An introduction to biosimilar cancer therapeutics: definitions, rationale for development and regulatory requirements.

Monoclonal antibodies and other biologic drugs play important roles in the treatment of various hematological malignancies and solid tumors. However, such drugs are intrinsically more expensive to develop than small molecules and their clinical benefits are often accompanied by challenges relating to affordability and access. Patent expiry for 'originator' biologics is providing opportunities for a new generation of biosimilar drugs, potentially capable of relieving pressure on healthcare budgets. This article discusses key characteristics of biosimilars, distinguishes them from generics and noncomparable biologics and outlines the robust regulatory requirements that must be followed to establish biosimilarity with a reference product. The path to approval is discussed with reference to the rituximab biosimilar CT-P10, the first licensed monoclonal antibody biosimilar cancer therapeutic.