MMP9 and rheumatoid arthritis: We also recently showed that changes in E-selectin, interleukin (IL)-18, serum amyloid A, and matrix metalloproteinase-9 (MMP-9) are associated with improvement in clinical response measures in a phase 2 study of patients with active RA despite methotrexate (MTX) therapy, who were treated with golimumab (a human monoclonal antibody to TNF-α) [12].