Oncoinvent Presents Final Safety and Efficacy Results from the Phase 1/2a Trial of Radspherin® to Treat Colorectal Cancer at the 15th PSOGI International Congress on Peritoneal Surface Malignancies

29 Oct 2025 15:16 CET

Oncoinvent ASA, a clinical-stage radiopharmaceutical company developing
innovative treatments for solid cancers, today announced the presentation of the
previously reported final 18-months safety and efficacy results from  its Phase
1/2a clinical trial (RAD-18-002) evaluating Radspherin® in patients with
peritoneal metastases from colorectal cancer at the 15th PSOGI International
Congress on Peritoneal Surface Malignancies, to be held at the Fira Barcelona
October 29-31, 2025. 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 1/2a trial, 36 out of 47 patients received the highest and
recommended intraperitoneal dose of 7 MBq Radspherin® after dose escalation (1,
2, 4 and 7 MBq). The final 18-month data reported that only 10 of these 36
patients (27.8 %) had peritoneal recurrence. Remarkably, only 2 out of the 36
patients experienced peritoneal metastases as the only site of disease
recurrence. Further, at 18 months 61.1% (22 of 36) patients had experienced new
metastases overall, giving a median disease-free survival of 13.5 months.

"We are delighted to have the opportunity to present these encouraging data at
such a highly specialized conference dedicated to peritoneal surface
malignancies," said Øystein Soug, CEO of Oncoinvent. "The theme of this year's
PSOGI conference - 'From small beginnings to global force' - perfectly reflects
our ambitions for the development of Radspherin®."

The results strengthen the potential for Radspherin® as a novel treatment option
for patients with peritoneal metastases from colorectal cancer, demonstrating
both clinical promise, as well as being well tolerated and safe to use,
concludes the presenting author Dr. Stein Gunnar Larsen, Principal Investigator
from the Norwegian Radium Hospital, Oslo University Hospital in Norway in the
presented abstract.

About RAD-18-002

RAD-18-002 was an open label Phase 1/2a trial conducted in patients with
peritoneal metastases from colorectal cancer. The trial was designed to evaluate
dosing, safety and tolerability, and signal of efficacy of intraperitoneally
administered Radspherin® following complete surgical resection and hyperthermic
intraperitoneal chemotherapy (HIPEC). A total of 47 patients were enrolled
across sites in Norway and Sweden.

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 approx. 40 employees and runs a state-of-the-art
manufacturing facility to produce drug products for clinical trials in Nydalen,
Oslo. Oncoinvent is listed on the Euronext Growth Oslo.

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 after surgical resection with removal
of all macroscopic tumors.

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.

For further information, please contact:

Oystein Soug, Chief Executive Officer
Email: soug@oncoinvent.com

Tore Kvam, Chief Financial Officer
Email: kvam@oncoinvent.com

More information:
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