Biosimilars Have Arrived: Rituximab.

A biosimilar is a biologic product that is highly similar to a licensed biologic ("originator") such that there are no clinically meaningful differences in safety, purity, or potency between the biosimilar and the originator. As patent protection and data exclusivity for the biologic rituximab expire, several potential biosimilars to rituximab are in development, which could soon lead to the availability of numerous rituximab biosimilars. Biosimilars are evaluated using thorough and rigorous analyses of the potential biosimilar versus the originator biological to confirm similar structure, function, and clinical efficacy as well as safety. Approval of a biosimilar is based upon the totality of the evidence demonstrating similarity to the originator. An understanding of the process of the interchangeable designation of a biosimilar is important in the context of patient outcomes. We conducted an analysis of the properties and benefits of rituximab in the treatment of inflammatory diseases, the development and approval of biosimilars, and the potential benefits of rituximab biosimilars. PubMed and ClinicalTrials.gov databases were searched for "biosimilar" and "rituximab" and regulatory and pharmaceutical company web pages were screened regarding biosimilars in development and specific guidelines developed for the approval of biosimilars. The results indicate that, at present, six rituximab biosimilar candidates are undergoing comparative clinical development, and two were recently approved in the European Union. Our analysis indicates rituximab biosimilars are expected to have a continuing role in treating inflammatory conditions such as rheumatoid arthritis.