The safety of emerging biosimilar drugs for the treatment of rheumatoid arthritis.

Biological disease-modifying anti-rheumatic drugs (bDMARDs), often administered in combination with methotrexate, target specific inflammatory mediators and have transformed the treatment of rheumatic diseases, especially rheumatoid arthritis (RA) but also the spondyloarthritides. However, the high cost of these drugs in many countries restricts patient access. As many bDMARDs have reached or are near to patent expiration, numerous biosimilar drugs are in development and some have already been approved. Biosimilars are generally priced lower than their reference products (RPs), or bio-originators, and as prices come down it is hoped that patient access to these drugs will increase, making the safety of these drugs an area of major interest. Areas covered: This article reviews publicly available safety data on biosimilars in RA. Expert opinion: Most available data for biosimilars in RA relate to tumor necrosis factor inhibitors (TNFi) and rituximab (an anti-CD20 monoclonal antibody). As biosimilar use around the world increases, evidence supporting the clinical safety of the biosimilars compared with their RPs also grows. To date, no new safety concerns have been raised in studies with TNFi or rituximab biosimilars for the treatment of RA; safety profiles have been consistent with those of their RPs. However, careful post-marketing pharmacovigilance remains necessary.