Biosimilars: Comparability Requirements and Market Uptake

Biosimilars are follow-on versions of biological medicines whose approval rests on demonstrating high similarity to a reference product, not on repeating the full development programme. This narrative review describes the comparability requirements applied in Europe, the United States and under World Health Organization guidance, the analytical, nonclinical and clinical evidence that supports approval, and current thinking on immunogenicity, switching and interchangeability. It then summarises what published work shows about uptake and the policies that influence it. Uptake varies widely between countries and products, driven more by procurement and incentives than by scientific doubt. The article reports no new data; evidence gaps are discussed.