MRK Merck and Co Inc

By Colin Kellaher

Merck & Co. has struck a deal to buy clinical-stage immunotherapy company Harpoon Therapeutics for about $680 million.

Merck on Monday said it will pay $23 a share in cash for Harpoon, more than double Friday's closing price of $10.55 for the South San Francisco, Calif., company.

Bloomberg earlier reported that Rahway, N.J.-based Merck was in talks to buy Harpoon.

Merck said the deal adds Harpoon's HPN328, which is being evaluated in certain patients with small cell lung cancer and neuroendocrine tumors.

Merck, which is girding for the pending 2028 loss of patent protection for its blockbuster cancer drug Keytruda, said it expects to complete the Harpoon acquisition in the first half of the year, adding that the deal will result in a charge of about $650 million, or 26 cents a share.

Harpoon shares were recently up about 110% to $22.11 in premarket trading.

Write to Colin Kellaher at colin.kellaher@wsj.com

(END) Dow Jones Newswires

January 08, 2024 07:57 ET (12:57 GMT)

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