BAY 1213790, a Fully Human IgG1 Antibody Targeting Coagulation Factor XIa: 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 (FXIa), 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.