Pharma BD Deal Intelligence

Merck & Co. Inc. / Harpoon Therapeutics

2024 · Acquisition/Merger · $680M · Complete

CALLED IT — OFF BY 18
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The coverage arc

Mar 12, 2024 Pharmaceutical Technology Bullish

Merck completes acquisition of Harpoon Therapeutics adding T-cell engager portfolio to diversify beyond checkpoint inhibitor Keytruda

Dec 31, 2025 Merck Bullish

Merck completes acquisition of Harpoon Therapeutics broadening oncology pipeline with novel T-cell engager programs including HPN328

Feb 24, 2026 ClinicalTrials.gov NCT04471727 Neutral

MK-6070 / HPN328 (gocatamig), DLL3-targeting T-cell engager. Phase 1/2, ACTIVE_NOT_RECRUITING (last update 2026-02-24). Conditions: small cell lung cancer,…

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Merck (NYSE: MRK) acquired Harpoon Therapeutics for $23.00 per share, or approximately $680 million, in a cash tender offer announced January 8, 2024 and completed March 11, 2024. The strategic rationale was Harpoon's lead T-cell engager HPN328 (subsequently renamed MK-6070, INN gocatamig), a DLL3-targeting TriTAC for small cell lung cancer and other high-grade neuroendocrine tumors. Post-close, Merck moved quickly to share the asset's risk and cost: on August 6, 2024 Daiichi Sankyo and Merck entered a global co-development and co-commercialization agreement for MK-6070, under which Merck received a $170 million upfront payment and the companies share R&D and commercialization expenses and profits worldwide except Japan, where Merck retains exclusive rights. MK-6070 remains in the Phase 1/2 trial NCT04471727 (active, not recruiting as of February 2026), evaluated as monotherapy and in combination with atezolizumab and with ifinatamab deruxtecan (I-DXd) in SCLC.

Key facts

Related deals — scored

DealYearValueOutcome
Merck & Co. Inc. / Harpoon Therapeutics (this deal)2024$680M65
Merck & Co. Inc. / Acceleron Pharma Inc.2021$11.5B90
Merck & Co. Inc. / Peloton Therapeutics Inc.2019$2.2B88
Merck & Co. Inc. / AstraZeneca PLC2017$8.5B87
Merck & Co. Inc. / Moderna, Inc.2022$250M86
Merck & Co. Inc. / Moderna, Inc.2016$250M84
Merck & Co. Inc. / Eisai Co., Ltd.2018$5.8B83

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