Eli Lilly's early commercial insulin production (Iletin)

In 1923 Eli Lilly and Company in Indianapolis began large-scale commercial production of insulin under the brand name Iletin after obtaining rights from the University of Toronto. Lilly developed standardized, factory-scale processes and one of the first U.S. mass-production lines for a biotech drug, enabling wider clinical availability of insulin in the United States. This manufacturing work at Lilly's Indianapolis facilities is documented in pharmaceutical histories of early insulin distribution. The effort represents an early example of industrial-scale biopharmaceutical production in the U.S.