Biological medicines, such as infliximab, have been effectively used in inflammatory bowel disease (IBD) and other autoimmune inflammatory conditions with high remission rates. As the name suggests, these compounds are derived from a biological source and have a significantly larger molecular structure as compared to the standard medications. When patents for standard drugs expire, generic products are introduced to the market, which are practically identical. In the case of biological medications, however, the generic substitutes are not identical − although they are similar in structure and effectiveness. These substitute versions of biological drugs are called ‘biosimilars’.
The patent for infliximab has expired and biosimilars have entered the market at significantly reduced costs. It may be logical to think that lower pricing may result in a wider usage of this expensive, but highly effective, class of drugs.
Currently, there are no large-scale studies to support the use of biosimilars in IBD. However, promising data has been derived from two major drug trials: the PLANETRA study of 250 adult patients with rheumatoid arthritis; and the PLANETAS study of 210 adult patients with ankylosing spondylitis. These studies found the effectiveness and the side-effect profile of biosimilars to be comparable to the originator drug, infliximab. Based on the data extrapolated from these studies, there has been a massive drive in the country and across the world to switch to biosimilars. Several adult IBD units in the UK have already switched to biosimilars with encouraging outcomes, although it is still early days.
On the paediatric front, however, the current view held in Europe (ESPGHAN: European Society of Paediatric Gastroenterology, Hepatology and Nutrition) is that the treatment of children with sustained remission on infliximab should not be switched to biosimilars until robust clinical trials in IBD are available to support this change.