SHANGHAI (Reuters) -Novo Nordisk said on Tuesday its popular weight-loss drug Wegovy has been approved in China, paving the way for sales in the world's second-largest economy.

Novo said in March that it would initially target Chinese patients willing to pay out-of-pocket for the weekly injectable drug.

The company did not immediately respond to a Reuters request for comment on when sales will begin, how the drug will be priced and how much it intends to ship to China.

Novo may have a much shorter time in the Chinese market to make the most of its early-mover advantage in weight-loss drugs.

Its patent on semaglutide, the key ingredient used in Wegovy and its diabetes drug Ozempic, is set to expire in less than two years in China and local drugmakers are racing to develop generic versions.

In contrast, the patent will expire in 2031 in Europe and Japan and in 2032 in the United States.

Novo also faces competition from rival Eli Lilly, whose diabetes drug tirzepatide received approval from China in May. Some analysts expect Zepound, the U.S. firm's weight-loss drug with the same active ingredient, will be approved in China this year or in the first half of 2025.

The number of adults who are overweight in China is projected to reach 540 million by 2030, a rise of 2.8 times from 2000 levels, while those who are obese are expected to jump 7.5 times to 150 million, according to a 2020 study by Chinese public health researchers.

Ozempic won approval from China in 2021 and Novo saw sales of the drug in the greater China region double to 4.8 billion Danish crowns ($698 million) last year.