Rabeximod is an indolo[2,3-b]quinoxaline derivative patented by OxyPharma AB as anti-inflammatory agent useful for the treatment of autoimmune disease. Rabeximod impaired monocyte differentiation into monocyte-derived dendritic cells and pro-inflammatory allostimulated macrophages. Monocyte-derived dendritic cells that were treated with Rabeximod resulted in a significant decrease in their ability to pinocytose antigens, while no effect was exerted by the drug on the ability of allostimulated macrophages and anti-inflammatory macrophages to phagocytose. Rabeximod reduces the severity of arthritis in rodent models of rheumatoid arthritis and multiple sclerosis. Rabeximod efficiently prevented arthritis during the time window when TLR2 or TLR4 ligands activate inflammatory macrophages.