R69-4

R69-4 is a recombinant monoclonal antibody that targets the F4 epitope of type-II collagen (COL2). Developed by researchers at the Karolinska Institutet and Vacara AB, it is being investigated for the treatment of rheumatoid arthritis (RA). The antibody works by binding to COL2 and subsequently inhibiting the signaling of the activating Fc gamma receptor 3 (FCGR3) on neutrophils and synovial macrophages. In humanized mouse models (HLA-DRB1*0401), R69-4 has demonstrated the ability to significantly reduce arthritis severity, particularly during the onset phase, by modulating the inflammatory response without broadly depleting autoantibodies. This targeted approach aims to provide a more specific therapeutic option for RA patients, especially during early disease stages.