Four additional sites open for recruitment in Oncoinvent’s Phase 2 trial

Oslo, Norway, 29 January 2026: Oncoinvent, a clinical stage, radiopharmaceutical company developing innovative treatments for solid cancers, today announces that the first patient has been enrolled at one of the newly activated sites in its Phase 2 study of Radspherin® in patients with peritoneal carcinomatosis from ovarian cancer.

The randomized part of the study has been actively recruiting patients at six sites since March 2025. Four additional sites have now been opened, and the first patient has been enrolled at one of these newly activated sites.

“The process of opening new clinical sites involves extensive regulatory reviews, contracting, and site-readiness work. We are therefore pleased to see both the successful activation of additional sites and the enrollment of the first patient at a newly onboarded site,” said Kari Myren, Chief Medical Officer at Oncoinvent.

The Phase 2 trial (Clinicaltrial.gov: NCT06504147) is a randomized controlled trial assessing the efficacy and safety of Radspherin® in patients with peritoneal metastases from ovarian cancer. The primary objective is to compare progression-free survival (PFS) between patients who receive Radspherin® after complete surgical resection following pre-operative chemotherapy, and patients receiving pre-operative chemotherapy and surgery alone.

The study will recruit patients at a total of 11 sites across Norway (1), Spain (5), Belgium (1), the United Kingdom (2), the United States (1), and Italy (1). Positive Phase 1/2a data from the safety interim analysis demonstrated that Radspherin® was well tolerated with no dose-limiting toxicity observed at the recommended dose of 7MBq.

About Oncoinvent

Oncoinvent is a clinical-stage biotechnology company developing novel radiopharmaceutical therapies against cancer. The lead product candidate, Radspherin®, uses the alpha-emitting radionuclide radium-224, directly targeting micro-metastases post-surgery, harnessing the benefits of modern radiopharmaceuticals without the complexities of biological targeting. Oncoinvent is investigating the safety and efficacy of Radspherin® in a clinical development program in two indications. One Phase 1 trial and one Phase 1/2a trial have been completed and one randomized Phase 2 trial is currently ongoing in the US and Europe. Early clinical efficacy data are highly encouraging, and no serious toxicity or safety concerns have been reported to date. The Oncoinvent team consists of approximately 40 employees and operates a state-of-the-art manufacturing facility to produce drug products for clinical trials in Oslo, Norway. Oncoinvent is listed on the Oslo Stock Exchange (ONCIN).

About Radspherin

Radspherin® is an investigational radiopharmaceutical designed for the local treatment of cancer that has spread to body cavities. It consists of billions of calcium carbonate microparticles containing the radioactive material radium-224. The mode of action is the decay of radium-224 emitting alpha-particles, a highly potent form of ionizing radiation. Radspherin® is investigated in clinical studies to treat peritoneal carcinomatoses from ovarian and colorectal cancer and it is administered intraperitoneally following surgical resection with removal of all macroscopic disease.

Forward-Looking Statements

All statements other than statements of historical facts contained in this press release are forward-looking statements and are not a representation that Oncoinvent’s plans, estimates, or expectations will be achieved. These forward-looking statements represent Oncoinvent’s expectations as of the date of this press release, and Oncoinvent disclaims any obligation to update the forward-looking statements. These forward-looking statements are subject to known and unknown risks and uncertainties that may cause actual results to differ materially, including with respect to whether the results of clinical or other studies will support the use of our product offerings, the impact of results of such studies, our expectations of the reliability, accuracy and performance of our tests, or of the benefits of our tests and product offerings to patients, providers and payers.