BAY 1213790, a fully human IgG1 antibody targeting coagulation factor XI a: First evaluation of safety, pharmacodynamics, and pharmacokinetics

Background Coagulation factor XI ( FXI ) contributes to the development of thrombosis but appears to play only a minor role in hemostasis and is therefore an attractive anticoagulant drug target. Objectives To evaluate the safety, pharmacodynamic, and pharmacokinetic properties of BAY  1213790, a fully human immunoglobulin (Ig) G1 antibody targeting activated coagulation FXI ( FXI a), in healthy men. Methods In this phase 1, single‐blind, parallel‐group, placebo‐controlled, dose‐escalation study, 83 healthy Caucasian men were randomized 4:1 to receive a single 60‐minute intravenous infusion of BAY  1213790 (0.015‐10 mg/kg) or placebo. Adverse events, pharmacodynamic parameters (including activated partial thromboplastin time [ aPTT ]) and pharmacokinetic parameters were determined. Volunteers were followed up for 150 days. Results BAY  1213790 demonstrated favorable safety and tolerability; there were no observed cases of bleeding or clinically relevant antidrug antibody formation. One volunteer (1.2%) experienced an infusion reaction. Following intravenous administration of BAY  1213790, dose‐dependent increases in aPTT (maximal mean increase relative to baseline: 1.85 [conventional method] and 2.17 [kaolin‐triggered method]) and rotational thromboelastometry whole blood clotting time were observed, as well as dose‐dependent reductions in FXI activity. Bleeding times did not increase following administration of BAY  1213790 and were similar for all dose cohorts, including placebo. Measurable and dose‐dependent increases in systemic exposure were detected for all doses of BAY  1213790 of 0.06 mg/kg or higher. Conclusions Based on these safety, pharmacodynamic, and pharmacokinetic results, further evaluation of BAY  1213790 in patients with, or at risk of, thrombosis is warranted.