Safety, pharmacokinetics and pharmacodynamics of BI 655064 in phase 1 clinical trials in healthy Chinese and Japanese subjects

Aims: To evaluate the safety, pharmacokinetics and pharmacodynamics of BI 655064 in healthy Chinese and Japanese subjects after administration of single doses of 80-240 mg and multiple dosing of 240 mg once weekly over 4 weeks.

Methods: Two phase 1, double-blind, placebo-controlled studies were conducted (single-rising doses of BI 655064 in Chinese/Japanese male subjects [n = 12 per BI 655064 dose group] or repeated 240 mg BI 655064 in Chinese male subjects [n = 9]). Plasma samples were collected to investigate BI 655064 pharmacokinetics, pharmacodynamics (CD40 receptor occupancy [RO]) and immunogenicity, along with the safety and tolerability of BI 655064.

Results: BI 655064 showed good overall tolerability following single-dose administration of 80-240 mg and repeated administration of 240 mg BI 655064 over 4 weeks. More Chinese subjects reported adverse events compared with Japanese subjects following single-dose administration (59.4% vs 3.1%). BI 655064 exhibited nonlinear, saturable kinetics, with higher doses resulting in slower apparent clearance (0.514-0.713 mL min^-1 ), and disproportionately higher total exposure (AUC_0-inf ; 5610-7780 μg·h mL^-1 ) and maximum plasma concentration (15 700-21 300 ng mL^-1 ) with 240 mg BI 655064. Ninety percent inhibition of CD40 RO was achieved with doses ≥120 mg, and a direct relationship between BI 655064 plasma concentration and inhibition of CD40 RO was observed. Most subjects had a positive treatment-emergent antidrug antibody response.

Conclusions: BI 655064 pharmacokinetic and safety profiles in East Asian male subjects were consistent with those observed in a Western population. No adjustments in the BI 655064 dosing recommendations are warranted for future clinical trials.