Merck & Co. posted higher third-quarter revenue Thursday, as growth from its blockbuster cancer drug Keytruda offset falling sales from human papillomavirus vaccine Gardasil in China.

However, shares fell 3% premarket after Merck narrowed its revenue guidance for the full year. It now expects revenue of $64.5 billion to $65.0 billion compared with its prior forecast of $64.3 billion to $65.3 billion.

Shares of Merck have fallen about 5% so far in 2025, as investors weigh the company's efforts to grow beyond Keytruda against broader industry headwinds, including potential U.S. drug pricing reforms.

Merck is working to add new drugs to its pipeline before Keytruda, which accounts for over 47% of its total sales, faces competition from cheaper biosimilars later this decade.

The company posted revenue of $17.28 billion in the quarter, compared with analyst estimates of $16.96 billion, according to data compiled by LSEG.

On an adjusted basis, the company earned $2.58 per share, compared with estimates of $2.35 per share

Sales of Keytruda rose 10% to $8.1 billion in the quarter, in line with analysts' estimates. Gardasil sales fell to $1.75 billion, ahead of the Wall Street forecast of $1.66 billion.

The company has not been making new shipments of the vaccine to China. It has said distributors there are working through their inventories after a fall in demand due to pressure on consumer spending in the country.

Merck said it expects full-year earnings of $8.93 to $8.98 a share, compared with its forecast of $8.87 to $8.97 previously.