FPR1 and rheumatoid arthritis: For example, the FPR1/FPR2 mixed agonist Cpd43 (Figure 1) synthesized by Amgen, proved to be beneficial in animal models (collagen-induced and antigen-induced arthritis) of RA [14], significantly reducing the tissue inflammation, cartilage damage, and synovitis [6] at a dose of 30 mg/kg (i.p.).