Aug 14 (Reuters) - Eli Lilly ( LLY ) has sent

cease-and-desist letters to U.S. healthcare providers in recent

days to stop the promotion of the compounded versions of its

drugs for weight loss and diabetes, as their supply increases,

the company said on Wednesday.

The letters were sent to telehealth companies, wellness

centers and medical spas selling compounded versions of the

drugmaker's popular treatments Zepbound and Mounjaro, a

spokesperson told Reuters.

"When FDA-approved medicines are 'commercially

available', compounders cannot regularly make 'essentially a

copy' of them," the company said in its emailed statement.

Compounded drugs are custom-made medicines that are based on

the same ingredients as branded drugs. Because Zepbound and

Mounjaro, both known chemically as tirzepatide, were in short

supply, they could be legally produced by licensed pharmacies in

the U.S.

However, surging demand for Lilly and Danish rival Novo

Nordisk's weight-loss drugs, which can cost more than

$1,000 for a month's supply, has prompted numerous sellers to

offer compounded versions at lower prices.

Lilly and Novo have previously sued more than three dozen

medical spas, weight-loss clinics, compounding pharmacies and

online sellers in total to stop them from selling products

claiming to contain the active ingredients in their drugs.

The U.S. Food and Drug Administration has listed all doses

of Lilly's drugs as available but has not removed them from the

shortage list.

The FDA said in an emailed response that it was currently

working to determine if the available supply of tirzepatide, the

active ingredient in Mounjaro and Zepbound, would meet its

definition of a resolved shortage.

Last month, the FDA

warned

patients and doctors about dosing errors associated with

compounded versions of Novo Nordisk's weight loss and diabetes

drugs.

The health regulator said it had received reports of

adverse events, some requiring hospitalization, that may be

related to overdoses due to patients incorrectly

self-administering the compounded drug and healthcare providers

miscalculating doses.