Biosimilar

Biological medicines are made in living systems, which means they cannot be copied exactly the way a conventional generic copies a small-molecule drug. A biosimilar is approved on the basis that it is highly similar to an already-approved reference product and has no clinically meaningful differences from it in safety, purity, or potency.

Some biosimilars are additionally designated interchangeable, which carries implications for whether a pharmacist may substitute without consulting the prescriber. Those rules vary by jurisdiction.

Biosimilars are frequently relevant to cost, and a plan may prefer one over the reference product on its formulary. Whether switching is appropriate is a clinical question for your prescriber — this entry defines the term, and does not recommend a course of action.