Oncoinvent ASA

Regulatory Filings • Dec 8, 2025

Oncoinvent Announces Publication of Phase 1 Study Results for Radspherin® in Ovarian Cancer in Gynecologic Oncology

Oncoinvent Announces Publication of Phase 1 Study Results for Radspherin® in Ovarian Cancer in Gynecologic Oncology

Oslo, Norway, 8 December 2025 - Oncoinvent, a clinical stage,

radiopharmaceutical company developing innovative treatments for solid cancers,

today announced the publication of 12-month data from its Phase 1 study of

patients with platinum-sensitive recurrent ovarian cancer and peritoneal

carcinomatosis. The results from the first patients have been published in the

respected peer-reviewed journal Gynecologic Oncology, under the title: "First

experience with intraperitoneal 224Ra-labeled microparticles after cytoreductive

surgery in patients with peritoneal recurrence of platinum-sensitive epithelial

ovarian

cancer (https://www.sciencedirect.com/science/article/pii/S0090825825011023)."

"We are proud to announce that our article has been published in Gynecologic

Oncology. This recognition underscores the importance of our research and

validates our ongoing efforts. As our phase 2 study progresses in patients with

peritoneal metastasis from ovarian cancer, we remain fully committed to

advancing new treatment options to address this urgent medical need," said Kari

Myren, Chief Medical Officer at Oncoinvent.

The primary objectives of the phase 1 study were to evaluate the safety and

tolerability of the alpha emitting therapy using [224]Ra-labeled microparticles

(Radspherin®)[ ]and to determine the recommended dose for subsequent clinical

development. Initial experiences indicate that all dose levels were well

tolerated, no dose limiting toxicity was observed during dose escalation and the

highest dose of 7 MBq was selected as the recommended dose for the expansion

phase.  Alongside the now published  12-month data, Oncoinvent has also released

topline 24-month follow-up data for the phase 1

study (https://www.oncoinvent.com/press-release/oncoinvent-reports-positive

-final-data-from-phase-1-trial-of-radspherin-to-treat-ovarian-cancer/) in

ovarian cancer patients.

A randomized controlled phase 2 study is ongoing to evaluate the efficacy and

safety of Radspherin® in patients with peritoneal metastasis from ovarian

cancer. The primary aim is to compare progression-free survival (PFS) between

two groups: those who receive Radspherin® following complete surgical resection

after pre-operative chemotherapy, and those treated with pre-operative

chemotherapy and surgery alone. Further details can be found at

clinicaltrials.gov (https://clinicaltrials.gov/study/NCT06504147).

For further information, please contact:

Øystein Soug, Chief Executive Officer

Email: soug@oncoinvent.com

Renate Birkeli, Director Investor Relations

Email: birkeli@onconinvent.com

Optimum Strategic Communications

Mary Clark, Zoe Bolt, Elena Bates

+44 (0) 203 882 9621

oncoinvent@optimumcomms.com

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, UK 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 Oslo Stock Exchange.

About Radspherin

Radspherin® is an investigational radiopharmaceutical designed for the local

treatment of cancer that has spread to body cavities. It consists 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.