Harpoon Therapeutics is a technology company.
Harpoon Therapeutics has raised $115.0M across 2 funding rounds.
Harpoon Therapeutics has raised $115.0M in total across 2 funding rounds.
Harpoon Therapeutics is a clinical-stage immunotherapy company developing T cell engagers—engineered proteins that direct patients' T cells to kill cancer cells expressing specific antigens—primarily targeting solid tumors and hematologic malignancies like small cell lung cancer (SCLC) and multiple myeloma.[1][2][3] Its proprietary platforms include the TriTAC (tri-specific T cell activating construct) for immune activation, ProTriTAC (a prodrug version that activates only at tumors), and TriTAC-XR (to reduce cytokine release syndrome).[2][3][4] Key candidates serve oncology patients with advanced cancers: lead asset HPN328 (now MK-6070 post-acquisition) targets DLL3 in SCLC and neuroendocrine tumors (Phase 1/2 trials); HPN217 targets BCMA in multiple myeloma (Phase 1); and preclinical HPN601 targets EpCAM in solid tumors.[1][3][5] The company addressed unmet needs in hard-to-treat cancers but was acquired by Merck in March 2024 for ~$650-680M, integrating its pipeline into Merck's oncology efforts amid Keytruda patent cliffs.[6][7]
Founded in 2015 and headquartered in South San Francisco, California, Harpoon Therapeutics emerged from innovations in T cell engager technology to harness the immune system against cancer.[1][2] While specific founders are not detailed in available sources, the company quickly advanced its TriTAC platform, securing a discovery collaboration with AbbVie for soluble T cell receptor integration.[1] Early traction included advancing HPN328 into Phase 1/2 trials (NCT04471727) showing 48% tumor shrinkage in SCLC patients, despite pauses for cytokine issues like respiratory failure in neuroendocrine trials (later revised).[3][6] Pivotal growth led to Merck's acquisition in early 2024, valuing its bispecific tech amid rising demand for next-gen immunotherapies beyond blood cancers.[5][6][7]
Harpoon stood out in immuno-oncology through targeted platforms optimizing T cell engagement:
These features differentiated Harpoon from traditional bispecifics, prioritizing solid tumor penetration and tolerability.[6]
Harpoon rode the bispecific T cell engager wave, extending blood cancer successes (e.g., approved bispecifics) to solid tumors amid immunotherapy evolution post-PD-1 dominance like Keytruda.[3][6] Timing aligned with 2020s urgency: SCLC's poor prognosis (chemo/Tecentriq standards) and DLL3's promise after AbbVie’s ADC failure made HPN328 compelling, with 48% response rates fueling interest.[6] Market forces favoring it included Big Pharma's pipeline diversification—Merck's $680M buyout countered Keytruda's 2028 exclusivity loss, blending Harpoon's tech with Keytruda combos.[5][6][7] Harpoon influenced the ecosystem by validating prodrug and CRS-mitigating platforms, accelerating T cell therapies for antigen-rich solids and inspiring rivals in immuno-oncology.[2][3]
Post-2024 Merck acquisition, Harpoon's assets like MK-6070 (HPN328) advance in Phase 1/2 for DLL3+ cancers, potentially combining with Keytruda to sustain Merck's dominance.[3][6][7] Trends shaping it include bispecific maturation for solids, AI-driven antigen discovery, and CRS solutions enabling broader adoption.[2][6] Influence evolves via Merck's scale: faster trials, global reach, and pipeline integration could yield approvals by late 2020s, transforming SCLC treatment while validating Harpoon's immune-harnessing vision from a nimble biotech to pharma powerhouse.[1][5]
Harpoon Therapeutics has raised $115.0M in total across 2 funding rounds.
Harpoon Therapeutics's investors include Arix Bioscience, Canaan Partners, Amplitude VC, MPM Capital, Venrock.
Harpoon Therapeutics has raised $115.0M across 2 funding rounds. Most recently, it raised $70.0M Series C in November 2018.
| Date | Round | Lead Investors | Other Investors |
|---|---|---|---|
| Nov 1, 2018 | $70.0M Series C | Arix Bioscience, Canaan Partners | |
| May 1, 2017 | $45.0M Series B | Amplitude VC, Arix Bioscience, Canaan Partners, MPM Capital, Venrock |