Ona Therapeutics Appoints Oncology Drug Development Veteran Dr. Antoine Yver as Chair to Accelerate ADC Programs to Clinical Inflection Points

• Brings over 35 years of oncology drug development experience, including senior executive leadership roles at AstraZeneca and Daiichi Sankyo
• Led the development and approval of multiple breakthrough medicines such as ENHERTU^®, TAGRISSO^®, and LYNPARZA^®
• Strengthens Ona's transition to a clinical-stage company with ONA-255, while advancing its pipeline of first-in-class ADCs targeting major solid tumors
  

BARCELONA, Spain, Oct. 14, 2025 /PRNewswire/ -- Ona Therapeutics ("Ona"), a global biotech company pioneering first-in-class antibody-drug conjugates (ADCs), today announced the appointment of Dr. Antoine Yver, M.D., M.Sc., as Chair of its Board of Directors. This strategic appointment marks a defining step in the Company's growth as it prepares to advance its lead ADC, ONA-255, into clinical trials for breast cancer treatment in early 2026.

With over 35 years of leadership in global oncology drug development, Dr. Antoine Yver has held senior executive roles at industry leaders including Daiichi Sankyo, AstraZeneca, Johnson & Johnson, and Merck. He has played a key role in advancing and securing regulatory approvals for 13 landmark cancer therapies, including breakthrough medicines such as ENHERTU, TAGRISSO, and LYNPARZA, all of which have transformed standards of care for patients worldwide.

At Daiichi Sankyo, Dr. Yver served as Global Head of Oncology R&D, and at AstraZeneca, he led the oncology development programs. His leadership in bringing ENHERTU, a pioneering ADC for breast cancer, from initial first-in-human clinical studies to global approval, exemplifies his deep expertise and will be invaluable to Ona as it advances its innovative ADC pipeline toward clinical development.

Valerie Vanhooren, Ph.D., Co-Founder and Chief Executive Officer at Ona Therapeutics, said:"Antoine's unparalleled experience in advancing first-in-class oncology drugs at lightning speed from translational research through global approval will be critical as we advance our lead candidate, ONA-255, into clinical development in breast cancer. Equally important is our commitment to progressing our second ADC, ONA-389, targeting microsatellite stable (MSS) colorectal cancer and hepatocellular carcinoma, both high-unmet-need indications with significant market potential. Antoine's patient-centric vision aligns perfectly with Ona's mission to deliver transformative ADC therapies, and his strategic guidance will be invaluable as we accelerate growth and value creation in this next phase."

Dr. Yver is currently an Independent Director on the Board of Sanofi, where he contributes strategic and scientific insight at the governance level. He also serves on the boards of several oncology-focused companies, as well as the scientific advisory committee for Gustave Roussy Cancer Institute, further demonstrating his broad scientific and business influence and commitment to advancing cancer therapies.

Ona's proprietary patient-based discovery platform uniquely unlocks new biological targets that are not exploited by current ADCs or standard therapies, giving the Company a significant competitive edge. Its lead candidate, ONA-255, targets a unique first-in-class mechanism and is perfectly suited for the treatment of advanced cancers, particularly breast cancer. This candidate is advancing toward clinical trials in early 2026 and is also demonstrating broad potential across breast, gastric, and other solid tumors. Its second candidate, ONA-389, is focused on high-unmet-need indications such as MSS colorectal cancer and hepatocellular carcinoma. Together, these programs underscore Ona's innovative approach to developing transformative therapies for difficult-to-treat solid tumors.

Dr. Antoine Yver, M.D., M.Sc., newly appointed Chair of the Board of Ona Therapeutics, added: "Breast cancer remains the most prevalent cancer among women worldwide. Having witnessed firsthand the transformative impact ADCs can have for the treatment paradigm of breast cancer and the direct clinical benefit for patients, I recognize the compelling potential of Ona's approach in identifying novel tumor targets in breast cancer and other major solid tumors. I'm thrilled to join the Company at this pivotal stage to help ensure clinical readiness, guide swift, focused, and effective development strategy, and support the team in executing and advancing its pipeline and bringing next-generation ADCs to the patients who need them most."

About Ona Therapeutics
Ona Therapeutics is pioneering the development of first-in-class antibody-drug conjugates (ADCs) that exploit the molecular underpinnings of advanced cancer. Ona collaborates with renowned academics, clinicians, and clinical research partners. This collaborative approach enables the identification of novel therapeutic targets derived from the unique biology of treatment-refractory advanced cancer patients. Ona's approach combines biological insight with expertise in biologics to design ADCs and antibody therapies using target validation, optimized payload design, and validated linker-payload technology to provide effective treatments for patients with limited options. Its precision-engineered ADC pipeline consists of first-in-class ADCs, targeting aggressive and refractory cancer indications. The lead ADC, ONA-255, targeting breast cancer and solid tumors is in active IND development and will enter clinical development in early 2026. The company is also expanding its target indications into additional aggressive cancer types, including gastric, liver, and colon cancers. For further information visit our new website here https://ona-therapeutics.com/