What IO Biotech does

IO Biotech was a clinical-stage biopharmaceutical company that developed immune-modulatory, off-the-shelf therapeutic cancer vaccines based on its proprietary T-win platform. Founded in 2014 in Copenhagen, Denmark, the company's T-win technology delivers peptide epitopes from immune-suppressive antigens (IDO1, PD-L1, arginase-1, and TGF-β) to activate and expand T cells that target both tumor cells and immune-suppressive cells in the tumor microenvironment, creating a pro-inflammatory milieu that potentiates anti-tumor activity. The lead candidate, Cylembio (IO102-IO103, imsapepimut and etimupepimut adjuvanted), combined vaccines targeting IDO1 and PD-L1 and was evaluated in combination with Merck's pembrolizumab (Keytruda) for first-line treatment of advanced melanoma, NSCLC, and head and neck cancers. The pipeline also included IO112 (arginase-1) and IO170 (TGF-β1) vaccine candidates.

The company operated under a clinical-stage business model with no product revenue, funded by capital markets and debt. IO Biotech completed a €127 million Series B in January 2021, an approximately $75 million private placement in August 2023, and up to €57.5 million in debt financing from the European Investment Bank announced in December 2024. The company completed its IPO on NASDAQ under ticker IOBT in November 2021, retaining global commercial rights to Cylembio and planning for a U.S. launch. The Phase 3 IOB-013/KN-D18 trial enrolled 407 patients across more than 100 sites in the US, Europe, Australia, Turkey, Israel, and South Africa, with pembrolizumab supplied by Merck under a clinical collaboration. Reported Phase 1/2 data included 80% objective response rate and 25.5-month median progression-free survival at five-year follow-up, published in Nature Medicine and Nature Communications.

In August 2025, the company announced Phase 3 results showing 19.4 months median PFS for Cylembio plus pembrolizumab versus 11.0 months for pembrolizumab alone, with a 23% reduction in risk of disease progression or death (HR 0.77) but a p-value of 0.056, narrowly missing statistical significance. In September 2025, the FDA recommended against BLA submission, prompting approximately 50% workforce reductions. The company engaged Raymond James in January 2026 to explore strategic alternatives and ultimately filed for Chapter 7 bankruptcy in March 2026, ceasing all operations with all directors stepping down and shareholders unlikely to receive liquidation proceeds.

Name

IO Biotech

Legal name

IO Biotech, Inc.

Website

https://iobiotech.com

Company type

Public

Founded year

2014

Operating status

Closed

Headcount range

51–100 employees

Short description

IO Biotech was a clinical-stage biopharmaceutical company developing immune-modulatory, off-the-shelf therapeutic cancer vaccines using its T-win platform, with lead candidate Cylembio for advanced melanoma. The company filed for Chapter 7 bankruptcy in March 2026 after the FDA rejected its BLA.

Ownership category

akta.pro rank

Product category

Oncology Biopharmaceuticals

NAICS

Biological Product (except Diagnostic) Manufacturing (325414), Research and Development in Biotechnology (except Nanobiotechnology) (541714)

SIC

Biological Products, (No Disgnostic Substances) (2836)

akta.pro primary industry

Therapeutic Vaccines (cancer, chronic infection immunotherapy) (HLAAAEAB)

akta.pro secondary industries

Therapeutic Vaccines (e.g., Cancer/Chronic Infection) (HLAIAEAG), Immuno-Oncology & Immune Monitoring Biomarkers (TMB, MSI, MRD, immune profiling) (HLAAAMAK), Immunology & Inflammation Pharmaceuticals (HLAIAAAD)

Keywords

• Therapeutic cancer vaccines
• Immune oncology
• Tumor microenvironment modulation
• Off-the-shelf peptide vaccines
• Clinical-stage biopharmaceutical

Headquarters

HQ city

Copenhagen

HQ country

Denmark

HQ region

Europe

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. Product Revenue (Future): Pre-commercial stage company. Planned U.S. product launch for Cylembio was expected in 2026 prior to FDA rejection. No revenue currently generated from product sales.
2. Debt Financing: European Investment Bank debt financing of up to €57.5 million to fund development of cancer vaccine candidates, with first disbursements expected in early 2025.
3. Private Placement Financing: $75 million private placement financing involving new and existing investors to support ongoing clinical trials, extending cash runway into late 2025.

Go-to-market motion2 records

Distribution channels2 records

Marketing channels5 records

Core offering

IO Biotech develops off-the-shelf, immune-modulatory therapeutic cancer vaccines built on its proprietary T-win® platform. Lead candidate Cylembio (IO102-IO103 / imsapepimut and etimupepimut, adjuvanted) combines peptide epitopes targeting IDO1 and PD-L1 and was evaluated in combination with pembrolizumab in a global Phase 3 trial for advanced melanoma, with additional Phase 2 studies in NSCLC and head and neck cancer. Pipeline candidates IO112 (arginase-1) and IO170 (TGF-βL1) extend the platform to other immune-suppressive pathways.

Product overview

IO Biotech is a clinical-stage biopharmaceutical company developing novel, immune-modulatory, off-the-shelf therapeutic cancer vaccines based on its proprietary T-win® platform. The company's lead product candidate is Cylembio (imsapepimut and etimupepimut, adjuvanted), also known as IO102-IO103, which combines two vaccines targeting IDO1 and PD-L1. The pipeline includes additional candidates IO112 (arginase-1 targeting) and IO170 (TGF-β targeting), all leveraging the T-win platform's dual mechanism of action to kill tumor cells and immune-suppressive cells in the tumor microenvironment.

Differentiator

Problem solved

Functional benefit

Brands

• T-win: The company's proprietary immune-modulatory vaccine technology platform designed to activate T cells to target both tumor cells and immune-suppressive cells in the tumor microenvironment.
• Cylembio

Products and services

• Cylembio (imsapepimut and etimupepimut, adjuvanted; also known as IO102-IO103) Cylembio (IO102-IO103) is IO Biotech's lead investigational immune-modulatory, off-the-shelf therapeutic cancer vaccine combining two vaccine components: IO102 targeting the IDO1 immune-suppressive antigen and IO103 targeting PD-L1. It is designed to kill both tumor cells and immune-suppressive cells in the tumor microenvironment by stimulating T cell activation against IDO1+ and/or PD-L1+ cells, with intended use in combination with pembrolizumab for advanced melanoma, NSCLC, and head and neck cancer.
• IO112 (Arginase-1 Vaccine) IO112 is a wholly owned IO Biotech T-win vaccine candidate designed to activate and expand T cells specific for arginase-1 positive/expressing cells in the tumor microenvironment. Arginase-1 is highly expressed in difficult-to-treat tumors including renal cell carcinoma, head and neck, breast, pancreatic, ovarian, colorectal and prostate cancers, positioning IO112 as a potential pipeline candidate for these indications.
• IO170 (TGF-βL1 Vaccine) IO170 is a novel T-win immune-modulatory therapeutic cancer vaccine candidate designed to target TGF-βL1-expressing cells in the tumor microenvironment. By stimulating T cell activity against TGF-βL1+ cells, the vaccine aims to modulate the TGF-β pathway and drive therapeutic benefit across tumors dependent on TGF-β signaling.

Quantifiable outcome

• 19.4 months median progression-free survival (mPFS) vs 11.0 months for pembrolizumab alone in Phase 3 trial
• +4 more outcomes

Named customers1 record

Segments3 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

Two partnerships are on record, tiered core.

• Merck (MSD)coreStrategic or Co-development Partner · 3 November 2022Clinical collaboration with Merck (known as MSD outside US and Canada) to evaluate IO102-IO103 in combination with KEYTRUDA (pembrolizumab). Merck supplies pembrolizumab for clinical trials while IO Biotech sponsors the trials and maintains global commercial rights. Partnership includes Phase 3 trial (IOB-013/KN-D18) in advanced melanoma and Phase 2 basket trials in lung and head/neck cancers.
• Herlev University Hospital / Center for Cancer Immune TherapycoreStrategic or Co-development PartnerInvestigator-initiated trial (MM1636) conducted at Copenhagen University Hospital, Herlev. Scientific co-founders Dr. Mads Hald Andersen and Dr. Inge Marie Svane serve at this institution. Publication of five-year outcomes in Nature Communications.

Scale indicators10 records

Recent moves10 records

Expansion highlights6 records

Direct peers

• Moderna: Moderna is developing mRNA-based therapeutic cancer vaccines, including personalized neoantigen programs (mRNA-4157) in melanoma in combination with Merck's pembrolizumab. Directly comparable as a clinical-stage therapeutic cancer vaccine developer targeting the same checkpoint-inhibitor combination space as IO Biotech's Cylembio.
• BioNTech: BioNTech is a leading mRNA cancer vaccine developer with FixVac (off-the-shelf shared-antigen) and individualized neoantigen programs across melanoma and other solid tumors. Closely comparable to IO Biotech's off-the-shelf, immune-modulatory vaccine approach with multiple clinical-stage candidates.
• Gritstone bio: Gritstone bio developed neoantigen cancer vaccines (GRANITE, SLATE) and similarly pursued first-line metastatic melanoma combinations with checkpoint inhibitors. It filed for bankruptcy in 2024 after a Phase 2 failure, making it a highly comparable cautionary precedent for IO Biotech's trajectory.
• Bavarian Nordic: Bavarian Nordic develops therapeutic cancer vaccines including its CV301 platform targeting CEA and MUC1 antigens in combination with checkpoint inhibitors. Comparable as a clinical-to-commercial stage developer of off-the-shelf therapeutic cancer vaccines in oncology.
• Transgene: Transgene is a French clinical-stage biotech developing therapeutic cancer vaccines using viral-vector technology (TG4050 individualized neoantigen vaccine and TG4001 HPV-targeted). Comparable as a clinical-stage developer of therapeutic cancer vaccines often combined with checkpoint inhibitors.
• Northwest Biotherapeutics: Northwest Biotherapeutics develops DCVax, a dendritic cell-based therapeutic cancer vaccine platform for glioblastoma and other solid tumors. Comparable as a clinical-stage developer of immune-cell-based therapeutic cancer vaccines targeting solid tumors.
• VBI Vaccines: VBI Vaccines is a clinical-stage biotech developing immunotherapeutic vaccines including eVLP-based candidates for oncology indications. Comparable as a clinical-stage therapeutic vaccine developer operating in the immune-oncology space.

Emerging players

• Nouscom: Nouscom is a privately held biotech developing off-the-shelf, vector-based neoantigen cancer vaccines in solid tumors. Comparable emerging-stage therapeutic cancer vaccine developer using a similar off-the-shelf, combination-therapy approach as IO Biotech's Cylembio.

Broad incumbents

• Merck & Co. (MSD): Merck is the maker of Keytruda (pembrolizumab), the checkpoint inhibitor used as both the combination partner and comparator in IO Biotech's Phase 3 trial. It is also a broader incumbent in immuno-oncology with a deep oncology pipeline and was IO Biotech's clinical-trial partner under a 2022 collaboration.
• Bristol-Myers Squibb: Bristol-Myers Squibb is a broad incumbent in immuno-oncology with Opdivo (nivolumab) and Yervoy (ipilimumab) as foundational checkpoint inhibitors. Comparable as a leading competitor defining the treatment landscape IO Biotech's Cylembio sought to enter in first-line melanoma.

Market position

Strengths4 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xtwitter.com/IOBiotech
• LinkedInlinkedin.com/company/io-biotech

Revenue estimate

Valuation estimate

Number of profiles

Profiles22 records

Subsidiaries1 record

Funding overview

Funding rounds7 records

Investors17 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

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

Frequently asked questions about IO Biotech