Biosimilar agents in oncology/haematology: from approval to practice

The regulation of biosimilars is a process that is still developing. In Europe, guidance regarding the approval and use of biosimilars has evolved with the products under consideration. It is now more than 3 years since the first biosimilar agents in oncology support, erythropoiesis-stimulating agents, were approved in the EU. More recently, biosimilar granulocyte colony-stimulating factors have received marketing approval in Europe. This review considers general issues surrounding the introduction of biosimilars and highlights current specific issues pertinent to their use in clinical practice in oncology. Information on marketing approval, extrapolation, labelling, substitution, immunogenicity and traceability of each biosimilar product is important, especially in oncology where patients are treated in repeated therapy courses, often with complicated protocols, and where biosimilars are not used as a unique therapy for replacement of e.g. growth hormone or insulin. While future developments in the regulation of biosimilars will need to address multiple issues, in the interim physicians should remain aware of the inherent differences between biosimilar and innovator products.