Certolizumab pegol (CDP870, tradename Cimzia) is a biologic medication for the treatment of Crohn's disease, rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis. It is a fragment of a monoclonal antibody specific to tumor necrosis factor alpha (TNF-α) and is manufactured by UCB. Certolizumab pegol (CDP870, tradename Cimzia) is a biologic medication for the treatment of Crohn's disease, rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis. It is a fragment of a monoclonal antibody specific to tumor necrosis factor alpha (TNF-α) and is manufactured by UCB. Certolizumab pegol is a monoclonal antibody directed against tumor necrosis factor alpha. More precisely, it is a PEGylated Fab' fragment of a humanized TNF inhibitor monoclonal antibody. Significant side effects occur in 2% of people who take the medication.