Two phase 1 randomised studies investigating the safety and pharmacokinetics of bepranemab in healthy participants of different ethnicities

Background Bepranemab is a recombinant, humanised, full-length IgG4 monoclonal antibody targeting a mid-region tau epitope. Two phase 1 studies assessed the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of bepranemab. Methods UP0047 ( NCT03464227 ) and UP0065 ( NCT03605082 ) were phase 1, double-blind, placebo-controlled, single-dose, dose-escalation studies of intravenous bepranemab in healthy participants (Caucasian and Japanese descent, respectively). Primary endpoint: safety and tolerability of single ascending doses of bepranemab. PK were assessed in serum and cerebrospinal fluid (CSF); PD (levels of free tau) in CSF. A physiologically based PK/PD (PBPK/PD) model was developed to predict dose response. Results UP0047: Caucasian participants (N=52) were randomised to bepranemab 0.3 mg/kg, n=2; 1 mg/kg, n=6; 3 mg/kg, n=6; 10 mg/kg, n=6; 30 mg/kg, n=6; 60 mg/kg, n=6; 120 mg/kg, n=6; placebo, n=14). UP0065: participants of Japanese descent (N=24) were randomised to bepranemab 30 mg/kg, n=6; 60 mg/kg, n=6; 120 mg/kg, n=6; placebo, n=6). No serious treatment-emergent adverse events (TEAEs) or discontinuations due to TEAEs were observed. One participant (bepranemab 60 mg/kg) experienced treatment-related TEAEs of headache (moderate intensity), nausea and vomiting (mild intensity). There was no effect of ethnicity on PK parameters. A dose-response effect of bepranemab on free tau levels was observed. Data applied to a PBPK/PD model supported a dose of 90 mg/kg of bepranemab every 4 weeks to achieve a reduction in mean change from baseline in free tau levels of up to 90%. Conclusions Safety, PK and PD data support continued investigation of bepranemab for the treatment of tauopathies.