April 15 (Reuters) - The cybersecurity firm BrandShield has taken down more than 250 websites selling fake versions of popular weight-loss and diabetes drugs in the GLP-1 class, the company’s CEO Yoav Keren told Reuters.

BrandShield, which shared this information exclusively with Reuters, said that out of the 279 pharmacy websites the company closed last year for selling drugs intended to treat metabolic conditions, more than 90% were related to GLP-1 medicines, according to Keren.

Novo Nordisk’s Ozempic and Wegovy and Eli Lilly’s Mounjaro and Zepbound are GLP-1 drugs, which were developed for type 2 diabetes but also reduce food cravings and cause the stomach to empty more slowly.

The drugs have been shown to help patients lose on average as much as 20% of their weight, fueling explosive demand and a burgeoning global market for fake versions.

Cases of harm linked to fake versions of Ozempic and other GLP-1s have been reported in at least nine countries, including Belgium, Britain, Switzerland and the United States.

"I wouldn't be surprised to see criminals try to use the growing popularity of these drugs to sell more counterfeits," said Keren.

Websites taken down for selling bogus GLP-1s represented just over 15% of the 1,655 websites BrandShield reported last year for peddling counterfeit drugs in areas, including hormone-related drugs, central nervous system medicines and cancer treatments.

Websites selling counterfeit GLP-1s were less common in 2022 when the company identified 34 such sites to be closed, although it was not targeting all of the GLP-1 drugs that year as it did in 2023, said Keren.

He said his firm last year did not find the same concentration of a particular class of drug in any treatment category as it did for GLP-1s as metabolic treatments.

BrandShield worked with the Pharmaceutical Security Institute (PSI), an industry-backed organization, to take down these websites. PSI's members, which include Lilly and Novo, chose which drugs to target, according to Keren.

The CEO said his company gets these websites taken down by collecting evidence that their products are counterfeit and submitting that to the service providers hosting the site.

When permitted or requested by its drugmaker customers, BrandShield will share that intelligence with law enforcement agencies. The U.S. Food and Drug Administration said in December it was investigating counterfeit Ozempic in the legitimate U.S. supply chain.

BrandShield also took down 3,968 listings on social media platforms for fake drugs in all categories last year, almost 60% of which were found on Facebook, according to a new report from the company.

The company removed more than 6,900 illegal drug listings across social media platforms and marketplaces in total, including 992 marketplaces in India, 544 in Indonesia, 364 in China and 114 in Brazil.

Keren said the company did not have data on how many of these social media listings and marketplaces were selling fake versions of GLP-1s.

(Reporting by Patrick Wingrove in New York; Editing by Caroline Humer and Aurora Ellis)