# Biosimilar A **biosimilar** is a highly similar, clinically equivalent version of an approved **biologic** drug (drugs made from living cells, like insulin, Humira, or cancer antibodies). Because biologics can't be exactly copied the way small-molecule generics can, biosimilars require their own approval pathway — but once on the market they can sharply lower prices. ## Why It Matters Biosimilars are where drug-price *competition* is supposed to happen for the most expensive medicines — yet entry is routinely delayed. [[Patent Evergreening]] (thickets of secondary patents) and **rebate walls** (see [[Drug Rebate]]) let incumbents block or marginalize biosimilars even after launch; the Humira biosimilars saga is the textbook case, where multiple cheaper versions launched but PBM [[Formulary]] choices initially preserved the originator's dominance. Biosimilar uptake is a key test of whether U.S. [[Drug Pricing]] reform actually reaches patients. See [[Drug Pricing]].