The treatment of rheumatoid arthritis (RA) and other forms of spondyloarthritis was revolutionized at the end of the 1990s, after the emergence of the so-called tumour necrosis factor alpha antagonists (anti-TNFα), which are biodrugs, also known as biopharmaceuticals, produced using biotechnology [1]. The gene discussed is TNF; the disease is rheumatoid arthritis.