Preclinical methods assess the toxicity of a drug and examine its potential effects on the human body; they are conducted in-vivo (testing within the living animal) and in-vitro (testing within glass tubes, etc.). These methods are in fact required by pharmaceutical regulatory authorities to ensure that a drug is safe for human use and shows efficacy prior to beginning human clinical trials. In-vitro testing includes e.g. analysis of receptor binding, investigations regarding the mechanism of action and the chemical structure, as well as confirmation of physical and chemical properties.
Furthermore, therapeutic proteins are frequently immunogenic in animals. Immunogenicity in animal models is not very predictive for humans. However, assessment of immunogenicity in animals may be useful to interpret nonclinical toxicological and pharmacological data. In addition, immunogenicity in animal models may reveal potential antibody related toxicities that should be monitored during clinical trials.