A biosimilar is a biological product that is highly similar to an existing FDA-approved reference product. Biosimilars are not generic versions of brand-name drugs; instead, they are comparable but not identical versions of original “innovator” biologic drugs. Generic drugs are identical to a brand-name drug in dosage form, safety, strength, route of administration, quality, performance characteristics, and intended use. Biosimilars, though highly similar to the reference product, are not exact copies.

Q codes are a type of HCPCS code used in the healthcare industry to identify services and items for Medicare beneficiaries. Codes that begin with Q5 specifically pertain to biosimilar drugs. For example, Q5118 is the Q code for the biosimilar Zirabev, a biosimilar of the cancer drug Avastin.

Below, are all biosimilar drugs and their HCPCS codes, mapped to their reference products: