March 15 (Reuters) - Eli Lilly's ( LLY ) powerful

weight-loss drug Zepbound hit 77,590 new prescriptions in the

U.S. for the week ending March 8, surpassing Novo Nordisk's

rival obesity medicine Wegovy for the first time

since it was launched, according to data from IQVIA ( IQV ).

Some 6,000 fewer Wegovy prescriptions were filled in the

United States that week, but Novo maintained its lead for total

weekly prescriptions over Zepbound by 25,307, according to the

data published by JPMorgan in a weekly note.

Novo, Lilly and IQVIA ( IQV ) did not immediately respond to

requests for comment.

Lilly launched Zepbound in the U.S. in December, more than

two years after Wegovy's approval in June 2021.

Shares of Lilly and Novo were off about 1% and 2%,

respectively on a down day for the broader market.

At stake in the competition for new patients looking to lose

weight is a market analysts' see reaching at least $100 billion

by the end of the decade. Demand so far has well outpaced

supplies, as consumers flock to new treatments that have been

shown to reduce weight by as much as 20%.

Zepbound and Wegovy belong to a class of drugs called GLP-1

agonists developed for type 2 diabetes that also reduce food

cravings and cause the stomach to empty more slowly.

Data analytics firm GlobalData in a report on Friday said

GLP-1 drugs are on pace to this year surpass widely used cancer

immunotherapies as the best-selling medicines, driven by trial

data showing they can also treat other health conditions, and a

surge in celebrity and influencer endorsements. Merck and Co's ( MRK )

cancer drug Keytruda is currently the world's

top-selling prescription medicine with over $25 billion in

annual sales.

The U.S. Food and Drug Administration last week approved

Wegovy for lowering the risk of stroke and heart attack in

overweight or obese adults who do not have diabetes.

GlobalData forecast the market for these medicines reaching

$105 billion by 2029, and that Novo Nordisk would capture more

than half of that with its portfolio of GLP-1 drugs, including

Wegovy.

The Danish drugmaker last week said it was confident it

would launch a pill version of its experimental weight-loss drug

amycretin this decade. Currently GLP-1 drugs are injected.

Lilly's diabetes drug Mounjaro, which has the same active

ingredient as Zepbound, will be the top-selling GLP-1 with $33.4

billion in annual sales by 2029, GlobalData forecast.

Lilly this week said it has partnered with Amazon.com's ( AMZN )

pharmacy unit to deliver drug prescriptions sent to its

direct-to-consumer service LillyDirect, including those for

Zepbound.

Frank Cunningham, an executive at Lilly, said the company

was "very pleased" with the number of prescriptions it had

filled through LillyDirect so far.