Crosses placenta (fetal serum ~33% of maternal) and into milk; tissue binding limited to IgE-synthesizing lymphoid cells
“Measurable levels of omalizumab were observed in amniotic fluid (~3.3% of maternal serum levels), milk (~0.154%), and fetal (~33%) and neonatal (~33%) serum.”
Thrombocytopenia (mechanism unknown, juvenile monkeys most sensitive); theoretical parasitic infection risk from IgE blockade
“In spite of the mechanistic in vivo/vitro studies performed by the Applicant, the mechanism of the omalizumab-platelet interaction and the epitope responsible for the interaction remain unknown.”
Anti-omalizumab antibodies in monkeys: non-neutralising, no effect on PK (except one juvenile) or toxicity
“Anti-omalizumab-antibodies did not affect the pharmacokinetics of omalizumab (with the exception of one juvenile monkey) nor did they have neutralising activity, nor did they elicit any toxicity, based on data from monkey toxicology studies.”
<0.1% (1/1723) in asthma patients 12 years and older
“Antibodies to XOLAIR were detected in approximately 1/1723 (<0.1%) of patients treated with XOLAIR in the clinical studies evaluated for asthma in patients 12 years of age and older.”
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