Fig. 5. Characterization of type I and type II mAbs in monkeys.

a, b TM–TGA in monkey plasma: a ETP and b peak thrombin levels. c, d Protac-aPTT in FVIII Ab-treated monkey plasma: c clotting time with IC₅₀ values of 9.3 vs. 19.3 nM and d % inhibition with IC₅₀ values. Experiments were performed with triplicate samples in (a, b) and duplicate samples in (c, d); data points reflect their average in each assay, and assays were repeated ≥3 times. e–j Testing mAbs in vivo. Plasma PC levels (μg/mL) in type I-treated (e) and in type II-treated (f) wild-type cynomolgus monkeys. Each bar represents the mean value ± SD of 3–6 measurements from one monkey (e) and two monkeys (f). g Pharmacokinetic profiles (c/t curves) of both mAbs at 3 mg/kg administered intravenously in wild-type cynomolgus monkeys. h, i Development of severe HemA monkey bleeding model and testing acute efficacy of type II mAb. h Plasma FVIII activity (IU/mL) in monkeys (n = 10 independent animals) before and after treatment with anti-FVIII antibody (no Ab vs. anti-FVIII Ab). LLOQ means the lower limit of quantification (0.04 IU/mL). Box and whiskers are based on the Tukey’s method with the center line representing median, box representing interquartile range (IQR) between 25th and 75th percentiles, and whiskers representing 25th or 75th percentile plus 1.51 IQR. i Total bleeding time in second(s) post injury in normal monkeys (i.e., no treatment: Trmt−) and in HemA monkeys (i.e., treated with anti-FVIII antibody: α-FVIII), as well as in HemA monkeys treated with type II mAb at 3 and 10 mg/kg or with the known procoagulant rFVIIa (recombinant activated factor VII) at its pharmacological dose (270 µg/kg) as control. p Values < 0.05 are indicated (one-way ANOVA with Dunnett’s multiple-comparison test). N = 10 monkeys per group. j Median hemoglobin remaining, 72 h post administration of BO2C11-cynoIgG1 (t = 0) and intramuscular needle injury (t = 2 h), as a readout of prophylactic efficacy of type II mAb in HemA cynomolgus monkeys. Median values of hemoglobin remaining in each group as % of non-hemophilic animals are shown by lines. * in the saline group denotes two monkeys that died.