United States Patent number 1,469,994 for the manufacture of insulin is awarded to J. B. Collip, C. H. Best and F. G. Banting.
Image Source: https://heritage.utoronto.ca/exhibits/insulin

In an arduous effort to restore the Connaught Laboratories’ pancreatic extract production, the major concern of the discovery team was pertaining to the protection of the discovery of the soon-to-be-named “insulin” from exploitation by a clever chemist or an enterprising, and perhaps disreputable, drug company. Being identified that patenting the discovery was the only method to safeguard their relentless effort, the discoverers gained patent for the discovery and subsequently on December 19th, Banting, Best and Collip formally assigned their full patent rights to the University of Toronto Board of Governors for $1.

Banting famously said, “Insulin does not belong to me, it belongs to the world.” He wanted everyone who needed it to have access to it. The growing demand for insulin challenged the Toronto University with respect to the mass production of insulin which was later resolved by choosing Eli Lilly as the manufacturing partner. The agreement launched a unique and intensive one-year exclusive partnership focused on developing large-scale insulin production methods. Eli Lilly become the first manufacturer to mass produce insulin and in October 1923 they began shipping the first commercial supply of insulin. The agreement also allowed Eli Lilly to take out U.S. patents on any improvements it made in the manufacturing process, but it would assign patent rights for the rest of the world to the University of Toronto. The agreement also briefly mentioned the use of Eli Lilly trade names, with “Iletin” (a modification of the “isletin” name Banting and Best gave the extract during their lab research) designated as Eli Lilly’s brand name for insulin.