Oncoinvent ASA: Oncoinvent announces publication of normal tissue dosimetry results in Journal of Nuclear Medicine

Oslo, Norway, 11 August 2026 - Oncoinvent, a biotech company developing a receptor-independent alpha radiopharmaceutical to eradicate cancer cells in the abdominal cavity after surgery with a single, targeted dose, today announces the publication of clinical dosimetry data for Radspherin^® in the Journal of Nuclear Medicine, one of the leading peer-reviewed journals in the field.

The publication, titled "Normal Tissue Dosimetry of Intraperitoneal Radium-224-Microparticle Therapy: Data from First-in-Human Studies in Patients with Peritoneal Metastases", reports results from nine patients enrolled in the dosimetry cohorts of the Phase 1 Radspherin^® studies in ovarian and colorectal cancer. Positive final data from these studies, previously reported by Oncoinvent, demonstrated a favorable safety profile and encouraging efficacy signals.

"In early-phase clinical studies, dosimetry is essential to understand how radiation exposure relates to potential toxicity and identify potential dose-limiting tissues," said Caroline Stokke, senior author of the publication, Head of Nuclear Medicine Physics at Oslo University Hospital and Chair of the European Association of Nuclear Medicine Dosimetry Committee. "This work also reflects the methodological complexity of dosimetry for alpha therapies, where imaging cannot always be directly applied. To address these challenges, we were able to use a combination approach, also including blood sampling and biokinetic modeling, to estimate normal tissue radiation exposure and provide a basis for evaluating safety."

The dosimetry study, conducted at The Norwegian Radium Hospital, part of Oslo University Hospital, evaluated how radiation from Radspherin^® is distributed to normal tissues following treatment. Results showed that absorbed radiation doses to normal organs were below levels commonly associated with risks for complications, including for organs typically regarded as activity-limiting such as the kidneys and red bone marrow.

"We are pleased to report the results from the outstanding work performed together with Oslo University Hospital published in the prestigious Journal of Nuclear Medicine," said Kari Myren, Chief Medical Officer at Oncoinvent. "Unintended radiation exposure to normal organs, especially for the kidneys and red bone marrow, frequently represents a limitation for obtaining therapeutic doses of radiopharmaceuticals. Our results indicate very low radiation exposure to healthy organs after treatment, which is consistent with the favorable safety profile observed in our clinical trials and supports the further development of Radspherin^® to provide hope for patients for whom very limited treatment options exist."

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