OSE Immunotherapeutics Receives Second Positive IDMC Recommendation for Phase 3 ARTEMIA Trial Evaluating Tedopi® in Non-Small Cell Lung Cancer

NANTES, France, February 26, 2026 – 6pm CET - OSE Immunotherapeutics SA (ISIN: FR0012127173; Mnemo: OSE), today announced that the Independent Data Monitoring Committee (IDMC) has issued a second positive recommendation for the ongoing pivotal Phase 3 ARTEMIA trial evaluating Tedopi® in advanced non-small cell lung cancer (NSCLC). The IDMC advised that the study should continue as planned, with no protocol changes.

In line with the predefined study oversight plan, the IDMC, composed of independent clinical and statistical experts, conducted a comprehensive assessment of patient safety, trial conduct and key efficacy indicators. Based on this review, the IDMC recommended that the study continue without modifications, confirming the robustness of the trial’s conduct to date.

Dr. Silvia Comis, Chief Clinical and Medical Research Officer at OSE Immunotherapeutics, commented: “We welcome this new positive assessment from the IDMC. A total of 163 patients had been randomized at the time of the meeting, with 152 included in the analysis reviewed by the IDMC. These figures are fully consistent with our recruitment objectives.”

Initiated in 2024, ARTEMIA compares Tedopi® monotherapy with standard docetaxel in HLA-A2–positive patients with metastatic NSCLC who have developed secondary resistance to immune checkpoint inhibitors. The trial is enrolling across sites in Europe, the UK, the US and Canada and is designed to generate confirmatory data to support potential regulatory filings.

The next IDMC review is scheduled for October 2026. Study enrollment is expected to conclude by year-end 2026. Tedopi® NSCLC Pivotal Phase 3 interim futility analysis is expected in Q3 2026, with overall survival primary endpoint results anticipated in Q1 2028.

About OSE Immunotherapeutics

OSE Immunotherapeutics is a biotech company dedicated to developing first-in-class assets in immuno-oncology (IO) and immuno-inflammation (I&I) that address the unmet patient needs of today and tomorrow. We partner with leading academic institutions and biopharmaceutical companies in our efforts to develop and bring to the market transformative medicines for people with serious diseases. OSE Immunotherapeutics is based between Nantes and Paris and is listed on Euronext. Additional information about OSE Immunotherapeutics assets is available on the Company’s website: www.ose-immuno.com. Follow us on LinkedIn.