Lilly finds bacteria, other impurities in Mounjaro, Zepbound knockoffs

(Reuters) -Eli Lilly said on Thursday it has found bacteria and high levels of impurities in products claiming to be compounded versions of tirzepatide, the active ingredient in its popular diabetes drug Mounjaro and weight loss treatment Zepbound.

The U.S. drugmaker has sued several medical spas, weight-loss clinics and compounding pharmacies to stop them from selling products purporting to contain tirzepatide.

Compounded drugs are custom-made medicines based on the same ingredients as branded versions, and often cheaper, but also subject to less regulatory scrutiny.

In an open letter, Lilly said some of these products had a different chemical structure as well as a different color than the approved versions of Mounjaro or Zepbound.

"In at least one instance, the product was nothing more than sugar alcohol," Lilly said.

The company said it does not sell or provide tirzepatide to any compounding pharmacies.

"Lilly rightly notes that compounded drugs are not FDA-approved. But that fact does not mean compounded drugs are unsafe – any more than it means that FDA-approved drugs are always safe," said Scott Brunner, CEO of the Alliance for Pharmacy Compounding, which represents compounding pharmacists and technicians.

Brunner said it was not clear if the fake drugs were made at a state-licensed pharmacy, which can legally produce compounded drugs when the branded version of a drug is in short supply, in which case they would not be compounded drugs.

Danish rival Novo Nordisk has also taken legal action against those offering products that claim to contain semaglutide, the active ingredient in its popular weight loss drug, Wegovy.

Novo reported in December it had found some samples of compounded semaglutide to be up to 33% impure.

(Reporting by Bhanvi Satija and Sneha S K in Bengaluru; Editing by Shinjini Ganguli)