending on the model.
Langley, G. (2009). The validity of animal experiments in medical research. RSDA, 1, 161-8.