Radiopharmaceuticals Startup RayzeBio Seeks Public Debut After Raising $400M From Investors

RayzeBio Inc, a San Diego company focused on radiopharmaceutical therapies for cancer, filed on Thursday to raise up to $100 million in an initial public offering.

The phase 3-stage company was founded in 2020 and plans to list on the Nasdaq under the symbol RYZB. 

The company's lead candidate, RYZ101, is designed to deliver a highly potent alpha particle radioisotope, Actinium 225 (Ac225), to tumors overexpressing somatostatin receptor (SSTR). 

RayzeBio says that a radiopharmaceutical therapeutic (RPT) utilizing Ac225 has the potential to provide greater efficacy over approved beta particle radioisotope Lutetium 177, or Lu177, therapies. 

Alpha particles can deliver up to 400 times higher energy than beta particles, leading to double-stranded DNA breaks, lethal to cancer cells.

The company started a phase 3 trial of the lead candidate RYZ101 for gastroenteropancreatic neuroendocrine tumors in May.

The candidate is also being tested in a phase 1 study of SSTR-expressing extensive-stage small-cell lung cancer patients. 

In its filing, RayzeBio described its hopes for RYZ101 to become a "pipeline-in-a-product" that could be used for other SSTR2-expressing cancers.

The IPO proceeds will also be funneled toward developing RYZ801 and RYZ811, two GPC3-targeting radiopharmaceuticals gearing up for phase 1 trials in hepatocellular carcinoma. 

The company plans to file for an IND for each candidate in 1H of 2024.

The company has secured $418 million in funding from a group of premier life science investors, including venBio Partners, Venrock Healthcare Capital Partners, Versant Ventures, and Viking Global Investors.