1. biosimilar monoclonal antibodies Biologics are critical components in the treatment of patients with cancer. Biosimilars - biologics that are highly similar to approved biologics - offer a potential opportunity to increase access to biologics by stimulating price competition and may lower healthcare costs. The active substance of a biosimi­lar and the original (approved medicine) are essentially the same biological substance, though there may be minor differences due to their complex nature and the production methods.

2. A consequence of the astronomical commercial value of mAbs associated with the patent expiry date (or estimated expiry date) is their attractiveness as candidates for biosimilar drugs. An appropriate definition of biosimilars includes the following: Biologic product with primary structure identical to the reference product that has been approved in the concerned jurisdiction; Biosimilarity development pathway involving rele­vant orthogonal analytical comparability methods, and nonclinical and clinical models; Quality, nonclinical and clinical attributes are sufficiently similar, yet not necessarily identical between the biosimilar and the reference product.

3. Biosimilars are more complex than small-molecule drugs and generics. Biological medicines (Biologics) are large, complex molecules produced from living organisms that are often difficult to characterize and therefore difficult to copy. Generic medicines (Generics) usually consist of small, identical molecules that are chemically synthesized. It is important to understand several key differences between biologics and small-molecule drugs. In addition, the manufacturing process for biologics is more complex than for small-molecule drugs, which requires multiple steps for cloning; selecting, maintaining, and expanding the cell line; and isolating, purifying, and characterizing the product (Fig. 1). Small-molecule drugs are synthesized through a series of predictable chemical reactions that can be reliably reproduced to yield identical copies.

5. Biologic manufacturing includes multiple steps that may vary between manufacturers, potentially leading to differences between a biosimilar and its reference product that cannot be fully characterized with available analytical methods. In contrast, small-molecule drugs are manufactured through chemical reactions that can be reliably reproduced to make identical copies (generics) that can be fully characterized.