Theonie Anastassiadis

Theonie Anastassiadis, Ph.D., is an Origination Partner at Flagship Pioneering, where she conceives, builds, and grows Flagship’s next generation of breakthrough biotechnology companies. She currently serves as Founding President of Prologue Medicines, a company harnessing the power of viral evolution to create transformative therapies. Previously, she was a co-founder of Alltrna, a tRNA platform company, where she served as Chief Innovation Officer from 2018 to 2024.

Prior to joining Flagship in 2018, Theonie conducted doctoral research in Cell and Molecular Biology with a focus on Cancer Biology at the Perelman School of Medicine at the University of Pennsylvania. Her work on replication fork dynamics in cancer development and therapeutics was supported by multiple fellowships, including a four-year NIH F31 NRSA Predoctoral Fellowship.

Theonie is an inventor on 15+ published patent applications and has authored numerous scientific publications in journals including Nature Biotechnology, Molecular Cell, and the Journal of Biological Chemistry. She has been recognized in Endpoints News' 20 under 40 list of the next generation of biotech leaders and in Boston Business Journal's 40 under 40 list for successful professionals giving back to their community. She is a Business Advisory Board member of the Harvard Institute for RNA Medicine and a 2026–2027 fellow in the JOURNEY to Lead program.

Theonie received her Ph.D. in Cell and Molecular Biology from the University of Pennsylvania and holds a B.S. in Biology with honors from Haverford College. She also completed the Wharton Business Foundations Specialization.