Placental transfer: monkey fetal plasma 39% and 60% of maternal at 10 and 50 mg/kg/day
“In a segment II-embryo-foetal development study in cynomolgus monkeys foetal plasma concentrations of tocilizumab were 39% and 60% of the maternal plasma concentration after application of 10 and 50 mg/kg/day, resp.”
Neutropenia from IL-6R blockade, without bone marrow changes in monkeys
“A signal toward reduction of neutrophils was observed in the 2-week toxicity study with a clear pronounced manifestation in the 4-week daily treatment cynomolgus study with no manifestation in the bone marrow.”
Immunogenic in monkeys; neutralizing ADA greatly diminished or absent at high dose; did not compromise study validity
“Neutralizing antibodies were either greatly diminished or not detected in animals treated with high dose tocilizumab. Thus, the observed immunogenicity of tocilizumab in cynomolgus monkey studies did not compromise the results of these studies and their relevance for risk extrapolation to humans.”
2% anti-tocilizumab antibody positive (5 with hypersensitivity leading to withdrawal); 1% neutralizing
“Forty-six patients (2%) developed positive anti-tocilizumab antibodies, of whom 5 had an associated, medically significant, hypersensitivity reaction leading to withdrawal. Thirty patients (1%) developed neutralizing antibodies.”
In vitro whole-blood cytokine release far below alemtuzumab/TGN1412 controls; no effects on monkey TDAR, lymphocyte subsets or serum cytokines; ADA in some monkeys