(Bloomberg) -- More than $6.4 billion in health-care deals were announced on Monday as the annual JPMorgan Healthcare Conference kicked off in San Francisco. 

The deals include Merck & Co.’s $680 million purchase of cancer drugmaker Harpoon Therapeutics Inc., Boston Scientific Corp.’s $3.7 billion acquisition of device-maker Axonics Inc. and Johnson & Johnson’s $2 billion deal to buy Ambrx Biopharma Inc., whose therapies target tumors with lethal drugs.

Big pharma has been looking to acquisitions to replace blockbusters that are losing steam. Patents are facing looming expiration dates and demand has slowed for once-popular Covid vaccines and treatments. The industry is also sweating government price negotiations under US President Joe Biden’s Inflation Reduction Act.

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The end of 2023 brought a frenzy of biotech deals, with weight-loss drug companies and targeted cancer treatments in the highest demand. Harpoon Therapeutics, for example, is developing drugs that harness the body’s immune system to fight cancer, while Ambrx Biopharma is developing antibody-drug conjugates that deliver high doses of drugs directly to tumors. 

In some cases, drugmakers are paying more than double a company’s stock price to secure promising therapies. It’s a big reversal from a year ago, when pharmaceutical companies were laying off employees and cutting costs. 

Investors had a mixed response to Monday’s deals. The acquirers were little changed, while the target companies surged. Harpoon Therapeutics and Ambrx Biopharma were up by more than 100% in trading on Monday. Axonics was up by as much as 21%. 

Still, expectations for big acquisitions remains high. Cytokinetics Inc. fell by as much as 8.4% Monday after it wasn’t included in the slew of deal announcements. The company, which develops cardiovascular treatments, has been courting buyers since last fall, according to Bloomberg News reports. 

XBI, a closely watched ETF that tracks biotech companies, was little changed Monday. That’s likely because the deals weren’t “particularly large” or for the “the more heavily speculated on bigger ticket names that investors were watching and hoping for,” said Bloomberg Intelligence analyst Max Nisen. 

--With assistance from Nacha Cattan.

(Updates with more information on Harpoon Therapeutics and Ambrx Biopharma in the fourth paragraph. An earlier version of this story corrected company name in the 5th paragraph.)

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