RayzeBio Announces First Patient Dosed in Phase 3 ACTION-1 Study, Evaluating RYZ101 (Actinium-225 DOTATATE) in Neuroendocrine Tumors

-- RYZ101 on track to be the first approved Actinium-225 radiopharmaceutical therapy for the industry

SAN DIEGO--(BUSINESS WIRE)--RayzeBio, Inc., a targeted radiopharmaceutical company developing an innovative pipeline against validated solid tumor targets, today announced that the first patient has been dosed in the Phase 3 trial of RYZ101 in patients with SSTR+ gastroenteropancreatic neuroendocrine tumors (GEP-NETs) that have progressed following prior Lutetium-177 labelled somatostatin analogue therapy.

“Patients with GEP-NETs have very limited options upon progression after Lutetium-177 labelled somatostatin analogue therapy,” said Dr. Thomas Hope, M.D., Vice Chair of Clinical Operations and Strategy in the Department of Radiology. “With existing results using Actinium-225 DOTATATE suggesting clinical benefit, we are excited to be moving this therapy forward in the ACTION-1 study.”

The Phase 3 trial is a global study and expected to enroll 210 patients, randomized 1:1 between RYZ101 and investigator’s choice of standard of care (SOC), which includes everolimus, sunitinib, or high-dose long-acting SSAs. The primary endpoint for the trial is progression free survival (PFS). Patients randomized to SOC are allowed to crossover to RYZ101 upon disease progression.

“We are very encouraged by the continued interest in and potential of RYZ101. I look forward to working with the GEP-NET community to advance RYZ101 in this important therapeutic indication. RYZ101 was well tolerated in the Phase 1b trial and we look forward to providing updates on efficacy from the Phase 1b trial even as we continue to enroll patients in the Phase 3 trial,” said Susan Moran, M.D., M.S.C.E., Chief Medical Officer of RayzeBio.

About gastroenteropancreatic neuroendocrine tumors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare tumors with an incidence of approximately 18,000 patients annually in the United States. Many GEP-NETs follow an indolent disease course and thus the prevalence of patients with GEP-NETs in the United States is several fold that of the incidence. The prognosis for patients with GEP-NET tumors depends on tumor grade and other histopathologic characteristics. Approximately 80% of GEP-NETs express the somatostatin receptor type 2 (SSTR2). Lutathera is a targeted radiopharmaceutical therapy comprised of a somatostatin analog peptide labeled with the beta-emitting radioisotope Lutetium-177 (Lu177), which received regulatory approval for treatment of adult patients with SSTR+ GEP-NETs in Europe and the United States in 2017 and 2018, respectively. However, most patients who receive Lu177-based somatostatin therapies eventually experience tumor progression and have limited subsequent treatment options.

About RYZ101

RYZ101 is an investigational targeted radiopharmaceutical therapy, designed to deliver a highly potent radioisotope, Actinium-225 (Ac225), to tumors expressing SSTR2. RYZ101 is being evaluated in clinical studies for patients with SSTR+ GEP-NETs who have previously been treated with Lu177-based somatostatin therapies and also in patients with newly diagnosed extensive stage small cell lung cancer. Details of the studies can be found at https://clinicaltrials.gov/ct2/show/NCT05477576 and https://clinicaltrials.gov/ct2/show/NCT05595460.

Ac225 for the study was provided by multiple sources including the U.S. Department of Energy Isotope Program.

About RayzeBio

RayzeBio is a biotechnology company focused on improving outcomes for people with cancer by harnessing the power of targeted radioisotopes. With a focus on clinically validated solid tumor targets, RayzeBio is developing novel drug conjugates 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. For additional information, please visit www.rayzebio.com