OS Therapies

Name

OS Therapies

Legal name

OS Therapies, Inc.

Website

https://ostherapies.com

Company type

Public

Founded year

2018

Operating status

Operating

Headcount range

11–50 employees

Ownership category

akta.pro rank

Product category

Cancer Immunotherapy / Oncology Biologics

NAICS

Biological Product (except Diagnostic) Manufacturing (325414)

SIC

Pharmaceutical Preparations (2834)

akta.pro primary industry

Oncology Gene Therapies (incl. oncolytic vectors & gene-modified approaches) (HLAAACAF)

Keywords

• Cancer immunotherapy
• Osteosarcoma treatment
• HER2 targeted therapy
• Antibody drug conjugates
• Clinical-stage biopharmaceuticals

Headquarters

HQ city

Rockville

HQ country

United States

HQ region

North America

Offices3 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations, Marketing or Sales, Others

Revenue model

1. Future OST-HER2 product sales: Pre-revenue clinical-stage company planning commercialization of OST-HER2 in recurrent, fully resected, pulmonary metastatic osteosarcoma across U.S., U.K., Europe, and Australia. Forecasted peak European sales exceed $300 million annually, with over $50 million in sales expected as early as 2027.
2. Priority Review Voucher (PRV) monetization: If OST-HER2 receives Rare Pediatric Disease BLA approval, OS Therapies becomes eligible to receive a Priority Review Voucher; the most recent publicly disclosed PRV transaction was valued at $205 million in February 2026, and the company has stated it intends to sell any PRV granted.
3. OS Animal Health (spinoff) revenue stream: OS Therapies announced the planned spinoff of subsidiary OS Animal Health into a standalone public company in the first half of 2026, targeting the canine osteosarcoma treatment market, which is part of the broader veterinary oncology market projected to reach $4.77 billion by 2034.
4. Non-dilutive funding (VAT refunds / R&D tax credits): Non-revenue cash inflows from U.K. subsidiary VAT refunds and R&D tax credits; expected to total approximately $4 million, with $2 million in VAT refunds anticipated in June 2026. Supports operations without diluting shareholders.

Pricing tiers

Go-to-market motion3 records

Distribution channels4 records

Marketing channels7 records

Core offering

OS Therapies is a clinical-stage oncology biopharmaceutical company developing OST-HER2 (daznelimgene lisbac), a gene-edited Listeria monocytogenes cancer immunotherapy that activates HER2-specific killer T cells against HER2-expressing tumors, beginning with recurrent, fully resected, pulmonary metastatic osteosarcoma. Its second platform is OST-tADC, a Tunable Antibody-Drug Conjugate platform built on a proprietary silicone-based SiLinker and Conditionally Active Payloads that release cell-penetrating toxins in acidic tumor microenvironments to reduce systemic toxicity. Both programs are intended for licensing and commercialization to enterprise hospital systems and specialty oncology centers across the U.S., U.K., Europe, and Australia.

Product overview

OS Therapies is a clinical-stage cancer immunotherapy company that operates a platform-plus-pipeline architecture centered on a proprietary listeria-based vector technology. Its core lead product, OST-HER2 (also known as OST31-164 / daznelimgene lisbac), is a HER2-targeted listeria immunotherapy being advanced through a Phase 2b trial (AOST-2121) and a planned global confirmatory Phase 3 trial for recurrent, fully resected, pulmonary metastatic osteosarcoma, with planned label expansion into breast, esophageal, lung, ovarian, and pancreatic cancers. Layered on top of this lead asset is the OST-tADC (Tunable Drug Conjugates) ADC platform, which uses pH-sensitive SiLinkers and Conditionally Active Payloads (CAPs) to improve tumor-specific drug delivery. A third asset, the OS Animal Health subsidiary, extends the listeria-based OST-HER2 immunotherapy into canine osteosarcoma and is planned to be spun off as a standalone public company. Together, these products form a coordinated portfolio combining HER2-targeted cancer immunotherapy, a tunable ADC platform, and a veterinary spin-out.

Differentiator

Problem solved

Functional benefit

Brands

• OST-HER2: Lead listeria-based immunotherapy product candidate (daznelimgene lisbac) targeting osteosarcoma in recurrent, fully-resected, pulmonary metastatic setting.
• OST-tADC
• OS Animal Health

Products and services

• OST-HER2 (daznelimgene lisbac / OST31-164) OS Therapies' lead clinical-stage immunotherapy that uses a gene-edited Listeria monocytogenes vector to deliver HER2 antigens and activate HER2-specific killer T cells against HER2-expressing cancers. It is being developed to prevent or delay recurrent, fully resected, pulmonary metastatic osteosarcoma, with planned expansion into breast, esophageal, lung, ovarian, and pancreatic cancers. Received FDA Orphan Drug, Fast Track, and Rare Pediatric Disease designations, EMA Fast Track and ATMP, and MHRA ATMP.
• OST-tADC (Tunable Drug Conjugates / Tunable Antibody Drug Conjugates) OS Therapies' second program, a Tunable Antibody Drug Conjugate platform that uses smaller targeting moieties, a pH-sensitive SiLinker, and Conditionally Active Payloads (CAPs) to deliver cancer-killing agents specifically inside tumor cells and acidic tumor microenvironments, with the goal of improving efficacy and reducing side effects across solid tumors.
• OS Animal Health OS Animal Health is OS Therapies' wholly owned subsidiary focused on canine osteosarcoma, commercializing OST-HER2 in the veterinary oncology market. It is planned to be spun off into a standalone public company in the first half of 2026, addressing a veterinary oncology market projected to reach $4.77 billion by 2034.

Quantifiable outcome

• 75% 2.5-year overall survival in OST-HER2 Phase 2b trial vs. 47% historical control (p=0.003)
• +4 more outcomes

Named customers2 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature6 records

Partnerships

Eight partnerships are on record, tiered core.

• Johnson & Johnson Innovation JLABScoreStrategic or Co-development PartnerOS Therapies' principal headquarters is located within JLABS NYC (101 6th Avenue, 3rd Floor, New York, NY 10013). JLABS provides incubator infrastructure, ecosystem access to Johnson & Johnson, and proximity to the New York biotech community. JLABS is referenced as a key operational and ecosystem partner.
• Ayala PharmaceuticalscoreStrategic or Co-development PartnerIn April 2025, OS Therapies acquired all listeria-based clinical, preclinical, and intellectual property assets from Ayala Pharmaceuticals in exchange for 4.8 million shares of OS Therapies common stock. Ayala subsequently completed its dissolution and liquidation on February 9, 2026, with no remaining securities in OS Therapies. The acquisition brought the listeria-based OST-HER2 platform fully in-house.
• Children's Oncology Group (COG) clinical trial sitescoreImplementation/ SI/ Consulting PartnerCOG is the clinical trial network used to administer the Phase 2b AOST-2121 study of OST-HER2 in recurrent, fully resected, pulmonary metastatic osteosarcoma across multiple U.S. pediatric oncology sites. The partnership is the foundation for the company's clinical distribution to patients.
• Dr. Robert "Bob" S. Langer (Strategic Advisory Board)coreStrategic or Co-development PartnerModerna co-founder and MIT Institute Professor Dr. Robert Langer was appointed to OS Therapies' strategic advisory board in April 2026 to assist with listeria oncology pipeline prioritization and tunable ADC candidate selection. Brings experience from over 40 co-founded ventures.
• Dr. Craig Eagle (Chief Medical Advisor)coreStrategic or Co-development PartnerFormer Guardant Health CMO, Genentech, and Pfizer veteran Dr. Craig Eagle appointed Chief Medical Advisor in May 2026 to oversee U.S., U.K., and European commercialization and reimbursement preparations, advance partnership discussions, and lead the upcoming FDA Pre-BLA meeting on seroconversion biomarker data.
• Dutch Medicines Evaluation Board (EMA Rapporteur)coreOthersThe Dutch Medicines Evaluation Board serves as the rapporteur for OS Therapies' OST-HER2 program; a positive rapporteur meeting was held on October 6, 2025, confirming safety, sufficient efficacy data, and pathways for conditional marketing authorization in Europe.
• U.S. Congress (Mikaela Naylon Give Kids A Chance Act)coreOthersU.S. Congress passed the Mikaela Naylon Give Kids A Chance Act, reauthorizing the Rare Pediatric Disease Designation Priority Review Voucher program through September 30, 2029. This extends OS Therapies' eligibility window for a PRV upon BLA approval for OST-HER2 from September 30, 2026 to September 30, 2029.
• OS Animal Health (planned spinoff)coreStrategic or Co-development PartnerOS Therapies announced the planned spinoff of its OS Animal Health subsidiary into a standalone public company in the first half of 2026. The spinoff will focus on OST-HER2 for canine osteosarcoma and tap into the broader veterinary oncology market projected to reach $4.77 billion by 2034.

Scale indicators10 records

Recent moves8 records

Expansion highlights7 records

Broad incumbents

• ImmunoGen (AbbVie): Established ADC platform company (acquired by AbbVie in 2024) with approved products including ELAHERE. Most directly comparable as a commercial-stage ADC platform validating the ADC market that OS Therapies' OST-tADC platform seeks to enter.
• Daiichi Sankyo: Global pharmaceutical company and leading ADC platform developer (Enhertu, Datroway) with major HER2 franchise. Comparable as the dominant incumbent in HER2-targeted oncology and the standard against which OST-tADC's pH-conditional payload release must differentiate.
• Adaptimmune Therapeutics: Clinical-to-commercial stage cell therapy company developing engineered T cell receptor therapies for solid tumors including HER2-expressing cancers. Comparable as a clinical-stage oncology platform company pursuing HER2+ solid tumors with a differentiated immune-based mechanism.

Emerging players

• Maverick Therapeutics: Clinical-stage biotech (acquired by Eli Lilly in 2022) developing T cell engagers targeting HER2 and other solid tumor antigens. Comparable as a HER2-targeted immuno-oncology platform with conditional/enhanced activation design principles similar in philosophy to OST-tADC's tumor microenvironment selectivity.
• Carisma Therapeutics: Clinical-stage macrophage-based immunotherapy company developing CAR-M cell therapies for solid tumors. Comparable as a small-cap clinical-stage oncology platform company pursuing novel immune-based mechanisms against hard-to-treat solid tumors.
• Pieris Pharmaceuticals: Clinical-stage biotech developing anticalin-based therapeutics including HER2-targeted candidates for solid tumors. Comparable as a small-cap clinical-stage platform company pursuing HER2+ solid tumors with a proprietary biologic delivery technology.

Direct peers

• Salarius Pharmaceuticals: Clinical-stage oncology company developing treatments for rare pediatric cancers including Ewing sarcoma and osteosarcoma. Comparable in mission (rare pediatric oncology), structure (small-cap clinical-stage), and target indication overlap.
• Oncternal Therapeutics: Clinical-stage oncology company focused on rare cancers, including Ewing sarcoma (a pediatric bone cancer adjacent to osteosarcoma). Comparable as a small-cap clinical-stage rare cancer biotech with regulatory designations and orphan drug pathway experience.
• Iterion Therapeutics: Clinical-stage oncology company developing tegavivint and other small molecules for osteosarcoma and other cancers. Most directly comparable peer given shared focus on osteosarcoma as a lead indication in a small-cap clinical-stage biotech structure.
• Ayala Pharmaceuticals: Former developer of the listeria-based OST-HER2 platform assets that OS Therapies acquired in April 2025. Ayala subsequently dissolved in February 2026, but was the direct prior developer of the lead asset and remains the most direct historical comparator for listeria-based oncology immunotherapy.

Market position

Strengths5 records

Weaknesses3 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

• Xx.com/OSTherapies
• Facebookfacebook.com/OSTherapies
• LinkedInlinkedin.com/company/os-therapies
• Instagraminstagram.com/ostherapies

Compliance7 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles8 records

Subsidiaries3 records

Funding overview

Funding rounds11 records

Investors5 records

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M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about OS Therapies