Certolizumab pegol (CZP) is an Fc-free, PEGylated anti-TNF, approved for the treatment of adult patients with rheumatoid arthritis (RA), axial spondyloarthritis (axSpA; including ankylosing spondylitis [AS] and non-radiographic axSpA), psoriatic arthritis (PsA), plaque psoriasis (PSO), and Crohn’s disease (CD) [16, 17], although registered indications vary by country. The gene discussed is TNF; the disease is rheumatoid arthritis.