AP21

AP21 is a novel, high-affinity monoclonal antibody targeting the C-domains (specifically the C2-C3 domain region) of Von Willebrand Factor (VWF). Developed by Apollo Therapeutics in collaboration with Imperial College London, AP21 is designed as a shear-dependent antithrombotic therapy. It selectively inhibits VWF-dependent platelet capture and aggregation under high pathological shear rates while preserving normal platelet capture at physiological shear, thereby offering a lower risk of bleeding compared to traditional antithrombotics. AP21 has demonstrated efficacy in reversing the thrombotic phenotype in a murine model of thrombotic thrombocytopenic purpura (TTP) and has shown a favorable safety and pharmacokinetic profile in non-human primates.