RayzeBio Launches with $45 Million Series A to Advance Portfolio of Targeted Radiopharmaceuticals for Cancer Therapeutics

— Robust pipeline of drugs against validated oncology targets —
— Focus on delivering Actinium-225, a powerful alpha-emitting radioisotope —
— Led by repeatedly successful management team —

SAN DIEGO, California, October 14, 2020

RayzeBio, Inc. announced today a $45M Series A financing to advance the development of its broad pipeline of targeted radiopharmaceuticals. Co-lead investors venBio Partners and Versant Ventures were joined by Samsara BioCapital.

“The field of radiopharmaceuticals represents one of the most attractive untapped opportunities in oncology,” said Ken Song, M.D., President and CEO of RayzeBio. “We have a clear and systematic strategy to tackle this space, including key partnerships and a suite of rationally designed radiopharmaceutical medicines that can meaningfully impact outcomes for cancer patients.”

Emerging field of radiopharmaceuticals

Radiation treatment of cancer has been in practice for decades with external delivery of radiation beams as the primary mode of therapy. In contrast, radiopharmaceuticals, which involve the use of therapeutic radioisotopes administered systemically and targeted to tumors, are emerging as an important area in precision oncology. 

“The radiopharmaceutical field is reaching a new inflection due to multiple scientific and translational advances as well as recent clinical demonstration of dramatic efficacy. We believe RayzeBio has the potential to generate similar results across multiple precision oncology targets, a feat that no other company has accomplished,” said Jerel Davis, Ph.D., Managing Director at Versant and a RayzeBio board member. 

Radiopharmaceuticals enable a theranostic approach wherein the same drug conjugate is used for both diagnostic imaging and therapy by switching out the radioisotope. Doctors can directly visualize tumor uptake of the drug in patients prior to determining which patients should proceed with treatment. This provides a significant advantage for radiopharmaceuticals compared with other cancer treatment modalities.

RayzeBio’s differentiated approach

RayzeBio built its pipeline by coordinating across three main areas – target selection, binder selection and isotope selection. 

  • Target selection – Solid tumor targets that have been clinically validated but not yet explored with radiopharmaceuticals were prioritized. This yielded at least 10 promising targets to pursue. 
  • Binder selection – In selecting the molecule type that binds to targets of interest, multiple factors ranging from affinity to tumor penetration and pharmacokinetics were considered. Macrocyclic peptide mimetics were identified as a promising approach and RayzeBio established a partnership with PeptiDream (Tokyo, Japan) for de novo discovery of binders.
  • Isotope selection – Actinium-225, an alpha-emitting isotope, is the primary nuclear payload for RayzeBio given its potent cell killing and focused energy release to a few cell diameters thereby minimizing damage to surrounding normal tissues. RayzeBio has secured relationships with suppliers of Actinium-225.

“RayzeBio represents the most attractive opportunity in the radiopharmaceutical space given the breadth of its pipeline, its well thought-out plans to design best-in-class drugs, and the fact it is led by a highly driven, experienced and entrepreneurial team,” said Aaron Royston, M.D., Managing Partner at venBio.

Expanded team of RayzeBio

In addition to Dr. Song, the management team launching RayzeBio includes Deborah Charych, Ph.D., co-founder and CTO, and a pharma and biotech industry veteran to lead the biology group. The team has extensive industry experience, having contributed to the development and launch of multiple healthcare products as well as billions of dollars of value creation. 

The board of directors includes Dr. Davis; Aaron Kantoff, a founding independent board member of RayzeBio and venture partner at Medicxi; Dr. Royston; and Dr. Song. Samsara’s Mike Dybbs, Ph.D., serves as a board observer.

The company has built relationships with the following clinical and scientific initial advisors and is continuing to expand its network as it makes progress on the various programs.

  • Carolyn Bertozzi, Ph.D. – Professor of Chemical & Systems Biology and Radiology at Stanford University and Investigator of the Howard Hughes Medical Institute
  • Thomas Hope, M.D. – Associate Professor and Director of Molecular Therapy for the Molecular Imaging and Therapeutics Clinical Section at University of California San Francisco 
  • George Sgouros, Ph.D. – Professor and Director of Radiological Physics Division at Johns Hopkins University
  • Wolfgang Weber, M.D. – Professor and Director of the Department of Nuclear Medicine at the Technical University of Munich in Germany (TUM)

About RayzeBio

RayzeBio is a biotechnology company that aims to improve clinical benefit by efficiently developing innovative tumor-targeted small molecule medicines that harness the power of radioisotopes. With a focus on clinically validated solid tumor targets, RayzeBio is developing novel macrocyclic peptide mimetic binders to deliver potent therapeutic radioisotopes such as Actinium-225, an alpha-emitter. The company is backed by a syndicate of sophisticated healthcare investors and was established in 2020 by co-founders Deborah Charych, Aaron Kantoff, and Aron Knickerbocker. For additional information, please visit www.rayzebio.com

Ken Song, M.D.
(858) 257-3449