Biosimilars: lights and shadows in rheumatology

In the last 10 years, the growing approval and marketing of biological agents has significantly ameliorated the outcomes of rheumatoid arthritis and spondyloarthritis patients suffering from active and refractory disease despite conventional treatments. As patent protection of many biopharmaceuticals will expire in the next years, biosimilars could be proximally introduced. Such agents could be marked only when they will be proven, through in vitro and in vivo studies, to be similar enough to the original comparator in term of quality, efficacy and safety. As biosimilars are less expensive than corresponding originators, a wider use of these drugs may substantially cut off the expenditure of biopharmaceuticals. Nevertheless, ongoing debate exists in scientific community: the intrinsic complex and large structure of biologic molecules besides the natural variability in the manufacturing processes might lead to a slightly different product respect to the original one, so that relevant implications for efficacy and safety concerns might arise, especially in the long-term period. Immunogenicity and extended indications of biosimilars represent further matter of discussion, too. Thus, before their approval and marketing, specific guidelines and steps imposed by national and/or international regulatory agencies should be followed along with the respect of scientific societies position in each specific contest.