By Patrick Wingrove

(Reuters) -Novo Nordisk said on Thursday it sued one compounding pharmacy and refiled a lawsuit against another after finding their products claiming to contain the active ingredient for its in-demand weight-loss drug Wegovy were impure, some by as much as 33%.

The Danish drugmaker said it found impurities in all the drugs tested from Wells Pharmacy and Brooksville Pharmaceuticals, both based in Florida. Novo first sued Brooksville in July, and discovered a substance called BPC-157 in samples from Wells.

Both cases were filed in Florida on Wednesday.

Brooksville managing partner Terry Myers said in an email the company disputes the new allegations and plans to file another motion to dismiss. Wells did not respond to a request for comment by email on Thursday.

The U.S. Food and Drug Administration banned BPC-157 from use in compounded drugs in September, saying it did not have enough data to know whether it was harmful to humans, but that it could cause dangerous immune system reactions.

Novo said the compounded versions of Wegovy tested from Brooksville were also less potent than advertised, with one sample shown to be at least 19% weaker than indicated.

“Compounded products do not have the same safety, quality and effectiveness assurances as FDA-approved drugs, and adulterated and misbranded injectable compounded drugs may expose patients to significant health risks,” Jason Brett, a Novo Nordisk executive, said in a statement.

Novo said the lawsuits aim to stop the two pharmacies from selling products claiming to contain semaglutide - the main ingredient in Wegovy and Ozempic - and prevent Wells Pharmacy from claiming its products are FDA approved or that BPC-157 has health benefits without making customers aware of its safety risks.

Brooksville's Myers said the company buys its bulk ingredients, including semaglutide, from FDA-registered facilities.

It has tested its formulation with a third-party lab and found it remains potent for 180 days when stored in a refrigerator, 90 days when stored at room temperature and 45 days when stored at 40 degrees Celsius.

Novo has already filed 12 lawsuits against medical spas, weight-loss clinics and compounding pharmacies offering products that claim to contain semaglutide.

The company said it had obtained temporary orders against six of those to stop them claiming their products are authentic, FDA approved or associated with Novo Nordisk.

Novo's biggest rival in the obesity drug market, Eli Lilly, has also sued several medical spas, weight-loss clinics and compounding pharmacies this year to stop them from selling products purporting to contain tirzepatide, the active ingredient in its diabetes drug Mounjaro and recently-approved weight loss medicine Zepbound.

The case against Wells was filed in the U.S. District Court, Middle District of Florida, Ocala division and the suit against Brooksville in U.S. District Court, Middle District of Florida, Tampa division.

(Reporting by Patrick Wingrove; Additional reporting by Josephine Mason;Editing by Bill Berkrot, Jane Merriman and Susan Fenton)