Oncoinvent ASA (Euronext Growth Oslo:ONCIN), a Norway-based clinical-stage radiopharmaceutical company developing innovative treatments for solid cancers, on Wednesday reported positive final 24-month follow-up results from its Phase 1 clinical trial (RAD-18-001) evaluating Radspherin in patients with platinum-sensitive recurrent ovarian cancer and peritoneal carcinomatosis.

Radspherin, direct intraperitoneal targeting with the alpha-emitter radium-224, aims to eliminate post-surgery micro-metastases and thereby prevent or delay peritoneal recurrence.

In this Phase 1 trial, 10 out of 21 patients received the highest and recommended intraperitoneal dose of 7 MBq Radspherin after dose escalation (1, 2, 4 and 7 MBq). The final 24-month data still indicates that only 1 of these 10 patients had peritoneal recurrence, and peritoneal recurrence rate remains at 10%.

RAD-18-001 was an open label Phase 1 trial conducted in patients with peritoneal metastases in platinum-sensitive recurrent ovarian cancer. The trial was designed to evaluate dosing, safety and tolerability, and signal of efficacy of intraperitoneally administered Radspherin following complete surgical resection. A total of 21 patients were enrolled across sites in Norway, Belgium and Spain.

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 ionising radiation. Radspherin is being investigated in clinical studies to treat peritoneal carcinomatoses from ovarian and colorectal cancer and it is administered intraperitoneally after surgical resection with removal of all macroscopic tumours.