Licensing of biosimilars promotes wider patient access to essential medicines.
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Currently, regulators require comparative efficacy trials for complex biosimilars.
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On review, these trials contribute little additional evidence of biosimilarity.
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Extensive analytical testing and a pharmacokinetic study are usually sufficient.
Licensing of biosimilars is essential to promote patient access to 21st-century biological medicines. Regulatory approval of biosimilars is based on the totality of evidence from a head-to-head comparison with reference products (RPs). A clinical efficacy trial is usually required, but this is increasingly questioned. Based on a thorough review of biosimilar applications in the European Union (EU), we conclude that in-depth knowledge of the reference product, allied with high-performing analytical tools, largely predicts clinical comparability, subject to confirmation by a comparative pharmacokinetic (PK) trial. We provide a blueprint for a biosimilar pathway that reduces the need for clinical efficacy trials in exceptional cases, together with qualifying criteria and requirements for streamlined assessment to expedite wider access to affordable biological medicines.