Insulin biosimilars: the impact on rapid-acting analogue-based therapy.

The impending expiration of patent protection for recombinant insulins provides the opportunity to introduce cost-saving copies, named biosimilars, onto the market. Although there is broad experience in the production and characterisation of insulins, the development of copies is still a challenge. In this paper, the main features of insulins and the EU regulatory framework for their biosimilar products are reviewed. The main focus is on rapid-acting insulin analogues (Humalog(®); Novolog(®)/NovoRapid(®); Apidra(®)). Since they differ by one or two amino acids in chain B, production of one biosimilar for all three drug products is not feasible. However, from post-marketing-collected clinical data, rapid-acting insulin analogues seem to have similar therapeutic efficacy. It is reasonable to suppose that, for prescription to treatment-naïve patients, the cheaper biosimilar would be the preferred choice of physicians, either spontaneously or induced by health insurance. Therefore, its introduction will affect the market share of all the other rapid-acting insulin analogues.