[Biosimilar medicines: Regulatory issues and medico-economic impacts]

The concept of biosimilar medicine was launched by 2001 and 2004 European Directives. First European marketing authorizations were delivered in 2006. They are "copies" of biologically manufactured medicines, mostly proteins. Taking into account the intrinsic variability related to the biological manufacture process, some variation of the chemical structure of the finished compound may be observed. They impact especially the glycosylation residues but not the amino-acid sequence (for proteins). For this reason, the marketing authorization application dossier has to involve, as opposed to the generic medicine procedure, the demonstration of the therapeutic equivalence in at least one clinical indication of the princeps medicine. Introduction of biosimilar medicines of monoclonal antibodies has represented a remarkable event in the domain of rheumatology, gastroenterology and dermatology with infliximab, etanercept and adalimumab biosimilars and in cancerology domains with rituximab, trastuzumab and bevacizumab biosimilars. Biosimilar medicines availability reduces the risk of drug supply rupture of princeps but their main impact is the economic one allowing cost reduction of costly princeps biological medicines. With the acquired clinical experience, the initial fears concerning switch form princeps to a biosimilar for a given patient has progressively disappeared.