Low molecular weight heparins copies : have they to be considered generics or biosimilars?

Low molecular weight heparins (LMWHs) represent a class of compounds widely used in the prophylaxis of thrombosis in patients undergoing to surgical interventions. They are manufactured by chemical or enzymatic degradation of heparin which is obtained by extraction from porcine gut. According to the depolymerisation method, LMWHs differ for composition, average molecular weight and distribution and physico-chemical properties. As a consequence, their therapeutic indications present some differences. The expiration of protection rights gives the opportunity to the development of copies of the innovator\u2019s product. In this case, the Marketing Authorisation Application can be handled as an abridged application presenting a reduced dossier. FDA classifies LMWHs chemicals and the copies are referred as generics; while EMA considers as biological medicines and the copies are referred as biosimilars. As a consequence, EMA requires appropriate powered clinical trials to establish comparable efficacy and safety between copies and innovator product, while FDA requires only in human pharmacodynamic studies. The quality, efficacy and safety of LMWHs represent a hot topic continuously debated and in evolution as demonstrated by the continuous revision of the existing guidelines. Conceivably, taking into account the intrinsic variability of LMWHs obtained also by using the same depolymerization method and the objective current impossibility to completely characterize such complex compounds, a conservative approach is desirable as it guarantees a higher level of safeness for the patient\u2019s health. Reasonably, a reduction of the amount of clinical studies required by EMA, supported by a more specific chemical and analytical characterization, is the best direction to be pursued in order to ease the introduction on the market of the biosimilar products of LMWHs assuring at the same time the efficacy and safety of these drugs