Fenoprofen (LILLY-53858) is a nonsteroidal anti-inflammatory agent (NSAID) and inhibits cyclooxygenase (COX) . Fenoprofen is a melanocortin receptors (MCRs) positive allosteric modulator (PAM) . Fenoprofen also increases ERK1/2 activation in HEK293T cells. Fenoprofen has anti-arthritic activities and can be used for the study of rheumatoid arthritis and osteoarthritis[1][2].