Pharma BD Deal Intelligence
Merck's $680M cash-tender takeout of Harpoon looks like a smart bolt-on: the entire rationale rode on one DLL3 T-cell engager, HPN328/MK-6070, and within seven months Merck had already de-risked it by handing Daiichi Sankyo global co-development rights for a $170M upfront. The asset is still mid-Phase 1/2 in small cell lung cancer with no efficacy readout yet, so this remains a slow-burn bet rather than a proven win.
Merck completes acquisition of Harpoon Therapeutics adding T-cell engager portfolio to diversify beyond checkpoint inhibitor Keytruda
Merck completes acquisition of Harpoon Therapeutics broadening oncology pipeline with novel T-cell engager programs including HPN328
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.
35K US cases/yr · $4.5B Global SCLC + NET Market (2025E)
HPN328/MK-6070 is a DLL3-targeting TriTAC T-cell engager for SCLC and NETs. Positive interim tolerability/response data. Also studying combo with atezolizumab.
AbbVie Imdelltra (tarlatamab) is FDA-approved DLL3xCD3 for SCLC. MK-6070 TriTAC format is differentiated.
Merck & Co. Inc. completed a acquisition/merger transaction with Harpoon Therapeutics.
On August 6, 2024 Daiichi Sankyo and Merck entered a global co-development and co-commercialization agreement for MK-6070 (the DLL3 T-cell engager Merck acquired with Harpoon). Merck received a $170 million upfront payment; the companies share R&D and commercialization expenses and profits worldwide except Japan, where Merck retains exclusive rights.
Significant transaction at $680M. Merck acquired Harpoon Therapeutics for $680M for T-cell activator HPN328.
| Deal | Year | Value | Outcome |
|---|---|---|---|
| Merck & Co. Inc. / Harpoon Therapeutics (this deal) | 2024 | $680M | 65 |
| Merck & Co. Inc. / Acceleron Pharma Inc. | 2021 | $11.5B | 90 |
| Merck & Co. Inc. / Peloton Therapeutics Inc. | 2019 | $2.2B | 88 |
| Merck & Co. Inc. / AstraZeneca PLC | 2017 | $8.5B | 87 |
| Merck & Co. Inc. / Moderna, Inc. | 2022 | $250M | 86 |
| Merck & Co. Inc. / Moderna, Inc. | 2016 | $250M | 84 |
| Merck & Co. Inc. / Eisai Co., Ltd. | 2018 | $5.8B | 83 |
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