A fight over how to count the building blocks of a single molecule is now shaping when Americans might get access to a lower-priced version of the most powerful obesity drug in development.
Eli Lilly confirmed this month that it will still pursue a biologics license application for retatrutide, the triple-hormone injection that produced weight loss topping 20 percent at 80 weeks in two late-stage trials, even though the Food and Drug Administration has determined the medicine is neither a protein nor a biological product. The litigation behind that disagreement has been running quietly since September 2024, when Lilly sued the agency, and it remains unresolved in federal court.
