Limited access for high-quality biologics due to cost of treatment constitutes an unmet medical need in the US and other regions of the world. The term “biosimilar” is used to designate a follow-on biologic that meets extremely high standards for comparability or similarity to the originator biologic drug that is approved for use in the same indications. Use of biosimilar products has already decreased the cost of treatment in many regions of the world and now a regulatory pathway for approval of these products has been established in the US. The Food and Drug Administration (FDA) led the world with the regulatory concept of comparability and the European Medicines Agency (EMA) was the first to apply this to biosimilars. Patents on the more complex biologics, especially monoclonal antibodies, are now beginning to expire and biosimilar versions of these important medicines are in development. The new Biologics Price Competition and Innovation Act (BPCIA) allows the FDA to approve biosimilars and allows the FDA to lead on the formal designation of interchangeability of biosimilars with their reference products. The FDA's approval of biosimilars is critical to facilitating patient access to high-quality biologic medicines and will allow society to afford the truly innovative molecules currently in the global biopharmaceutical industry's pipeline.

IntroductionTo evaluate the possibility that switching from reference biologic medicines to biosimilars could lead to altered clinical outcomes, including enhanced immunogenicity, compromised safety, or diminished efficacy for patients, a systematic literature review was conducted of all switching studies between related biologics (including biosimilars).MethodsA systematic search was conducted using the Medline® and Embase® databases up to 30 June 2017 employing specific medical subject heading terms. Additionally, the snowball method and a hand search were also applied. Publications were considered if they contained efficacy or safety information related to a switch from a reference medicine to a biosimilar. Non-English, non-human studies, editorials, notes, and short surveys were excluded.ResultsPrimary data were available from 90 studies that enrolled 14,225 unique individuals. They included protein medicines used in supportive care as well as those used as therapeutic agents. The medicines contained seven different molecular entities that were used to treat 14 diseases. The great majority of the publications did not report differences in immunogenicity, safety, or efficacy. The nature and intensity of safety signals reported after switching from reference medicines to biosimilars were the same as those already known from continued use of the reference medicines alone. Three large multiple switch studies with different biosimilars did not show differences in efficacy or safety after multiple switches between reference medicine and biosimilar. Two publications reported a loss of efficacy or increased dropout rates.ConclusionsWhile use of each biologic must be assessed individually, these results provide reassurance to healthcare professionals and the public that the risk of immunogenicity-related safety concerns or diminished efficacy is unchanged after switching from a reference biologic to a biosimilar medicine.Electronic supplementary materialThe online version of this article (10.1007/s40265-018-0881-y) contains supplementary material, which is available to authorized users.

The development of biologic therapeutics using advanced technology to copy and improve on nature's design of complex peptides, proteins, and glycoproteins has enabled the treatment of diseases in entirely new ways and brought unique and lifesaving treatments to many people. However, at least in part because of cost pressures, access to these truly amazing products has not been uniformly available; many patients do not qualify for these treatments, or the treatment is postponed until disabilities accumulate. The development of biosimilars--essentially copies of the original biologic drugs after patent expiration--allows for wider and, as important, earlier access to these agents because of their lower cost and consequently greater affordability. The development and commercialization of biosimilars can help address unmet medical needs by improving access to well-established therapeutic interventions while improving health-care affordability.

The molecular forms and antigenic heterogeneity of the leukocyte-common antigen (L-CA) of rat lymphocytes have been analyzed. Thymocytes show one main band at 180 kDa, T cells four bands at 180, 190, 200 and 220 kDa and B cells one broad band at about 240 kDa. T helper and T cytotoxic cell subsets show the same four bands with some differences in the proportion of each. Four mouse monoclonal antibodies (MRC OX-1, 28, 29 and 30) reacted with all molecular forms of L-CA and fell into two sets that were noncompetitive in binding to L-CA (MRC OX-1, 28, 29 vs. OX-30). The antigenic determinants seen by all these antibodies were lost when L-CA was reduced and alkylated. Three antibodies (MRC OX-22, 31 and 32) reacted selectively with B cells, T cytotoxic cells and about 2/3 of T helper cells. OX-22 and OX-31 competed for binding but were noncompetitive with OX-32. All these antibodies bound to a subfraction of the 190, 200 and 220-kDa forms of T cell L-CA but not at all to the 180-kDa form of T cells or thymocytes. One antibody bound to B cells only (MRC OX-33) and precipitated a subfraction of B cell L-CA. With all the antibodies that did not label thymocytes the antigenic determinants survived reduction and alkylation. Subsequent proteolysis with trypsin then destroyed all determinants except the one reacting with MRC OX-22 antibody. In this case tryptic peptides retained full antigenic activity which was, however, destroyed by further proteolysis with pronase.