OXFORD, ENGLAND – September 16, 2025 – Yellowstone Biosciences Limited (“Yellowstone” or the “Company”), a pioneer of soluble bispecific T-cell receptor (TCR)-based therapies for human leukocyte antigen Class II (“HLA Class II”) targets in oncology, today announced the appointment of Jim MacDonald as its Chief Executive Officer and member of its Board of Directors.
Mr. MacDonald brings more than 25 years of leadership and experience to Yellowstone. He most recently served as Venture Partner at Altitude Life Science Ventures. Previously, he was Co-Founder and Executive Vice President & General Counsel at Sana Biotechnology, where he played a key role in securing the foundational intellectual property for the company, building and scaling the business, and undertaking its private financings and Nasdaq IPO. Earlier, he served as Senior Vice President and Chief Intellectual Property Officer at Juno Therapeutics, contributing to the scaling of the company, its private financings and Nasdaq IPO, and the acquisition by Celgene.
“Jim is a proven biotech leader with extensive experience in building innovative life sciences companies,” said Neil Johnston, Chair of Yellowstone. “His experience with advancing novel oncology platforms and executing strategic financings will be instrumental as Yellowstone advances its HLA Class II programmes toward the clinic.”
“Jim’s leadership comes at a critical moment for Yellowstone,” said Prof. Paresh Vyas, Co-Founder and Chief Scientific Officer of Yellowstone. “His experience in scaling high-growth biotech companies will be invaluable as we translate our HLA Class II science into a robust pipeline and advance toward the clinic.”
“I am excited to join Yellowstone at this pivotal stage,” said Jim MacDonald, Chief Executive Officer of Yellowstone. "Yellowstone’s pioneering science in HLA Class II therapeutics has the potential to transform outcomes for patients with AML and solid tumours, and I look forward to working with the team to realise that promise."
About Yellowstone Biosciences
Yellowstone Biosciences, spun out of the University of Oxford with support from Oxford University Innovation (OUI) and Syncona Limited, is advancing soluble bispecific T-cell receptor (TCR)-based therapies targeting human leukocyte antigen Class II (“HLA Class II”) antigens. Yellowstone is founded on the pioneering research of Professor Paresh Vyas, a world-renowned scientific academic, key opinion leader and practising clinician with a specialist focus on acute myeloid leukaemia (“AML”). The Company is leveraging a proprietary biobank developed in Professor Vyas’ laboratory and novel antigen discoveries to develop a new class of highly selective cancer therapeutics, initially focused on AML and solid tumours. For more information, please visit www.yellowstonebio.com.
Yellowstone Biosciences Contacts:
Paresh Vyas, Co-Founder and Chief Scientific Officer
Julian Hirst, Co-Founder and Chief Financial Officer
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