# Ona Therapeutics
Ona Therapeutics SL is a Barcelona-based biopharmaceutical startup, founded in 2019 as a spin-off of the Institute for Research in Biomedicine (IRB Barcelona) and ICREA, that develops antibody-drug conjugates (ADCs) for treatment-resistant cancers.[1](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html) The company works from the Barcelona Science Park (PCB-UB), and on 4 June 2026 it closed an oversubscribed $86.6 million Series B to move its first ADC into human trials.[1](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html) • [2](https://www.pcb.ub.edu/en/ona-therapeutics-raises-86-6-million-series-b-to-advance-first-in-class-adcs-into-clinical-development/)
| Fact | Detail |
|---|---|
| Founded | 2019, Barcelona, as a spin-off of IRB Barcelona and ICREA[3](https://medcitynews.com/2026/06/startup-secures-86m-to-take-on-one-of-the-challenges-for-adcs-in-breast-cancer/) |
| Scientific origin | Laboratory of Salvador Aznar Benitah (metastasis and lipid-metabolism biology)[4](https://european-biotechnology.com/latest-news/ona-therapeutics-bags-86-6m-series-b-for-stealth-adc-push/) |
| Base | Barcelona Science Park (PCB-UB)[2](https://www.pcb.ub.edu/en/ona-therapeutics-raises-86-6-million-series-b-to-advance-first-in-class-adcs-into-clinical-development/) |
| Sector | Oncology biologics, chiefly antibody-drug conjugates[1](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html) |
| Funding | €30 million Series A (2020); $86.6 million Series B (June 2026)[3](https://medcitynews.com/2026/06/startup-secures-86m-to-take-on-one-of-the-challenges-for-adcs-in-breast-cancer/) • [1](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html) |
| Series B co-leads | Columbus Venture Partners and Mérieux Equity Partners[1](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html) |
| Status | Active, independent; entering clinical development as of mid-2026[5](https://endpoints.news/adc-biotech-ona-therapeutics-secures-86-6m-in-series-b-raise/) |
## Founding and scientific origins
Ona was founded in Barcelona in 2019 as a spin-off of IRB Barcelona and ICREA, building on research from the laboratory of [Salvador Aznar Benitah](https://www.edgepedia.org/salvador-aznar-benitah).[4](https://european-biotechnology.com/latest-news/ona-therapeutics-bags-86-6m-series-b-for-stealth-adc-push/) The founding thesis concerned lipid metabolism in spreading cancer: the lab identified CD36, a fatty-acid transporter, as a key regulator of metastasis in several tumor types, and preclinical studies suggested that blocking the receptor could impair metastatic dissemination.[4](https://european-biotechnology.com/latest-news/ona-therapeutics-bags-86-6m-series-b-for-stealth-adc-push/) • [6](https://ona-therapeutics.com/)
Ona's most advanced publicly known program before its ADC focus was ONA-01, a monoclonal antibody against CD36; the company still lists a CD36 antibody on its pipeline, describing CD36 as a metabolic regulator of fatty-acid transport implicated in cancer progression.[4](https://european-biotechnology.com/latest-news/ona-therapeutics-bags-86-6m-series-b-for-stealth-adc-push/) • [6](https://ona-therapeutics.com/) By 2025 and 2026, the company's public identity had shifted to ADCs: engineered antibodies carrying cytotoxic payloads, directed at antigens that emerge when tumors stop responding to existing therapies.[1](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html)
## Pipeline, technology and clinical progress
ONA-255 is the lead candidate, an ADC in development for HR-positive, HER2-negative breast cancer, which CEO Valerie Vanhooren described to Drug Target Review as the most common type of breast cancer.[3](https://medcitynews.com/2026/06/startup-secures-86m-to-take-on-one-of-the-challenges-for-adcs-in-breast-cancer/) It carries a microtubule-inhibitor payload, which MedCity News notes differs from many currently available ADCs, and targets an antigen that Vanhooren said is upregulated in tumors resistant to therapies including Enhertu, the AstraZeneca–[Daiichi Sankyo](https://www.edgepedia.org/daiichi-sankyo) topoisomerase ADC.[3](https://medcitynews.com/2026/06/startup-secures-86m-to-take-on-one-of-the-challenges-for-adcs-in-breast-cancer/)
In her June 2026 interview with Endpoints News, Vanhooren said Ona is almost ready to start a Phase 1a dose-escalation trial of ONA-255 in breast cancer patients previously treated with CDK inhibitors and Enhertu, to be followed by Phase 1b dose optimization and a Phase 2 study, with 130 patients to be enrolled across all three stages.[5](https://endpoints.news/adc-biotech-ona-therapeutics-secures-86-6m-in-series-b-raise/) The second candidate, ONA-389, should be ready to enter a first-in-human trial in microsatellite-stable colorectal cancer in about a year and a half from June 2026.[5](https://endpoints.news/adc-biotech-ona-therapeutics-secures-86-6m-in-series-b-raise/) In a 15 June 2026 company-published interview, Vanhooren additionally said ONA-389 targets colorectal and hepatocellular carcinoma, a broader statement than the press release's colorectal indication.[7](https://ona-therapeutics.com/press-release/antibody-conjugates-for-drug-resistant-cancers/) The pipeline also includes ONA-418, a dual-payload ADC for prevalent solid tumors, which the CEO described as in a holding position.[3](https://medcitynews.com/2026/06/startup-secures-86m-to-take-on-one-of-the-challenges-for-adcs-in-breast-cancer/) • [7](https://ona-therapeutics.com/press-release/antibody-conjugates-for-drug-resistant-cancers/)
The targets of ONA-255 and ONA-389 are undisclosed. According to BioCentury, Ona says its lead program is engineered to have a higher therapeutic index than other ADCs, meaning a wider margin between effective dosing and toxic dosing.[8](https://www.biocentury.com/article/659660/ona-s-86-6m-venture-round-among-spain-s-biggest-for-a-biotech-finance-report) Per Endpoints News, ONA-255 and ONA-389 share the same undisclosed target, which the company says appears upregulated as patients receive CDK inhibitors or develop resistance to topoisomerase ADCs like Enhertu; the two candidates use different linker payloads.[5](https://endpoints.news/adc-biotech-ona-therapeutics-secures-86-6m-in-series-b-raise/)
## Funding by the numbers
Ona raised €30 million in Series A financing in 2020, the year after spinning out of IRB Barcelona and ICREA.[3](https://medcitynews.com/2026/06/startup-secures-86m-to-take-on-one-of-the-challenges-for-adcs-in-breast-cancer/) On 4 June 2026 it announced the closing of an oversubscribed $86.6 million Series B, co-led by new investors Columbus Venture Partners and Mérieux Equity Partners, with COFIDES and Korys joining all existing investors: Alta Life Sciences, Asabys Partners, Bpifrance (InnoBio strategy), CDTI through SICC Innvierte, FundPlus NV, and [Ysios Capital](https://www.edgepedia.org/ysios-capital).[1](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html) Some outlets rounded the round to $87 million.[9](https://www.thepharmaletter.com/pharma-news/ona-raises-87-million-to-move-first-adc-into-human-studies)
The proceeds fund clinical development of ONA-255 toward clinical proof of concept and advancement of ONA-389 toward first-in-human studies.[1](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html) Vanhooren told Endpoints News the cash should provide two-and-a-half to three years of runway, and the company says it retains full worldwide commercial rights to all its assets.[5](https://endpoints.news/adc-biotech-ona-therapeutics-secures-86-6m-in-series-b-raise/) • [1](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html) BioCentury characterized the round as among Spain's biggest venture rounds for a biotech.[8](https://www.biocentury.com/article/659660/ona-s-86-6m-venture-round-among-spain-s-biggest-for-a-biotech-finance-report)
## Recent developments
The record shows a shift from preclinical target discovery into clinical execution. The CD36 program (ONA-01) was the most advanced publicly known effort before the company's ADC focus.[4](https://european-biotechnology.com/latest-news/ona-therapeutics-bags-86-6m-series-b-for-stealth-adc-push/) In late 2025, Vanhooren disclosed ONA-255's payload and indication to Drug Target Review.[3](https://medcitynews.com/2026/06/startup-secures-86m-to-take-on-one-of-the-challenges-for-adcs-in-breast-cancer/) The June 2026 Series B then marked the transition into clinical development, with ONA-255 near first-in-human dosing and ONA-389 advancing behind it.[5](https://endpoints.news/adc-biotech-ona-therapeutics-secures-86-6m-in-series-b-raise/) • [4](https://european-biotechnology.com/latest-news/ona-therapeutics-bags-86-6m-series-b-for-stealth-adc-push/)
## References
1. [Ona Therapeutics Raises $86.6 Million Series B to Advance First-in-Class ADCs into Clinical Development (GlobeNewswire)](https://www.globenewswire.com/news-release/2026/06/04/3306533/0/en/Ona-Therapeutics-Raises-86-6-Million-Series-B-to-Advance-First-in-Class-ADCs-into-Clinical-Development.html)
2. [Ona Therapeutics Raises $86.6 Million Series B (Parc Científic de Barcelona)](https://www.pcb.ub.edu/en/ona-therapeutics-raises-86-6-million-series-b-to-advance-first-in-class-adcs-into-clinical-development/)
3. [Startup Secures $86M to Take On One of the Challenges for ADCs in Breast Cancer (MedCity News)](https://medcitynews.com/2026/06/startup-secures-86m-to-take-on-one-of-the-challenges-for-adcs-in-breast-cancer/)
4. [Ona Therapeutics bags $86.6m Series B for stealth ADC push (European Biotechnology Magazine)](https://european-biotechnology.com/latest-news/ona-therapeutics-bags-86-6m-series-b-for-stealth-adc-push/)
5. [ADC biotech Ona Therapeutics secures $86.6M in Series B raise (Endpoints News)](https://endpoints.news/adc-biotech-ona-therapeutics-secures-86-6m-in-series-b-raise/)
6. [Ona Therapeutics — Home Page (company website)](https://ona-therapeutics.com/)
7. [Antibody conjugates for drug resistant cancers (Ona Therapeutics press page)](https://ona-therapeutics.com/press-release/antibody-conjugates-for-drug-resistant-cancers/)
8. [Ona's $86.6M venture round among Spain's biggest for a biotech: Finance Report (BioCentury)](https://www.biocentury.com/article/659660/ona-s-86-6m-venture-round-among-spain-s-biggest-for-a-biotech-finance-report)
9. [Ona raises $87 million to move first ADC into human studies (The Pharmaletter)](https://www.thepharmaletter.com/pharma-news/ona-raises-87-million-to-move-first-adc-into-human-studies)
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*Initially written Sep 17, 2026 · Edited: Oct 11, 2026; Oct 15, 2026*
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