“The cynomolgus monkey was chosen as the relevant responder species and a comprehensive toxicology program was conducted with single- and multiple-dose studies up to duration of 6 months to characterize the overall safety of tocilizumab.”
Cross-reacts with monkey IL-6R in vitro and in vivo; no binding to rat, mouse or rabbit IL-6R
“The cynomolgus monkey was chosen as the pharmacologically relevant species because tocilizumab cross-reacts with monkey IL-6R under in vitro and in vivo conditions.”