Biosimilars: Extrapolation for oncology

- A biosimilar is a biologic that is highly similar to a licensed biologic.
- Biosimilarity is established based on analytical, non-clinical and clinical studies.
- Extrapolation is essential to the biosimilar concept and is based on scientific principles.
- The main rationale for data extrapolation is to avoid unnecessary studies.
- Biosimilars function similar to the originators including in indications that were licensed based on extrapolation.

A biosimilar is a biologic that is highly similar to a licensed biologic (the reference product) in terms of purity, safety and efficacy. If the reference product is licensed to treat multiple therapeutic indications, extrapolation of indications, i.e., approval of a biosimilar for use in an indication held by the reference product but not directly studied in a comparative clinical trial with the biosimilar, may be possible but has to be scientifically justified. Here, we describe the data required to establish biosimilarity and emphasize that indication extrapolation is based on scientific principles and known mechanism of action.