Spain-based Ona Therapeutics has closed an oversubscribed USD 86.6 million Series B financing round to advance its antibody-drug conjugate (ADC) pipeline targeting treatment-resistant cancers. The Barcelona-based company, a spinout from IRB Barcelona and ICREA, is developing first-in-class ADCs directed at novel tumor-specific antigens associated with resistance biology — an area where established ADC programs have shown limited efficacy.
The round was co-led by new investors Columbus Venture Partners and Mérieux Equity Partners, with additional participation from COFIDES and Korys. All existing investors — Alta Life Sciences, Asabys Partners, Bpifrance via its InnoBio strategy, CDTI through SICC Innvierte, FundPlus NV, and Ysios Capital — also participated. Proceeds will fund clinical advancement of lead program ONA-255 in breast cancer toward proof of concept, and progress ONA-389 in colorectal cancer toward first-in-human studies. No prior funding rounds were detailed in the available disclosure.
Ona's pipeline centers on two lead ADC programs. ONA-255 targets breast cancer and is the more advanced asset, with the company now transitioning into clinical-stage operations. ONA-389 addresses colorectal cancer and is advancing toward first-in-human testing. The company has also indicated early-stage interest in gastric and liver cancers. Ona has not made public the specific molecular targets of any of its pipeline candidates.
The company's discovery approach relies on a patient-driven target identification platform designed to surface tumor-specific antigens and epitopes linked to resistance mechanisms in advanced disease. This is combined with antibody engineering, payload selection, and linker-payload optimization to generate ADCs intended to improve the therapeutic index relative to earlier-generation approaches — a challenge that has constrained the clinical utility of several approved ADCs.