Dec 13 (Reuters) - Pfizer on Wednesday forecast 2024 sales that could be as much as $5 billion below Wall Street expectations, a move top executives said provided a more reliable view of its COVID-19 business than it had this year, driving shares to a 10-year low.

Revenue from Pfizer's COVID-19 vaccine and treatment, which peaked at $57 billion in 2022, are now expected to be $8 billion in 2024, a further drop from the $13 billion analysts' forecast and Pfizer's own lowered view of $12.5 billion for this year.

"We want to be conservative," Pfizer Chief Executive Officer Albert Bourla said on a conference call with investors. "We want to be reliable so we won't create uncertainty (again), which was the case, unfortunately, this year."

Pfizer used some of its COVID windfall to acquire companies, including a $43 billion deal for cancer drugmaker Seagen it expects to close this week, and began selling a new RSV vaccine. But the recent RSV launch has been disappointing, trailing a rival's shot, and shares have fallen 44% so far this year.

In addition, COVID vaccinations in the U.S. have dropped sharply with just about 17% of the eligible population getting the most recent updated boosters due in part to declining concern about the virus, as well as vaccine fatigue.

The New York-based drugmaker also forecast 2024 adjusted profit in the range of $2.05 to $2.25 per share, lower than analysts' expectation of $3.16.

Pfizer shares closed down another 6.7% on Wednesday, losing nearly $11 billion in market capitalization.

U.S. shares of Pfizer's German vaccine partner BioNTech fell 5.5%, while COVID vaccine rival Moderna rose 0.7%.

"They're in a bad place honestly," said Jeff Jonas, portfolio manager for Gabelli Funds, which owned over 750,000 Pfizer shares as of September, according to LSEG data.

Jonas said the company has taken on a lot of debt to do deals like Seagen. But he is skeptical the company has done enough to fully offset lost revenue from drugs expected to face generic competition in coming year.

"They're stuck in their ways and then they're not necessarily going to make the type of bold move that they need to reinvigorate R&D," Jonas said of research and development.

Seagen is expected to add $3.1 billion to revenue next year.

'A FLOOR FOR 2024 SALES'

The lower forecasts come a day after Pfizer said it would reorganize its cancer division to include the Seagen acquisition. It also raised its cost-cut target by $500 million on Wednesday.

Pfizer now expects annual revenue in the range of $58.5 billion to $61.5 billion, compared with analysts' average estimate of $63.17 billion, according to LSEG data.

The COVID-19 vaccine and antiviral treatment Paxlovid helped Pfizer bring in over $100 billion in revenue in 2022. Pfizer had originally forecast sales of $21.5 million in COVID sales for 2023, but later cut that forecast by more than 40%.

The COVID-19 sales targets "likely represent a floor for 2024 sales," said J.P. Morgan analyst Chris Schott.

The precipitous drop in COVID product sales had also forced Pfizer to launch a program to cut jobs and expenses, which is now expected to save at least $4 billion a year by the end of 2024.

Pfizer said on Tuesday that Chief Commercial Officer Angela Hwang would step down, and the company would reorganize its commercial business, not including oncology, into two divisions, one focused on the United States and the other on the rest of the world.

Citi analyst Andrew Baum said Pfizer's management is acting with increasing urgency to address its weak stock performance. However, the absence of promising high-potential pipeline assets makes it difficult for the company with several Pfizer products expected to go off patent in the next few years.

(Reporting by Leroy Leo in Bengaluru; Editing by Nick Zieminski and Bill Berkrot)