Clinical-stage radiopharmaceutical company Oncoinvent ASA (Euronext Growth Oslo:ONCIN) on Wednesday announced final results from its Phase 1/2a trial evaluating Radspherin in patients with peritoneal metastases originating from colorectal cancer.

The study enrolled 47 patients, with 36 receiving a 7 MBq dose of Radspherin. At 18 months, only 27.8% of treated patients experienced peritoneal recurrence, compared to approximately 50% in published standard-of-care data. Among all recurrences, just 22.7% had the peritoneum as the first site of relapse.

The trial confirmed a favourable safety profile and demonstrated sustained peritoneal disease control, highlighting Radspherin's potential to eliminate microscopic cancer deposits left after surgery.

Radspherin, which delivers radium-224 directly into the peritoneal cavity, targets residual micro-metastases to delay or prevent disease progression. Peritoneal metastases in colorectal cancer are linked with poor prognosis, high symptom burden, and limited therapeutic options beyond surgery.

The therapy is also under evaluation in an ongoing Phase 2 trial for peritoneal carcinomatosis from ovarian cancer, which is progressing according to plan across European and US sites.