Factor XI/XIa inhibition pursued for low-bleeding anticoagulation
- Factor XI and its active form XIa amplify thrombin generation and drive pathological thrombosis, yet contribute little to normal hemostasis, which makes them a candidate target for anticoagulants with lower bleeding risk.
- The review covers FXI/XIa structure, structure-guided design and the main therapeutic modalities, with critical appraisal of clinical evidence across thrombotic indications.
- Open issues include selectivity, disease-dependent efficacy and FXI roles beyond coagulation, all bearing on long-term safety and clinical positioning.
💡 Points
FXI's appeal rests on human genetics (congenital deficiency, little spontaneous bleeding) more than on animal models, and that is the credible part. What I'd probe is the exposure ceiling: if the efficacy window is narrow and trough inhibition drifts, you lose the bleeding advantage. Off-target serine protease selectivity against FXa, thrombin and kallikrein decides whether the margin is real.