The advent of biosimilar therapies in rheumatology--"O brave new world".

Patents for many key biological agents will soon expire. Third-party companies are, therefore, in the process of developing their own versions, termed biosimilar agents, of these innovator products. However, manufacture of biosimilar agents is complicated by the requirement for their production in biological systems, small variations in which can influence the structure, activity and metabolism of the biosimilar product. The development of biosimilar therapies for the treatment of patients with rheumatic diseases could potentially result in substantial cost savings for patients and health care providers, and consequently, increased availability of effective therapies. However, legislation that regulates the manufacture, registration and approval of biosimilar therapies varies considerably between different countries. In addition, major safety and efficacy concerns must be addressed before a rheumatologist can routinely substitute an innovator pharmaceutical with a biosimilar product.