Oncoinvent Presents Preliminary 18-Month Safety and Efficacy Data from Ongoing RAD-18-002 Phase 1/2A Trial of Radspherin® in Colorectal Cancer Patients at the 13th PSOGI International Congress on Peritoneal Surface Malignancies

At 18 months, no patients at the recommended dose of 7 MBq experienced peritoneal recurrences

Robust safety profile demonstrated, no serious adverse events related to Radspherin^® reported

Presentation on October 4, 2023, at 11:55 a.m. CET (5:55 a.m. EDT)

Oncoinvent AS, a clinical stage company advancing alpha emitter therapy across a variety of solid cancers, today announced the presentation of preliminary 18-month safety and efficacy data from its ongoing Phase 1/2A clinical trial evaluating the safety, tolerability, and signal of efficacy of Radspherin® in patients with peritoneal carcinomatosis from colorectal cancer at the 13th International Congress on Peritoneal Surface Malignancies of the Peritoneal Surface Oncology Group International (PSOGI), to be held at the Palazzo del Cinema in Venice, Italy from October 4 - 6, 2023. The presentation, titled “18-month safety and efficacy after intraperitoneal treatment with ²²⁴Radium-labelled microparticles (Radspherin) after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) for colorectal peritoneal metastasis (PM)” will be presented on October 4, 2023 from 11:55 a.m. to 12:05 p.m. CET (5:55 a.m. EDT).

“We are thrilled to continue to demonstrate the robust safety and efficacy profile of Radspherin® with the presentation of 18-month data at PSOGI. At 18 months, none of the patients administered Radspherin® at the recommended dose experienced peritoneal recurrences. Along with a demonstrated robust safety profile, we believe Radspherin® has potential as a novel treatment,” said Anders Månsson, Chief Executive Officer of Oncoinvent. “These data represent a significant clinical milestone for Radspherin®, giving us confidence in its potential to prevent peritoneal recurrence. We look forward to the continued clinical development of this promising therapy.”

Details of the oral presentations are as follows:

Oral Presentation Session: Session II Oral Abstract – Colorectal Cancer

Presentation Title: 18-month safety and efficacy after intraperitoneal treatment with ²²⁴Radium-labelled microparticles (Radspherin) after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) for colorectal peritoneal metastasis (PM)

Presenting Author: Stein Gunnar Larsen, MD, PhD, Oslo University Hospital, the Norwegian Radium Hospital.

Oral Presentation Date and Time: October 4^th, 2023, from 11:55 a.m. to 12:05 p.m. CET (5:55 a.m. EDT).

This Phase 1/2A study is designed to evaluate the safety, tolerability, and signal of efficacy of Radspherin® injected intraperitoneally two days after the completion of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). A dose of 7 MBq was recommended following the completion of dose escalation 1-2-4-7 MBq. A total of 23 patients with peritoneal metastasis from colorectal cancer were enrolled, with 12 receiving the recommended dose of 7MBq. Preliminary safety and survival data at 18-months is presented.

Key results:

• At 18 months, none of the 12 patients who received the recommended dose of 7 MBq experienced peritoneal recurrences
• Only 2.6% of all adverse events reported were considered to be related to Radspherin®, all of which were grade 1-2

Additionally, a poster demonstrating Radspherin® as a novel radiopharmaceutical for treatment for peritoneal metastasis will be presented on October 4th, 2023

Poster Presentation Session: Treatment and Prevention of Peritoneal Metastases from Colorectal Cancer

Poster Title: Novel radiopharmaceutical for intraperitoneal treatment of peritoneal metastasis from colorectal and ovarian cancer after complete surgical resection

Presenting Author: Kari Myren, Oncoinvent AS

Poster Presentation Date and Time: October 4^th, 2023, from 1:00 p.m. to 1:30 p.m. CET (7:00 a.m. to 7:30 a.m. EDT)

About Oncoinvent

Oncoinvent AS is a clinical stage company developing innovative radiopharmaceutical technology that delivers precise, alpha-emitting particles across solid cancers. By leveraging internal manufacturing and supply chain capabilities to enable a clinical supply of radioisotopes, the company is advancing a pipeline of novel products that use alpha particles, a higher Linear Energy Transfer (LET) form of radiation, that can potentially eradicate cancer cells. Oncoinvent’s lead candidate, Radspherin®, is designed for treatment of metastatic cancers in body cavities, and its versatility allows it to be deployed for the treatment of a variety of cancer indications. Radspherin® is in two ongoing clinical studies to treat peritoneal carcinomatosis from both ovarian cancer and colorectal cancer.

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