Biosimilars are biologic products that are highly similar to, and have no clinically meaningful differences from, the approved originator molecule. They are poised to play an increasingly central role in cancer treatment, helping to improve access by driving down costs. Regulatory bodies have set out robust mechanisms for the approval of biosimilars, based on comprehensive and rigorous analytical and nonclinical comparisons with the originator. Product attributes (e.g., post-translational modifications) that are important to the function of the molecule must be similar between biosimilar and originator. This should be followed by a robust clinical development program, assessing pharmacokinetics, pharmacodynamics, efficacy, safety and immunogenicity. Equivalence in one indication might allow extrapolation across all the indications of the originator biologic. The recent approval of several trastuzumab biosimilars provides an example of how this process can work in practice for the benefit of patients, clinicians and payers.
Keywords: SB3; biologic; biosimilar; breast cancer; trastuzumab.