Cross-reactivity studies preclinical safety evaluation

Some biotechnologically derived pharmaceuticals will cross-react with species that can be evaluated toxicologically, while others cross-react only with nonhuman primates such as the chimpanzee, a protected species. In this case, a well-designed safety, or Phase 0 study at doses higher than the proposed clinical dose may provide valuable safety information. However, a lack of cross-reactivity with any nonhuman species does not necessarily make preclinical safety evaluation impossible, not does it limit toxicity testing to species in which the protein lacks relevant pharmacological activity. Some alternative possibilities are summarized in Table 12.9. 

Omalizumab and adalimumab are examples of monoclonal antibodies, developed for chronic non-life-threatening indication, that showed cross-reactivity to cynomolgus macaques as well as to humans. This broader species cross-reactivity allowed for a more thorough preclinical safety evaluation of the human monoclonal antibody developed for human use in the cynomolgus macaque. In the case of omalizumab, fertility studies and developmental tox-icitiy studies were conducted in macaques in addition to the chronic toxicity studies. For adalimumab, no reproductive and developmental toxicity studies were conducted. The value of conducting fertility and developmental studies in macaques with monoclonal antibodies is described in Chapter 17. 

Hah W, Price-Schiavi SA, Wicks J, Rojko JL. Design and analysis of tissue cross reactivity studies. In Cavagnaro JA, ed. Preclinical Safety Evaluation of Biopharmaceuticals. New York Wiley, 2006. 

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