Illustration: Baptiste Virot for Bloomberg Businessweek
The Big Take

How a Lucky Break Fueled Eli Lilly’s $600 Billion Weight-Loss Empire

The company’s new obesity shot, Zepbound, is expected to be the bestselling drug of all time.

If only Eli Lilly & Co. had listened to Richard DiMarchi, it could have been first to the $80 billion weight-loss drug market.

Three decades ago, DiMarchi was working as a scientist at the Indianapolis-based drugmaker, studying a gut hormone called glucagon-like peptide-1. In a small trial, he showed that an infusion of the hormone caused weight loss in humans. The finding was so promising that he and a collaborator filed a patent. All Lilly had to do was create a product using the technology and it’d have exclusive rights to sell it for weight management for at least a decade.