· First patient enrolled in newly activated site

Oslo, Norway, 29 January 2026: Oncoinvent, a clinical stage, radiopharmaceutical
company developing innovative treatments for solid cancers, today announces that
the first patient has been enrolled at one of the newly activated sites in its
Phase 2 study of Radspherin[®] in patients with peritoneal carcinomatosis from
ovarian cancer.

The randomized part of the study has been actively recruiting patients at six
sites since March 2025. Four additional sites have now been opened, and the
first patient has been enrolled at one of these newly activated sites.

"The process of opening new clinical sites involves extensive regulatory
reviews, contracting, and site-readiness work. We are therefore pleased to see
both the successful activation of additional sites and the enrollment of the
first patient at a newly onboarded site," said Kari Myren, Chief Medical Officer
at Oncoinvent.

The Phase 2 trial (Clinicaltrial.gov: NCT06504147) is a randomized controlled
trial assessing the efficacy and safety of Radspherin[®] in patients with
peritoneal metastases from ovarian cancer. The primary objective is to compare
progression-free survival (PFS) between patients who receive Radspherin[®] after
complete surgical resection following pre-operative chemotherapy, and patients
receiving pre-operative chemotherapy and surgery alone.

The study will recruit patients at a total of 11 sites across Norway (1), Spain
(5), Belgium (1), the United Kingdom (2), the United States (1), and Italy (1).
Positive Phase 1/2a data from the safety interim analysis demonstrated that
Radspherin[®] was well tolerated with no dose-limiting toxicity observed at the
recommended dose of 7MBq.

For further information, please contact:
Ramzi Amri, Chief Financial Officer
Email: amri@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 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 approximately 40 employees and operates a
state-of-the-art manufacturing facility to produce drug products for clinical
trials in Oslo, Norway. Oncoinvent is listed on the Oslo Stock Exchange (ONCIN).

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 following surgical resection with
removal of all macroscopic disease.

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.