VR81

VR81 is an anti-mouse monoclonal antibody that targets the granulocyte-colony stimulating factor receptor (G-CSFR). It serves as a preclinical surrogate for CSL324, a humanized anti-G-CSFR antibody developed by CSL Behring. VR81 is utilized in research to investigate the role of G-CSF signaling in the pathophysiology of sickle cell disease (SCD), specifically its contribution to thrombo-inflammation and vaso-occlusive crises (VOC). By antagonizing G-CSFR, VR81 inhibits neutrophil activation and the formation of neutrophil extracellular traps (NETs), which are key drivers of microvascular occlusion. Preclinical studies in humanized SCD mouse models have demonstrated that VR81 can both prevent and resolve vaso-occlusion and reduce chronic organ injury, supporting the clinical development of G-CSFR blockade for VOC prevention.