The authors point out that biopharmaceuticals are more complex agents than conventional chemical entities and therefore are more difficult to replicate after patent expiry. Off-patent versions of the originator product, moreover, cannot rely on a simple demonstration of chemical comparability; they are best described as ‘biosimilar’. These differences mean that biosimilar markets will evolve in a more complex way than traditional, small molecule, chemical generics markets.
Regulators will need clinical trial evidence of efficacy and safety before approval. Clinicians will require “patient safety year” (PSY) evidence after approval, according to the authors, that shows the equivalence in efficacy and safety of biosimilars as used in practice. Governments and other payers also should encourage pharmacovigilance and other outcomes studies that produce the PSY data that will encourage interchangeability and greater price competition.
Over time, biosimilar markets can become biogeneric, but governments and other payers need to behave differently to encourage this and realise savings. For example, price cuts after patent expiry and/or the use of reference pricing will deter biosimilar entry and reduce long term savings. Outcomes data also are important in helping assess the value for money of second generation biopharmaceutical products as compared to the first generation.