Fibrin

Class

Fibrin-targeting monoclonal antibody

Fibrin is the insoluble protein meshwork that forms when the enzyme thrombin cleaves circulating fibrinogen, producing the structural scaffold of a blood clot. Beyond this well-known role in stopping bleeding, fibrin has a second, less familiar function: when blood vessels become leaky, as happens when the blood-brain barrier or blood-retina barrier is compromised, fibrinogen escapes into surrounding tissue and is converted to fibrin there. This extravascular fibrin can bind receptors on immune cells and trigger chronic inflammatory signaling, contributing to tissue injury in neurodegenerative and vascular diseases. A monoclonal antibody engineered to bind fibrin selectively can be designed to block this inflammatory signaling function while leaving fibrin's clot-forming architecture undisturbed, a distinction that separates it from conventional anticoagulants, which suppress clot formation broadly and carry bleeding risk. The rationale for this approach is to interrupt a self-perpetuating cycle of vascular leakage and inflammation without touching normal hemostasis. This mechanism is of interest in conditions marked by barrier breakdown and fibrin deposition outside blood vessels, including neuroinflammatory and neurodegenerative disorders and retinal vascular disease, where reducing fibrin-driven inflammation could limit ongoing tissue damage.