COPENHAGEN, DENMARK (Reuters) -Shares in Novo Nordisk rose on Monday, after it got U.S. approval for its weight-loss drug Wegovy to treat a serious liver condition, positive news for the drugmaker that lost more than one-third of its market value in recent weeks.

Novo's shares rose as much as 5% at opening and were trading 3.5% higher by 0711 GMT.

Three weeks ago, investors wiped $70 billion off its market value, after Novo - which became Europe's most valuable listed company following the launch of Wegovy in 2021 - issued a profit warning and named a company veteran as new CEO. 

On Friday, the U.S. Food and Drug Administration granted accelerated approval for Wegovy to treat metabolic dysfunction-associated steatohepatitis, or MASH, making it the first GLP-1 class therapy cleared for the progressive liver condition that affects around 5% of adults in the United States.

Rival Eli Lilly has published encouraging MASH data in a mid-stage trial with tirzepatide - the active ingredient in its popular diabetes drug Mounjaro and weight-loss treatment Zepbound.

"It is expected that this market exclusivity will only last for a transitional phase before Eli Lilly also launches a product on the market," said Nordnet analyst Per Hansen. 

Novo has also applied this year for approval in Europe and Japan. 

Its shares have lost more than two-thirds of their value since June last year, amid concerns that the Danish drugmaker is losing ground in the obesity drug race it started to rival Eli Lilly and "compounded" copycat drugs.

(Reporting by Jacob Gronholt-Pedersen and Elviira Luoma; Editing by Emelia Sithole-Matarise)