A generic drug is a pharmaceutical drug that is equivalent to a brand-name product in dosage, strength, route of administration, quality, performance, and intended use. The term may also refer to any drug marketed under its chemical name without advertising, or to the chemical makeup of a drug rather than the brand name under which the drug is sold. Biopharmaceuticals such as monoclonal antibodies differ biologically from small molecule drugs. Generic versions of these drugs, known as biosimilars, are typically regulated under an extended set of rules.