Normal cynomolgus monkeys: inhibition of IL-6-stimulated CRP production and soluble IL-6R binding (vs tocilizumab)
“The pharmacology of satralizumab and tocilizumab was studied in terms of inhibitory effects on IL-6-stimulated C-reactive protein (CRP) production (i.e. on classical signaling), free and total (both free IL-6R and receptor bound to satralizumab) soluble IL-6R concentration (i.e. on trans-signaling).”
No NMOSD model established in monkeys, the only cross-reactive species
“As satralizumab showed cross-reactivity in cynomolgus monkey but not in mice or rats, in vivo pharmacology of satralizumab was studied in cynomolgus monkeys. The efficacy of satralizumab in NMOSD models in vivo have not been investigated since no NMOSD model has been established in monkeys.”
EMA: CRP and soluble IL-6R are non-specific biomarkers and no disease model was studied; further mechanistic clarification required
“However, given that CRP and free soluble IL-6R are both general inflammatory biomarkers not specific for NMOSD and that satralizumab has not been studied in any disease model in vivo, additional clarification regarding the mechanism of action of satralizumab and the role of classical signalling and trans-signalling in NMO was required by the Applicant.”