Biosimilars are biological medical products that are highly similar to already approved innovator drugs. In biosimilar development, the main goal is not to show safety and efficacy, but rather to demonstrate similarity to the innovator product in key areas, such as pharmacokinetics, pharmacodynamics and evaluation of efficacy, safety and immunogenicity in clinical studies.
The FDA and its European counterpart, the EMA, as well as the World Health Organization have released guidelines on the development of biosimilars. All regulating bodies acknowledge the difficulties of biosimilar development. Each candidate drug has unique aspects that will require a case-by-case drug development program. For approval in the US, the biosimilar must be shown to be similar to the innovator product released on the US market and similarly, EU-approved biosimilars must be similar to their approved counterparts on the EU market. However, in order to facilitate global development programs, some foreign products are allowed in comparative clinical studies provided there is a scientific rationale of doing so.