Introduction to biosimilar and interchangeable products
Biological, pharmaceutical products, or biopharmaceutical products constitute the largest category of new regulatory filings; over two-thirds of all new drugs will be biologicals, as projected by the industry. Since “bioequivalence” had long been used to denote generic products, the regulatory agencies shied away from using the terminology in common use for chemical generic drugs. The concept of biosimilarity rather than bioequivalence emerged globally, and this terminology is widely accepted, even though some agencies continue to promote “follow-on biologics,” “subsequent entry biologics”, “biocomparables,” and other peculiar labels. The differentiation of products from being therapeutically interchangeable to biosimilar had its roots in the size of active molecules; compared with synthetic small molecules, biologics are 100–1000 times larger in size, having several hundred amino acids. Generally, one would assume that the first interchangeable biologic product will appear in the United States, but the Government of France, in a dramatic move, declared biosimilar products to be interchangeable.