Harpoon Therapeutics
Harpoon Therapeutics is a clinical-stage immunotherapy company developing proprietary trispecific T-cell engager (TriTAC) therapies for solid tumors, with lead candidate HPN328 in Phase 1/2 trials for small cell lung cancer and neuroendocrine tumors. Acquired by Merck for $680 million in 2024.
- Company typePrivate
- Founded2015
- HeadquartersSouth San Francisco, United States
- Headcount51–100
- GTM typeB2B
- OfferingHardware or Manufacturing
What Harpoon Therapeutics does
Harpoon Therapeutics is a clinical-stage immunotherapy company that develops novel T-cell engaging biologic therapies for cancer, headquartered in South San Francisco and operating with 51-100 employees. The company's core technology is its proprietary TriTAC (Trispecific T-cell Activator) platform, which engineers trispecific antibodies designed to redirect T-cells to recognize and destroy cancer cells. Its lead clinical candidate, HPN328, was in Phase 1/2 trials for small cell lung cancer and neuroendocrine tumors and demonstrated 40% disease control rates in heavily pretreated patients. The pipeline focuses on immuno-oncology applications where conventional therapies have produced limited durable responses.
Harpoon operated as a pre-revenue clinical-stage biotech with no commercialized products or disclosed pricing; its revenue model relied on future commercialization of approved therapies, supplemented by licensing and partnership economics. The company raised capital through multiple private placements from specialist biotech investors including New Leaf Venture Partners, Arix Bioscience, OrbiMed, Invus, K2 HealthVentures, and MPM Capital, including a $25M round in March 2023 and a placement of up to $150M announced in October 2023. The company pursued a NASDAQ IPO (ticker HARP) and ultimately was acquired by Merck & Co. in 2024 for $680 million, after which it operates as a wholly-owned subsidiary folded into Merck's immuno-oncology franchise.
The company's customer base is entirely future-facing: it targets heavily pretreated oncology patients with limited therapeutic options, and its go-to-market relies on pharmaceutical partnerships and large-pharma M&A rather than direct sales. Distribution would flow through specialty pharmacies, hospital formularies, and oncology treatment centers upon approval. Scientific and corporate communications are conducted through SEC filings, investor relations, and clinical-trial publications rather than traditional marketing channels.
Harpoon Therapeutics firmographics
Firmographics- Name
- Harpoon Therapeutics
- Legal name
- Harpoon Therapeutics
- Website
- https://harpoontx.com
- Company type
- Private
- Founded year
- 2015
- Operating status
- Acquired
- Headcount range
- 51–100 employees
- Short description
- Harpoon Therapeutics is a clinical-stage immunotherapy company developing proprietary trispecific T-cell engager (TriTAC) therapies for solid tumors, with lead candidate HPN328 in Phase 1/2 trials for small cell lung cancer and neuroendocrine tumors. Acquired by Merck for $680 million in 2024.
- Ownership category
- akta.pro rank
Harpoon Therapeutics industry classification
Industry- Product category
- Cancer Immunotherapy / Oncology Biologics
- NAICS
- Biological Product (except Diagnostic) Manufacturing (325414), Research and Development in Biotechnology (except Nanobiotechnology) (541714), Scientific Research and Development Services (5417)
- SIC
- Pharmaceutical Preparations (2834), Services-Commercial Physical & Biological Research (8731)
- akta.pro primary industry
- Bispecific & Multispecific Antibodies (HLAAAAAF)
- akta.pro secondary industries
- CAR-T & TCR-T Therapies (HLAAABAC), Cell Therapy Enabling Technologies (gene editing, cell engineering, delivery methods) (HLAAABAL)
Keywords
Where Harpoon Therapeutics is headquartered
LocationHeadquarters
- HQ city
- South San Francisco
- HQ country
- United States
- HQ region
- North America
Markets served
Harpoon Therapeutics business model
Business model- GTM type
- B2B
- Offering type
- Hardware or Manufacturing
- Cost components
- Technology or R&D, Personnel, Operations
Revenue model
- Drug Development and Commercialization: Pre-revenue clinical-stage biotech company. Revenue potential through commercialization of proprietary T-cell engager therapies upon regulatory approval. Lead candidate HPN328 projected to exceed $1 billion peak sales if approved.
- M&A / Acquisition: Company was acquired by Merck & Co. for $680 million to enhance Merck's immuno-oncology portfolio.
Go-to-market motion1 record
Marketing channels1 record
Harpoon Therapeutics product offering
Product offeringCore offering
Harpoon Therapeutics is a clinical-stage immunotherapy company developing T-cell engager cancer therapies built on its proprietary TriTAC (Trispecific T-cell Activator) platform — a trispecific antibody-based technology that redirects T-cells to target and destroy cancer cells. The company's lead clinical candidate, HPN328, is being evaluated in Phase 1/2 trials for small cell lung cancer and neuroendocrine tumors. Harpoon had no commercialized products and operated as a pre-revenue development-stage biotech prior to its acquisition by Merck & Co.
Product overview
Harpoon Therapeutics is a clinical-stage immunotherapy company developing a proprietary TriTAC platform for T-cell engager cancer therapies. The platform enables trispecific antibody development. Lead candidate HPN328 is in Phase 1/2 trials for small cell lung cancer and neuroendocrine tumors. The company's pipeline focuses on immuno-oncology applications.
Differentiator
Problem solved
Functional benefit
Products and services
- TriTAC Platform Proprietary trispecific antibody-based technology platform that enables development of T-cell engager cancer therapies by redirecting T-cells to target and destroy cancer cells; used internally by Harpoon to build its oncology pipeline and acquired by Merck & Co. as part of the 2024 acquisition to bolster immuno-oncology R&D.
- HPN328 Lead clinical-stage T-cell engager drug candidate from the TriTAC platform, in Phase 1/2 trials for small cell lung cancer and neuroendocrine tumors, with reported 40% disease control rates in heavily pretreated patients; intended for eventual regulatory approval and commercialization in oncology indications with high unmet need.
Quantifiable outcome
- HPN328 demonstrated 40% disease control rates in heavily pretreated patients
Companies that use Harpoon Therapeutics
Customer profileSegments1 record
Ideal customer profiles2 records
Harpoon Therapeutics technology and API
TechnologyTechnology focussed Yes
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature1 record
Harpoon Therapeutics partnerships and signals
Strategic signalPartnerships
One partnership is on record.
- Merck & Co.coreMerck & Co. completed a $680 million acquisition of Harpoon Therapeutics to enhance its immuno-oncology portfolio. The acquisition provides Merck access to Harpoon's TriTAC platform for T-cell engager cancer therapies and lead candidate HPN328.
Scale indicators5 records
Recent moves6 records
Expansion highlights4 records
Harpoon Therapeutics competitors and assessment
Company assessmentDirect peers
- Maverick Therapeutics: Develops T-cell engager immunotherapies (COBRA platform) for solid tumors — closely comparable modality and oncology focus to Harpoon Therapeutics.
- MacroGenics: Clinical and commercial-stage oncology biotech with multiple bispecific antibody programs (e.g., DART platform), including T-cell engagers — directly comparable modality and indication strategy.
- Janux Therapeutics: Clinical-stage oncology company developing T-cell engager therapies (TRACTr platform) for solid tumors — directly comparable to Harpoon's TriTAC modality and target indications.
- Xencor: Clinical-stage biotech engineering bispecific and multispecific antibody therapeutics for cancer and autoimmune disease — overlapping T-cell engager and immuno-oncology development focus.
- Cullinan Therapeutics: Clinical-stage biopharmaceutical company developing immuno-oncology therapies including T-cell engagers and bispecific antibodies for cancer — overlapping modality and target space.
Emerging players
- CytomX Therapeutics: Clinical-stage oncology company developing Probody therapeutics, a conditionally activated antibody platform — comparable biologics-based immuno-oncology approach with T-cell engager candidates in pipeline.
- Adagene: Clinical-stage biotech developing bispecific antibodies (POWER and SAFE platforms) for solid tumors — comparable modality with T-cell engager programs targeting oncology.
- Bolt Biotherapeutics: Clinical-stage immuno-oncology company developing bispecific immune-stimulating antibody conjugates (ISACs) — adjacent immuno-oncology approach with comparable oncology indication focus.
Broad incumbents
- Regeneron (Bispecific Programs): Large commercial-stage biopharmaceutical with bispecific antibody programs (e.g., linvoseltamab, odronextamab) — broader oncology portfolio with overlapping T-cell engager modality and target indications.
- Genmab: Commercial-stage antibody company with the proprietary DuoBody bispecific platform — established player in bispecific/multispecific antibody-based cancer therapeutics broadly comparable to TriTAC.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat2 records
Key risks6 records
Key highlights6 records
Customer concentration
Harpoon Therapeutics social profiles
Digital presenceHarpoon Therapeutics financial estimates
Financial estimateRevenue estimate
Valuation estimate
Harpoon Therapeutics leadership team
Management profileNumber of profiles
Profiles7 records
Harpoon Therapeutics funding detail
Funding detailFunding overview
Funding rounds5 records
Investors19 records
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Harpoon Therapeutics M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Harpoon Therapeutics
What does Harpoon Therapeutics do?
Harpoon Therapeutics is a clinical-stage immunotherapy company developing T-cell engager cancer therapies built on its proprietary TriTAC (Trispecific T-cell Activator) platform — a trispecific antibody-based technology that redirects T-cells to target and destroy cancer cells. The company's lead clinical candidate, HPN328, is being evaluated in Phase 1/2 trials for small cell lung cancer and neuroendocrine tumors. Harpoon had no commercialized products and operated as a pre-revenue development-stage biotech prior to its acquisition by Merck & Co.
Is Harpoon Therapeutics a public or private company?
Harpoon Therapeutics is a private company. It is classified as corporate owned and is currently acquired.
When was Harpoon Therapeutics founded?
Harpoon Therapeutics was founded in 2015. It employs 51 to 100 people.
Where is Harpoon Therapeutics based?
Harpoon Therapeutics is headquartered in South San Francisco, United States, in the North America region.
How does Harpoon Therapeutics make money?
Two revenue lines are on record. Drug Development and Commercialization is the primary driver. The others are M&A / Acquisition.
Who are Harpoon Therapeutics's main competitors?
Direct peers on record are Maverick Therapeutics, MacroGenics, Janux Therapeutics, Xencor and Cullinan Therapeutics. Emerging players are CytomX Therapeutics, Adagene and Bolt Biotherapeutics. Broad incumbents are Regeneron (Bispecific Programs) and Genmab.
Does Harpoon Therapeutics have an API?
No public API is recorded for Harpoon Therapeutics.
What industry is Harpoon Therapeutics in?
Harpoon Therapeutics's product category is Cancer Immunotherapy / Oncology Biologics. Its primary akta.pro industry code is HLAAAAAF, Bispecific & Multispecific Antibodies, with a secondary code of HLAAABAC, CAR-T & TCR-T Therapies. Its NAICS code is 325414 and its SIC code is 2834.